Importance of preovulatory estradiol on uterine receptivity and luteal function

Animals that exhibited estrus had greater pregnancy success compared to animals that did not exhibit estrus before fixed-time AI (FTAI). Estradiol is synthesized in bovine ovarian follicles under gonadotropin regulation and can directly and indirectly regulate the uterine receptivity and luteal function. Estradiol concentrations at FTAI impacted oviductal gene expression and has been reported to play an important role in establishing the timing of uterine receptivity. These changes have been reported to impact uterine pH and sperm transport to the site of fertilization. After fertilization, preovulatory estradiol has been reported to improve embryo survival likely by mediating changes in uterine blood flow, endometrial thickness and changes in histotroph. Cows with greater estradiol concentrations at the time of GnRH-induced ovulation also had a larger dominant follicle size and greater circulating progesterone concentrations on day 7. Therefore, it is impossible to accurately determine the individual benefit of greater estradiol concentrations prior to ovulation and greater progesterone concentrations following ovulation to pregnancy establishment, as these two measurements are confounded. Research has indicated an importance in the occurrence and timing of increasing preovulatory concentrations of estradiol, but increasing estradiol concentrations by supplementation may not be sufficient to increase fertility. Increased production of estradiol by the preovulatory follicle may be required to enhance fertility through the regulation of sperm transport, fertilization, oviductal secretions, the uterine environment, and embryo survival.(AU)

Efeitos de hormônios esteroides de contraceptivos orais combinados sobre os parâmetros comportamentais de Betta splendens (Regan, 1909) / Effects of steroid hormones from combined oral contraceptives on the behavioral and physiological parameters of Betta splendens (Regan, 1909)

Os hormônios esteroides presentes em várias gerações de contraceptivos orais combinados (COC) podem se apresentar como disruptores endócrinos, produzindo alterações no comportamento e na fisiologia de peixes. Diante disso, o objetivo deste trabalho foi avaliar os efeitos de hormônios esteroides presentes em COC sobre os parâmetros comportamentais de Betta splendens, um peixe ornamental usado na aquariofilia e bastante agressivo. Machos adultos foram observados pelo método ad libitum para confecção do etograma e divididos em cinco grupos, controle e expostos aos hormônios: 17β-estradiol (E2); levonorgestrel e etinilestradiol (LEA - segunda geração de COC); gestodeno e etinilestradiol (GEA - terceira geração de COC); e drospirenona e etinilestradiol (DEA - quarta geração de COC). Os peixes foram expostos por 30 dias à concentração final de 10ng/L. Foram avaliados os comportamentos pelos métodos de varredura instantânea e animal-focal, bem como o consumo de ração. No método varredura, o comportamento descansar apresentou o maior valor (54,4±10,1%) no grupo E2 (P<0,05). Os comportamentos agressivos de carga (16,1±3,6%) e recuar e carga (16,4±5,1%) apresentaram os maiores valores no grupo controle em relação aos demais grupos (P<0,05). Os animais do grupo E2 apresentaram maior frequência de comportamentos inativos (76,1%) comparados aos de outros grupos. O comportamento atípico natação errática não foi observado no grupo controle, mas foi observado nos grupos experimentais. Os grupos E2, LEA, GEA e DEA apresentaram redução nos comportamentos agressivos (10%) quando comparados ao grupo controle pelo método animal-focal. Não foram observadas diferenças na exibição desses comportamentos ao se compararem os animais expostos às diferentes gerações de contraceptivos e no consumo de ração. Pode-se concluir que 17β-estradiol causou mais efeitos aos peixes e que diferentes gerações de COC apresentaram efeitos tóxicos semelhantes em relação aos comportamentos observados.(AU)

The steroid hormones present in many generations of combined oral contraceptives (COC) can act as endocrine disruptors inducing changes in the behavior and physiology of fish. In this context, the aim of this work was to evaluate the effects of steroid hormones present in COC on behavioral parameters of Betta splendes, an aggressive ornamental fish used in the aquariophily. Adult males were observed with the ad libitum method to develop an ethogram and were divided into five groups, Control and exposed to hormones: 17β-estradiol (E2), levonorgestrel and ethinylestradiol (LEA - 2nd COC generation), gestodene and ethinylestradiol (GEA - 3rd COC generation) and drospirenone and ethinylestradiol (DEA - 4th COC Generation). Fish were exposed for 30 days to a final concentration of 10ng/L. The behavior was evaluated by scan sampling and animal-focal methods, and feed intake. In the scan sampling method, the Resting behavior showed the highest value (54.4±10.1%) in E2 group (P<0.05). The aggressive behavior Rush (16.1±3.6%) and Back and Rush (16.4±5.1%) showed the highest values in the control group, compared to the other groups (P<0.05). Animals in the E2 group showed higher frequency of inactive behaviors (76.1%) compared to other groups. Furthermore, the atypical behavior Erratic swimming was not observed in the control group, but it was observed in the experimental groups. The E2, LEA, GEA and DEA groups showed reduction in aggressive behavior (10%) compared to the control group by the animal-focal method. Moreover, no difference was observed in the exhibition of these behaviors and feed intake comparing animals exposed to the different generations of contraceptives. It can be concluded that 17β-estradiol has caused more effects on fish and different generations of COC showed similar toxic effects in the observed behaviors.(AU)

Efeito da somatotropina recombinante bovina (rbST) no perfil plasmático da progesterona, estradiol, hormônio do crescimento e IGF-1 de fêmeas bovinas / Effect of recombinant bovine somatotropin (rbST) on the plasma levels of progesterone, estradiol, growth hormone and IGF-1 of females bovines

This study aimed to evaluate the effect of recombinant bovine somatotropin on the plasma levels ofprogesterone, estradiol, growth hormone and IGF-1. 8 cows Girolando were divided into three groups: control,250 mg rbST and 500 mg rbST. Blood samples were collected 60 days prior to aspiration, in 12-day intervals,with the samples taken on the same days of rbST applications. For hormone measurements, ELISA commercialkits were used. The hormone concentrations were subjected to the normal pattern Cramer-von Mises and foraverage of comparison, the test Student-Newman-Keuls (SNK) was used, with 5% probability. It was notpossible to measure the plasma concentration of GH hormone. The rbST administration had no effect on plasmaconcentrations of progesterone, estradiol and IGF-1 among the groups treated with 250 mg and 500 mg and theuntreated group, there was also no significant variance between the days of application and OPUs.(AU)

Efeito da somatotropina recombinante bovina (rbST) no perfil plasmático da progesterona, estradiol, hormônio do crescimento e IGF-1 de fêmeas bovinas / Effect of recombinant bovine somatotropin (rbST) on the plasma levels of progesterone, estradiol, growth hormone and IGF-1 of females bovines

This study aimed to evaluate the effect of recombinant bovine somatotropin on the plasma levels ofprogesterone, estradiol, growth hormone and IGF-1. 8 cows Girolando were divided into three groups: control,250 mg rbST and 500 mg rbST. Blood samples were collected 60 days prior to aspiration, in 12-day intervals,with the samples taken on the same days of rbST applications. For hormone measurements, ELISA commercialkits were used. The hormone concentrations were subjected to the normal pattern Cramer-von Mises and foraverage of comparison, the test Student-Newman-Keuls (SNK) was used, with 5% probability. It was notpossible to measure the plasma concentration of GH hormone. The rbST administration had no effect on plasmaconcentrations of progesterone, estradiol and IGF-1 among the groups treated with 250 mg and 500 mg and theuntreated group, there was also no significant variance between the days of application and OPUs.

Effect of estradiol-17 on the sex ratio, growth and survival of juvenile common snook (Centropomus undecimalis) / Efeito do estradiol-17β na feminização, crescimento e sobrevivência de juvenis de robalo-flecha (Centropomus undecimalis)

Sex control in fish is a promising technique for aquaculture, since it gives advantages associated with one sex. The aim of this study was to investigate the feminization of common snook (Centropomus undecimalis) by oral administration of two doses of estradiol-17 (50 and 100 mg E2 kg-1 feed) and control treatment for 45 days and to evaluate their effects on the sex ratio, growth and survival of common snook juveniles. After this period, fish were fed only with commercial feed without hormone supplementation. During the period of E2 administration, the control fish grew more than those in the other treatments. At the end of the experiment in the treatment with 50 mg E2 kg-1, 26.32% of the fish were male, 68.42% were female, and 5.26% were intersex. In the treatment with 100 mg E2 kg-1, 10% of the fish were male, and 90% were female. There was no difference in growth among the treatments after 11 months. This study showed that it is possible to obtain 90% common snook females using feeds with 100 mg E2 kg-1 for 45 days without impairing the fish growth or survival.

O controle do sexo dos peixes é uma técnica promissora na aquicultura, pois permite obter vantagens associadas a um dos sexos. Sendo assim, o objetivo deste trabalho foi avaliar o efeito do hormônio 17β-estradiol (E2) na feminização, crescimento e sobrevivência de juvenis de robalo-flecha (Centropomus undecimalis). Durante 45 dias, os juvenis foram submetidos a três dietas (controle, 50, 100 mg E2 kg-1 de ração) com três repetições cada. Após este período, os peixes passaram a ser alimentados somente com ração comercial sem adição de hormônio. Durante o período de administração do E2, os peixes do controle cresceram mais que os dos outros tratamentos. No final do experimento, no tratamento com 50 mg E2 kg-1, 26% dos peixes eram machos, 68.42% eram fêmeas e 5.26% eram intersexo. No tratamento com 100 mg E2 kg-1, 10% dos peixes eram machos e 90% eram fêmeas. Após 11 meses não houve diferença de crescimento entre os tratamentos. Este trabalho mostrou que é possível obter 90% de fêmeas de robaloflecha utilizando rações com 100 mg E2 kg-1 durante 45 dias sem danos ao crescimento ou à sobrevivência.

Effect of estradiol-17 on the sex ratio, growth and survival of juvenile common snook (Centropomus undecimalis) / Efeito do estradiol-17β na feminização, crescimento e sobrevivência de juvenis de robalo-flecha (Centropomus undecimalis)

Sex control in fish is a promising technique for aquaculture, since it gives advantages associated with one sex. The aim of this study was to investigate the feminization of common snook (Centropomus undecimalis) by oral administration of two doses of estradiol-17 (50 and 100 mg E2 kg-1 feed) and control treatment for 45 days and to evaluate their effects on the sex ratio, growth and survival of common snook juveniles. After this period, fish were fed only with commercial feed without hormone supplementation. During the period of E2 administration, the control fish grew more than those in the other treatments. At the end of the experiment in the treatment with 50 mg E2 kg-1, 26.32% of the fish were male, 68.42% were female, and 5.26% were intersex. In the treatment with 100 mg E2 kg-1, 10% of the fish were male, and 90% were female. There was no difference in growth among the treatments after 11 months. This study showed that it is possible to obtain 90% common snook females using feeds with 100 mg E2 kg-1 for 45 days without impairing the fish growth or survival.(AU)

O controle do sexo dos peixes é uma técnica promissora na aquicultura, pois permite obter vantagens associadas a um dos sexos. Sendo assim, o objetivo deste trabalho foi avaliar o efeito do hormônio 17β-estradiol (E2) na feminização, crescimento e sobrevivência de juvenis de robalo-flecha (Centropomus undecimalis). Durante 45 dias, os juvenis foram submetidos a três dietas (controle, 50, 100 mg E2 kg-1 de ração) com três repetições cada. Após este período, os peixes passaram a ser alimentados somente com ração comercial sem adição de hormônio. Durante o período de administração do E2, os peixes do controle cresceram mais que os dos outros tratamentos. No final do experimento, no tratamento com 50 mg E2 kg-1, 26% dos peixes eram machos, 68.42% eram fêmeas e 5.26% eram intersexo. No tratamento com 100 mg E2 kg-1, 10% dos peixes eram machos e 90% eram fêmeas. Após 11 meses não houve diferença de crescimento entre os tratamentos. Este trabalho mostrou que é possível obter 90% de fêmeas de robaloflecha utilizando rações com 100 mg E2 kg-1 durante 45 dias sem danos ao crescimento ou à sobrevivência.(AU)

Role of angiotensin II on follicle development and ovulation

We will address, in this review, the role of angiotensin II (AngII) on follicular development and ovulation. Over the last few years, our research group has focused on studying the contribution of renin-angiotensin system in antral follicle development and ovulation and a new concept of local regulation has been established using cattle as a model. We previously demonstrated that AT1 and AT2 receptors are expressed in both granulosa and theca cells. The abundance of AT2 mRNA in granulosa cells was higher in healthy compared with atretic follicles, whereas both receptors in theca cells and AT1 in granulosa cells did not change. Granulosa cells cultured with hormones that stimulate estradiol secretion increased AT2 mRNA and protein levels, whereas fibroblast growth factors (FGF-7 and 10) inhibited estradiol secretion and AT2 protein levels. We also found that the concentration of AngII increases in dominant follicle at expected time for follicular deviation. Transvaginal ultrasound has been used for intrafollicular injection to understand the regulation of follicular wave and ovulation. With this in vivo model, we have demonstrated that AngII-receptor blocker inhibits follicular growth and decreases estradiol concentration in follicular fluid and downregulates mRNA expression of genes involved in follicular development. Moreover, intrafollicular injection of AngII or AT2-specific agonist prevented the expected atresia of the second largest follicle, which continued to grow at a rate similar to the dominant follicle for 24 h. These findings have provided evidence that AngII plays an important role in follicle development. In regarding to ovulation, we demonstrated that AngII antagonists block ovulation in cattle when intrafollicularly injected at 0 and 6 h after applying GnRH agonist. Ovulation was also inhibited by AT2- but not by AT1-AngII receptor antagonist. Furthermore, AngII stimulates an enhancement in mRNA abundance of genes involved in ovulation. In addition, AngII stimulates genes involved in extracellular remodeling and follicular wall rupture. In conclusion, our data from in vitro and in vivo studies have demonstrated that AngII plays a pivotal role in the antral follicle development and early mechanism of ovulation via the AT2 receptor subtype in cattle.

Role of angiotensin II on follicle development and ovulation

We will address, in this review, the role of angiotensin II (AngII) on follicular development and ovulation. Over the last few years, our research group has focused on studying the contribution of renin-angiotensin system in antral follicle development and ovulation and a new concept of local regulation has been established using cattle as a model. We previously demonstrated that AT1 and AT2 receptors are expressed in both granulosa and theca cells. The abundance of AT2 mRNA in granulosa cells was higher in healthy compared with atretic follicles, whereas both receptors in theca cells and AT1 in granulosa cells did not change. Granulosa cells cultured with hormones that stimulate estradiol secretion increased AT2 mRNA and protein levels, whereas fibroblast growth factors (FGF-7 and 10) inhibited estradiol secretion and AT2 protein levels. We also found that the concentration of AngII increases in dominant follicle at expected time for follicular deviation. Transvaginal ultrasound has been used for intrafollicular injection to understand the regulation of follicular wave and ovulation. With this in vivo model, we have demonstrated that AngII-receptor blocker inhibits follicular growth and decreases estradiol concentration in follicular fluid and downregulates mRNA expression of genes involved in follicular development. Moreover, intrafollicular injection of AngII or AT2-specific agonist prevented the expected atresia of the second largest follicle, which continued to grow at a rate similar to the dominant follicle for 24 h. These findings have provided evidence that AngII plays an important role in follicle development. In regarding to ovulation, we demonstrated that AngII antagonists block ovulation in cattle when intrafollicularly injected at 0 and 6 h after applying GnRH agonist. Ovulation was also inhibited by AT2- but not by AT1-AngII receptor antagonist. Furthermore, AngII stimulates an enhancement in mRNA abundance of genes involved in ovulation. In addition, AngII stimulates genes involved in extracellular remodeling and follicular wall rupture. In conclusion, our data from in vitro and in vivo studies have demonstrated that AngII plays a pivotal role in the antral follicle development and early mechanism of ovulation via the AT2 receptor subtype in cattle.(AU)

The influence of estrogen on liver regeneration: an experimental study in rats / A influência do estrogênio na regeneração hepática: estudo experimental em ratos

To recognize the regenerative capacity influenced by the administrating of estradiol. METHODS: 42 female Wistar rats were used, divided into two groups, the control and the experiment group. A resection of approximately 70 percent of the liver was made in the liver of these animals. The control group received an intramuscular injection of one ml of peanut oil. The experiment group were given estradiol hexahydrobenzoate (50µg) diluted in one ml of peanut oil. Calibrations were done after 36 hours and 7 days, using three methods: the formula of Kwon et al.21, to recognize gain in volume, counting of the mitosis figures in five fields and the percentage of positive PCNA nuclei. RESULTS: Gain in volume (mass) was similar in both groups after 36 hours (p=0.1873) and higher in the experiment groups after seven days (p=0.0447). Microscopy showed a similar number of mitosis figures after 36 hours (p=0.3528) and a tendency to be higher in the experiment group after 7 days (p=0.0883). The average of positive PCNA nuclei was higher in the experiment group both after 36 hours (p=0.0009) and 7 days (p=0.0000). CONCLUSION: The estradiol hexahydrobenzoate improved liver regeneration in rats submitted to a 70 percent hepatectomy.(AU)

Reconhecer a capacidade regenerativa influenciada pela administração de estradiol. MÉTODOS: Utilizaram-se 42 ratos Wistar, fêmeas, divididos em dois grupos controle e experimento. Realizou-se a ressecção de, aproximadamente, 70 por cento do fígado destes animais. Ratos do grupo controle receberam injeção intramuscular de um mililitro de óleo de amendoim, enquanto que os do grupo experimento receberam hexaidrobenzoato de estradiol (50µg) diluídos em um mililitro de óleo de amendoim. Fizeram-se as aferições com 36 horas e 7 dias, com 3 métodos: Fórmula de Kwon et al.21 para reconhecer ganho de volume, contagem das figuras de mitose existentes em 5 campos e percentual dos núcleos PCNA positivos em 5 campos. RESULTADOS: O ganho de volume (massa) foi semelhante nos dois grupos com 36 horas (p=0,1873) e maior no grupo experimento com 7 dias (p=0,0447). À microscopia observou-se número de figuras de mitose em número semelhante com 36 horas (p=0,3528) e tendência a ser maior no grupo experimento com 7 dias (p=0,0883). A média de núcleos PCNA positivos foi maior no grupo experimento tanto com 36 horas (p=0,0009) quanto com 7 dias (p=0,0000). CONCLUSÃO: O hexaidrobenzoato de estradiol favoreceu a regeneração hepática em ratos submetidos à hepatectomia 70 por cento.(AU)

Validação de conjuntos diagnósticos comerciais para dosagem sérica de progesterona e estradiol em jaguatirica (Leopardus pardalis) e gato-do-matopequeno (Leopardus tigrinus) / Progesterone and estradiol commercial kits validation in serum of ocelots (Leopardus pardalis) and tigrina (Leopardus tigrinus)

Este estudo teve como objetivo validar os conjuntos diagnósticos m comerciais DPC (Coat-A-Count - Diagnostic Products Corporation/USA), em fase sólida, para dosagem de progesterona e DSL (Diagnostic System Laboratories INC/USA), em fase líquida, para dosagem de estradiol, por radioimunoensaio, em soro de Leopardus pardalis (n=5)e Leopardus tigrinus (n=4), antes (15-30 dias) e após (24-28 horas) tratamento com gonadotropinas exógenas (hCG/ Novormon® eeCG/ Vetecor®; pFSH/Folltropin-V® e pLH/Lutropin-V®). A concentração sérica para Leopardus pardalis variou 0,005 a 0,151ng/ml para estradiol e 0,15-37,22ng/ml para progesterona. A concentração sérica para Leopardus tigrinus variou 0,012-0,147ng/ml para estradiol e 0,06-34,09ng/ml para progesterona. A sensibilidade mínima detectada foi 0,004 ng/ml para progesterona e 0,00014ng/ml para estradiol. Para progesterona o coeficiente intra-ensaio baixo foi 2,58% e alto6,36%, já o coeficiente inter-ensaio baixo foi 0,67% e alto 5,55%. Para o estradiol o coeficiente intra-ensaio baixo foi 0,69% e alto 4,15%,sendo o coeficiente inter-ensaio baixo 1,40% e alto 3,00%. Paralelismo foi encontrado para progesterona e conjunto comercial DPC com r = 0,96 para Leopardus pardalis e r = 0,99 para Leopardus tigrinus. Para estradiol em conjunto comercial DSL paralelismo foi encontrado com r = 0,98 para Leopardus pardalis e com r = 0,99 para Leopardus tigrinus. Com estes resultados podemos concluir que o conjunto diagnóstico comercial DPC para dosagem de progesterona e DSL para dosagem de estradiol foram validados para utilização em soro de Leopardus pardalis e Leopardus tigrinus, podendo ser utilizado como ferramenta no manejo reprodutivo destas espécies visando à conservação.(AU)

DPC commercial kit (Coat-A-Count - Diagnostic Products Corporation/USA) and DSL commercial kit (Diagnostic System Laboratories INC/USA) were used for progesterone and estradiol radioimmunoassay validation in serum of two endangered Brazilian felids: Leopardus pardalis (n=5) and Leopardus tigrinus (n=4) before (15-30 days) and after (24-28 hours) exogenous gonadotrophins treatment(hCG/ Novormon® and eCG/ Vetecor®; pFSH/Folltropin-V® andpLH/Lutropin-V®). Variation of estradiol concentration was 0.005 -0.151 ng/ml and progesterone concentration was 0.15 - 37.22 ng/ml for Leopardus pardalis. Variation of estradiol concentration was 0.012 -0.147 ng/ml and progesterone concentration was 0.15 - 37.22 ng/ml for Leopardus tigrinus. Minimum sensibility detected for progesterone was 0.004 ng/ml and for estradiol was 0.00014 ng/ml. Progesterone intra-assay coefficient was 2.58% and 6.36% and inter-assay was 0.67% and 5.55%. Estradiol intra-assay coefficient was 0.69% and 4.15%,and inter-assay was 1.40% and 3.00%. Parallelism was used for kits validation. Progesterone and DPC commercial kit Parallelism wasr = 0.96 for Leopardus pardalis and r = 0.99 for Leopardus tigrinus. Estradiol and DSL commercial kit Parallelism was r = 0.98 for Leopardus pardalis and r = 0.99 for Leopardus tigrinus. In conclusion, these results showed that DPC commercial kit for serum progesterone dosages and DSL commercial kit for serum estradiol dosages can be used for Leopardus pardalis e Leopardus tigrinus. These findings are potentially valuable for the reproductive management and conservation of endangered felid populations.(AU)

Efeito do ambiente endócrino peri-ovulatório na expressão gênica e proteica de transportadores de glicose no endométrio durante a primeira semana do ciclo estral em bovinos de corte / Effect of the periovulatory endocrine milieu on endometrial glucose transporters gene and protein expression during the first week post-estrus in beef cattle

Em bovinos de corte, maiores diâmetros do folículo pré-ovulatório (FPO) e as subsequentes altas concentrações de progesterona [P4] aumentam o crescimento do concepto e a taxa de prenhez. Formulou-se a hipótese que a modulação do tamanho do FPO e [P4] no diestro subsequente à ovulação do FPO estimulam a expressão endometrial de transcritos e proteínas da famílias das Solute Carrier Proteins (SLC) que estão relacionadas ao transporte de glicose. Vacas Nelore (n=60), solteiras e ciclando receberam duas injeções de PGF2α (PGF; 0,5mg; i.m.) com intervalo de 14 dias. Dez dias após (dia -10; D-10), receberam um dispositivo intravaginal liberador de P4 e benzoato de estradiol (2mg; i.m.). Para modular o crescimento do FPO e alterar a produção de P4 pós-ovulação, no D-10 os animais receberam PGF (grupo alta P4; AP) ou não (grupo baixa P4; BP). Dispositivos foram removidos e PGF injetada 60 a 42 horas antes da indução da ovulação para o grupo AP e 48 a 30 horas antes da indução para o grupo BP e ovulações foram induzidas com GnRH (buserelina; 10µg; i.m.) no D0. Crescimento e ovulação do FPO e formação do CL foram avaliados por ultrassom e [P4] medidas por radioimunoensaio. No D7 os animais que ovularam foram abatidos (AP, N=18 e BP, N=18), o endométrio foi dissecado e submetido à extração de RNA total para análises de qPCR, extração de proteínas totais para análises de western blotting e incluído em parafina para análises de imunohistoquímica. Diferença entre as médias dos grupos foi determinada pelo teste t de student. [...] Em conclusão, a modulação do tamanho do FPO e [P4] no diestro não afetaram a expressão gênica ou proteica dos transportadores de glicose. É possível que ao invés da expressão gênica ou proteica, a atividade transportadora das SLCs, ou ainda, a expressão e função de genes relacionados ao metabolismo de carboidratos, sejam regulados pelo ambiente endócrino peri-ovulatório em vacas.

In beef cattle, changes in the peri-ovulatory endocrine milieu are associated with conceptus growth and fertility. A large size of the pre-ovulatory follicle (POF) and resulting elevated progesterone (P4) concentrations during diestrus affect pregnancy rates positively. Our hypothesis is that modulation of POF size and diestrus P4 concentrations regulate nutrient availability in the uterus. Specifically, optimal glucose concentrations in the histotroph are required for adequate embryo growth during early gestation. The objective was to determine if POF size and resulting P4 concentrations during the first week of diestrus influence gene expression of Solute Carrier Protein (SLC) families that are related to glucose transport. Cyclic, non-lactating Nelore cows received two injections of cloprostenol (PGF; 0.5mg; i.m.) 14 days apart. Ten days later (day -10; D-10), cows received a P4-releasing device along with estradiol benzoate (2mg; i.m.). To modulate the growth of the POF and alter post-ovulatory P4 production, on D-10 animals received PGF (high post-ovulatory P4 group; HP) or not (low post-ovulatory P4 group; LP). The P4-releasing devices were removed and PGF injected 60 to 42 hours before the ovulation induction in the HP group and 48 to 30 hours before the ovulation induction in the LP group. Ovulation was induced with buserelin (GnRH; 10µg; i.m.) on D0. Diameter of POF and ovulation were assessed by ultrasonography starting onD- 2. From D1 to D7, plasma was obtained for measurement of P4 concentration. [...] In conclusion, modulation of POF size and diestrus P4 concentrations did not affect the expression of glucose transporter genes or proteins. It is possible that activity of SLC proteins rather than gene expression, or alternatively, expression and function of genes related to carbohydrate metabolism, are regulated by the peri-ovulatory endocrine milieu in cows.

Efeito do ambiente endócrino peri-ovulatório na expressão gênica e proteica de transportadores de glicose no endométrio durante a primeira semana do ciclo estral em bovinos de corte / Effect of the periovulatory endocrine milieu on endometrial glucose transporters gene and protein expression during the first week post-estrus in beef cattle

Em bovinos de corte, maiores diâmetros do folículo pré-ovulatório (FPO) e as subsequentes altas concentrações de progesterona [P4] aumentam o crescimento do concepto e a taxa de prenhez. Formulou-se a hipótese que a modulação do tamanho do FPO e [P4] no diestro subsequente à ovulação do FPO estimulam a expressão endometrial de transcritos e proteínas da famílias das Solute Carrier Proteins (SLC) que estão relacionadas ao transporte de glicose. Vacas Nelore (n=60), solteiras e ciclando receberam duas injeções de PGF2α (PGF; 0,5mg; i.m.) com intervalo de 14 dias. Dez dias após (dia -10; D-10), receberam um dispositivo intravaginal liberador de P4 e benzoato de estradiol (2mg; i.m.). Para modular o crescimento do FPO e alterar a produção de P4 pós-ovulação, no D-10 os animais receberam PGF (grupo alta P4; AP) ou não (grupo baixa P4; BP). Dispositivos foram removidos e PGF injetada 60 a 42 horas antes da indução da ovulação para o grupo AP e 48 a 30 horas antes da indução para o grupo BP e ovulações foram induzidas com GnRH (buserelina; 10µg; i.m.) no D0. Crescimento e ovulação do FPO e formação do CL foram avaliados por ultrassom e [P4] medidas por radioimunoensaio. No D7 os animais que ovularam foram abatidos (AP, N=18 e BP, N=18), o endométrio foi dissecado e submetido à extração de RNA total para análises de qPCR, extração de proteínas totais para análises de western blotting e incluído em parafina para análises de imunohistoquímica. Diferença entre as médias dos grupos foi determinada pelo teste t de student. [...] Em conclusão, a modulação do tamanho do FPO e [P4] no diestro não afetaram a expressão gênica ou proteica dos transportadores de glicose. É possível que ao invés da expressão gênica ou proteica, a atividade transportadora das SLCs, ou ainda, a expressão e função de genes relacionados ao metabolismo de carboidratos, sejam regulados pelo ambiente endócrino peri-ovulatório em vacas. (AU)

In beef cattle, changes in the peri-ovulatory endocrine milieu are associated with conceptus growth and fertility. A large size of the pre-ovulatory follicle (POF) and resulting elevated progesterone (P4) concentrations during diestrus affect pregnancy rates positively. Our hypothesis is that modulation of POF size and diestrus P4 concentrations regulate nutrient availability in the uterus. Specifically, optimal glucose concentrations in the histotroph are required for adequate embryo growth during early gestation. The objective was to determine if POF size and resulting P4 concentrations during the first week of diestrus influence gene expression of Solute Carrier Protein (SLC) families that are related to glucose transport. Cyclic, non-lactating Nelore cows received two injections of cloprostenol (PGF; 0.5mg; i.m.) 14 days apart. Ten days later (day -10; D-10), cows received a P4-releasing device along with estradiol benzoate (2mg; i.m.). To modulate the growth of the POF and alter post-ovulatory P4 production, on D-10 animals received PGF (high post-ovulatory P4 group; HP) or not (low post-ovulatory P4 group; LP). The P4-releasing devices were removed and PGF injected 60 to 42 hours before the ovulation induction in the HP group and 48 to 30 hours before the ovulation induction in the LP group. Ovulation was induced with buserelin (GnRH; 10µg; i.m.) on D0. Diameter of POF and ovulation were assessed by ultrasonography starting onD- 2. From D1 to D7, plasma was obtained for measurement of P4 concentration. [...] In conclusion, modulation of POF size and diestrus P4 concentrations did not affect the expression of glucose transporter genes or proteins. It is possible that activity of SLC proteins rather than gene expression, or alternatively, expression and function of genes related to carbohydrate metabolism, are regulated by the peri-ovulatory endocrine milieu in cows. (AU)

Taxas de serviço, concepção e prenhez de vacas nelore tratadas com gonadotrofina coriônica humana e 17β estradiol após a inseminação artificial em tempo fixo / Service, conception and pregnancy rates of nelore cows treated with human corionic gonadotropin and estradiol-17β after timed artificial insemination

Avaliaram-se estratégias para reduzir a mortalidade embrionária em bovinos. Vacas Nelore (Bos taurus indicus) foram inseminadas em tempo fixo (IATF - D0) após o protocolo GnRH/PGF2a/GnRH e divididas nos grupos: Controle (Gc; n=55), hCG (GhCG; n=55) recebeu 3000 UI da hCG no D5 , E2 (GE2; n=55) recebeu 5 mg de 17?-Estradiol (E2) no D12 e hCG/E2 (GhCG/E2; n=55) recebeu 3000 UI da hCG no D5 e 5mg do E2 no D12. A IATF foi o 1o dia da estação de reprodução de 64 dias. Usou-se o teste do c2 para comparar as taxas de serviço (TS), concepção (TC) e prenhez à IATF (TPIATF), às IAs de repasse e acumuladas. A TS e a TC das IAs de repasse não diferiu (P>0,10). Houve diferenças nas TPIATF (P<0,05), pois a TPIATF do GE2 (5,4%) foi a mais baixa e a do Gc (34,5%) e GhCG (36,5%) tenderam (P<0,10) ser maiores que a do GhCG/E2 (18,2%). Não houve efeito da hCG sobre as taxas de prenhez. O E2 reduziu a TPIATF e ao final da estação as vacas que receberam o E2 (GE2 + GhCG/E2) tiveram TPacum (66,4%) mais baixa (P<0,05) de que aquelas (80,9%) que não receberam (GC + GhCG). Em conclusão, as estratégias adotadas de manipulação luteínica ou folicular não aumentaram as taxas de prenhez em vacas Nelore após uma IATF.(AU)

Strategies to reduce embryo mortality in cattle have been evaluated. Nelore (Bos taurus indicus) cows were submitted to timed artificial insemination (TAI - D0) after a GnRH/PGF2a/GnRH protocol. Cows were divided in the following groups: Control (Gc; n=55), hCG (GhCG; n=55) received 3000 IU of hCG on D5 , E2 (GE2; n=55) received 5 mg of Estradiol-17b (E2) on D12 and hCG/E2 (GhCG/E2; n=55) received hCG on D5 and E2 on D12. TAI represented the 1st day of a 64 day breeding season. The c2 test was applied to compare mating rate (MR), conception rate (CR) and pregnancy rate (PR) to TAI and AIs after natural estrus within the season as well as their accumulated figures at the end of the season. MR and CR for AIs within season did not differ (P>.10). PR to TAI differed (P<.05) among groups. GE2 showed the lowest rate (5,4%). Gc (34.5%) and GhCG (36.5%) tended (P<.10) to be higher than GhCG/E2 (18.2%). There was no effect of hCG on pregnancy rates. E2 reduced PR to TAI and at the end of season which means that cows receiving E2 (GE2 + GhCG/E2) had lower (66.4%; P<.05) PR than cows not receiving E2 (GC + GhCG; 80.9%). In conlusion, the strategies to manipulate luteal and follicular function herein tested did not increase pregnancy rates in Nelore cows submitted to a TAI.(AU)

Tumores da mama em cadelas: estudo dos níveis séricos de estradiol E-2 e progesterona associados à histopatologia

Os tumores da mama constituem aproximadamente 50% dos tumores diagnosticados em cadelas. Apesar dos hormônios sexuais femininos desempenharem papel fundamental no desenvolvimento desses tumores em mamíferos, o valor da supressão hormonal pela ovário-histerectomia como auxiliar no tratamento do tumor de mama em caninos permanece controverso. O objetivo desta pesquisa é discutir alguns aspectos relacionados à influência hormonal na etiologia de tumores mamárias em cadelas, assim como o valor terapêutico da castração, quando realizada no momento da mastectomia.

The mammary neoplasms comprises aproximatel 50% ofthe diagnosed tumors in the bitch. Although female sexual honnones play a fundamental role in the development of these tumors in mammals, the value of the suppression hormonal (ovariohysterectomy) as an adjuvam treatment remains controversial. The objective ofthis review is to discuss some aspects related to the hormonal influence in the pathogenesis of the canine tumor, as well as the therapeutic value ofspaying. when accomplished in the moment ofthe mastectomy.

Tumores da mama em cadelas: estudo dos níveis séricos de estradiol E-2 e progesterona associados à histopatologia

Os tumores da mama constituem aproximadamente 50% dos tumores diagnosticados em cadelas. Apesar dos hormônios sexuais femininos desempenharem papel fundamental no desenvolvimento desses tumores em mamíferos, o valor da supressão hormonal pela ovário-histerectomia como auxiliar no tratamento do tumor de mama em caninos permanece controverso. O objetivo desta pesquisa é discutir alguns aspectos relacionados à influência hormonal na etiologia de tumores mamárias em cadelas, assim como o valor terapêutico da castração, quando realizada no momento da mastectomia.(AU)

The mammary neoplasms comprises aproximatel 50% ofthe diagnosed tumors in the bitch. Although female sexual honnones play a fundamental role in the development of these tumors in mammals, the value of the suppression hormonal (ovariohysterectomy) as an adjuvam treatment remains controversial. The objective ofthis review is to discuss some aspects related to the hormonal influence in the pathogenesis of the canine tumor, as well as the therapeutic value ofspaying. when accomplished in the moment ofthe mastectomy.(AU)

Controle da síntese de prostaglandina F2 ALFA no endométrio bovino in vitro / In vitro control of prostaglandin F2a synthesis in bovine endometrium

A síntese de prostaglandina F2± (PGF2±) endometrial, resulta de uma complexa cascata de eventos intracelulares que ocorrem de maneira altamente coordenada. A síntese de PGF2± pode ser estimulada na presença da melitina e do forbol 12,13 dibutirato (PDBu). O objetivo do presente estudo foi verificar se a produção basal e a estimulação aguda de PGF2± são dependentes da síntese de proteínas. No experimento 1, explantes obtidos de fêmeas bovinas (n=2), cíclicas, não lactantes, no dia 15 do ciclo estral foram incubados em quadruplicata, com meio de cultivo (KHB) ou KHB suplementado com PDBu 10-6M, melitina 10-6M ou melitina 10-5M. Amostras do meio foram coletadas 0 e 60 minutos após os tratamentos e as concentrações de PGF2± foram mensuradas por radioimunoensaio. Com 60 minutos após os tratamentos houve aumento das concentrações médias de PGF2± (P<0,06) em resposta ao tratamento com PDBu comparado ao grupo KHB e melitina. No experimento 2, explantes endometriais de fêmeas bovinas (n=4), não gestantes, no 17° dia do ciclo estral, pesando de 80 a 100mg foram incubados em KHB suplementado com 0, 50, 100 ou 200mg/mL de CHX e 0 ou 100ng/mL de PDBu em um arranjo fatorial 2 x 4, em quadruplicata. Amostras do meio foram coletadas 0 e 60 minutos após os tratamentos e as concentrações de PGF2± foram mensuradas por radioimunoensaio. A integridade dos explantes endometriais tratados com CHX foi avaliada por cortes histológicos. Foi observado aumento na produção de PGF2± em resposta ao tratamento com PDBu (P<0,01), entretanto, não houve diferenças na produção de PGF2± pelos tecidos tratados com diferentes concentrações de CHX, associadas ou não ao PDBu. A integridade histológica dos explantes foi preservada. Conclui-se que a produção basal e a estimulação aguda da síntese de PGF2± não são dependentes da síntese de novas proteínas. (AU)

Synthesis of endometrial prostaglandin F2a (PGF2a) results from acomplex cascade of highly coordinated intracellular events. Productionof PGF2a can be stimulated by mellitin and 12, 13 phorbol dibutyrate(PDBu). Objective of the present study was to verify whether basalor stimulated synthesis of PGF2a was dependent on de novo proteinsynthesis. In Experiment 1, endometrial explants from cyclic, nonlactating cross-bred beef cows (n=2) on day 15 of the estrous cyclewere incubated in quadruplicate in culture KHB culture medium ormedium supplemented with 10-6M PDBu, 10-6M melittin or 10-5Mmelittin. Medium samples were collected immediately and 60 minutesafter treatment administration and concentration of PGF2a in mediumwere measured by radioimmunoassay. Concentrations of PGF2a inmedium were higher (P<0.06) after treatment with PDBu incomparison with control and melittin. In Experiment 2, endometrialexplants from cyclic, non-lactating cross-bred beef cows (n=4) on day17 of the estrous cycle were incubated in quadruplicate in mediumsupplemented with 0, 50, 100 or 200mg cyclohexamide (CHX) and 0or 100ng/ml PDBu, in a 4 x 2 factorial arrangement. Medium sampleswere collected immediately and 60 minutes after administration oftreatments and concentrations of PGF2a measured byradioimmunoassay. Endometrial integrity was was evaluated byhistology. Treatment with PDBu stimulated production of PGF2a(P<0.01), regardless of concentration of CHX used. The CHX didnot affect production of PGF2a, either in the presence or absence ofPDBu. Histological integrity of explants was preserved. It wasconcluded that both basal and PDBu-stimulated PGF2a productionare not dependent on new protein sythesis. (AU)

Concentrações hormonais e desenvolvimento folicular de vacas leiteiras em hipertermia sazonal e aguda / Hormone concentration and follicular development in dairy cows under seasonal and acute hyperthermia

Avaliaram-se as concentrações hormonais e os parâmetros de desenvolvimento folicular de vacas leiteiras expostas ao calor sazonal e agudo. Dividiram-se os animais em quatro grupos: verão (n=5), outono (n=5), inverno com hipertermia aguda (grupo câmara climática, (CC), n=5) e inverno (n=9). Os animais foram abatidos no sétimo dia após a ovulação, e os parâmetros de desenvolvimento folicular avaliados. O líquido folicular do maior folículo foi aspirado e armazenado para posterior análise de hormônios esteróides e inibina. O número de células da granulosa vivas no verão e no outono foi 40 e 45% respectivamente, menor que no inverno (P<0,05). A concentração de estradiol (E2) no inverno foi 62% maior que no outono (P<0,05) e 34% superior ao grupo verão (P<0,06). Houve um aumento na quantidade de androstenediona no verão em relação aos grupos inverno (P<0,08) e outono (P<0,05). A concentração de inibina foi maior no inverno do que no verão e CC (P<0,05). A exposição ao calor sazonal e agudo modificou os parâmetros de desenvolvimento do folículo e as concentrações hormonais no líquido folicular, podendo explicar em parte a queda nas taxas de concepção no verão.(AU)

The present study evaluated the seasonal and acute heat stress on follicular development and steroid and inhibin concentrations in follicular fluid, in bovine dominant follicle. Cows were distributed into four treatments: summer (n=5), autumn (n=5), animals heat stressed during the winter (n=5) and winter (n=9). On day 7 of the estrous cycle, animals were slaughtered and parameters related to follicle development were evaluated. The follicular fluid (FF) was aspirated and stored for further hormonal analysis. During the summer, the number of viable granulosa cells was 40% lower than during the winter, and there was a 45% decrease in this parameter during the autumn (P<0.05). In the winter, estradiol concentration was 62% higher than during the autumn (P<0.05) and 42% higher than during the summer (P<0.06). There was an increase in androstenedione concentration in summer group, when compared to winter (P<0.08) and autumn (P<0.05) groups. Inhibin concentration was higher in winter groups than summer and winter heat stressed groups (P<0.05). Seasonal and acute heat stress altered developmental parameters in dominant follicle and hormonal concentration in follicular fluid, those effects can partially explain the decrease in conception rates during summer.(AU)