Sex steroid receptors in the ovarian follicles of the lizard Sceloporus torquatus.

Estradiol and progesterone have been recognized as important mediators of reproductive events in the female mainly via binding to their receptors. This study aimed to characterize the immunolocalization of the estrogen receptor alfa (ERα), estrogen receptor beta (ERß) and progesterone receptor (PR) in the ovarian follicles of the lizard Sceloporus torquatus. The localization of steroid receptors has a spatio-temporal pattern that depends on the stage of follicular development. The immunostaining intensity of the three receptors was high in the pyriform cells and the cortex of the oocyte of previtellogenic follicles. During the vitellogenic phase, the granulosa and theca immunostaining was intense even with the modification of the follicular layer. In the preovulatory follicles, the receptors were found in yolk and additionally, ERα was also located in the theca. These observations suggest a role for sex steroids in regulating follicular development in lizards, like other vertebrates.

Sex steroids are correlated with environmental factors and body condition during the reproductive cycle in females of the lizard Sceloporus torquatus.

Reproduction is regulated by multiple factors that influence physiology and behavior to ensure the continuity of species. However, more work is needed to examine the complex relationships between environmental factors and endocrine transducers that modulate reproductive cycles, particularly in lizards. Here, we aimed to characterize the variation in plasma sex steroid levels in different stages of the reproductive cycle in the lizard Sceloporus torquatus and assess whether sex steroid levels were related to environmental factors (temperature, photoperiod, precipitation, and relative humidity) and body condition. Plasma concentrations of estradiol (E2) and progesterone (P4) from blood samples were quantified by enzyme-linked immunosorbent assay (ELISA) and radioimmunoanalysis (RIA), respectively. Our results indicate that sex steroid concentrations were positively related to follicular development but negatively related to temperature and precipitation. E2 increased as the follicles grew, and its concentrations were highest in the preovulatory phase. P4 showed a similar pattern and persisted during pregnancy. Changes in body condition were non-significant and mainly unrelated to the reproductive stage and plasma sex steroids. Our findings indicate that sex steroids change depending on the season and reproductive stage. We observed high concentrations of E2 and P4 in the late vitellogenic and preovulatory stages, probably because of their role in promoting vitellogenesis and ovulation. Additionally, we observed that follicular development is correlated with temperature and photoperiod. To better understand the mechanisms underlying reproduction, future studies of captive populations where environmental factors can be manipulated are needed.

Territorial aggression by dwarf hamster females (Phodopus campbelli): A hormonal approach.

Females of many vertebrate species are territorial. However, few studies have been performed on territorial aggression and its hormonal bases in females. The present study determined whether dwarf hamster females (Phodopus campbelli) display territorial aggression and the role that estradiol (E2 ) and progesterone (P4 ) play in this behavior. Two experiments were carried out. First, 28 virgin females were mated with sexually inexperienced males. The females were submitted to oviduct ligation 2 weeks before mating to prevent pregnancy. After 15 days of mating, 16 out of 28 females were submitted to resident-intruder tests, whereas the remaining 12 females were nonconfronted. Blood samples were collected 30 min after the aggression tests to determine E2 and P4 by ELISA. In the second experiment, 40 females were mated with vasectomized males. Thirty days after mating, 30 dwarf hamsters were subjected to ovariectomy; 10 were nontreated, 10 were treated with E2 , and 10 with P4 . The remaining 10 were sham-operated. All females were submitted to resident-intruder tests, and blood samples were taken to quantify E2 and P4 . In the first experiment, 87.5% of dwarf hamster females displayed territorial aggression, and in the second, 100% of females were aggressive. Ovariectomy and ovariectomy plus E2 or P4 replacement did not affect aggressive territorial behavior. These results showed that this species' females are territorial, and this behavior is not dependent on ovarian steroid hormones.

Testosterone dependent territorial aggression is modulated by cohabitation with a female in male Mongolian gerbils (Meriones unguiculatus).

Most mammal studies on the neuroendocrine mechanisms of territorial aggression have demonstrated that testosterone (T) is required for the display of territorial aggression. However, the relationship between T and aggression is more complex and may be modulated by social factor. The aim of this study was to determine the role of T in territorial aggression in the Mongolian gerbil (Meriones unguiculatus), and the effect of social factors on the modulation of this behavior. The relationship between T and territorial aggression was analyzed using castration and T replacement in two social contexts: male-male and male-female cohabitation. Plasma T concentrations in males of all groups were quantified by radioimmunoassay (RIA). T concentrations were compared using two-way ANOVA. Only sham-castrated and castrated males with T replacement in male-female cohabitation showed aggression, whereas castrated gerbils in the same condition were not aggressive. This indicates that T is the hormone that maintains territorial aggression, but mating is a modulator stimulus. The modulator effect of mating in territorial aggression was associated with an increase in T, but it seems that other mechanisms are involved in the regulation of this behavior, since castrated males with T replacement in the male-male cohabitation did not exhibit aggression, although they had T concentrations as high as these males that received the same treatment, but that cohabited with a female. These results suggest that T is involved in the mechanisms that regulate territorial aggression in the male Mongolian gerbil, and that the cohabitation with a female modulates this behavior.

Coffee pulp supplementation prior to breeding improves oxidative status without affecting fertility of primiparous ewes / La suplementación con pulpa de café antes de la monta mejora el estado oxidativo sin afectar la fertilidad de ovejas primiparas / A suplementação de polpa de café antes da reprodução melhora o estado oxidativo sem afetar a fertilidade de ovelhas primíparas

Abstract Background: Coffee pulp has a high content of antioxidants capable of modifying the oxidative status in small ruminants. However, high amounts for a prolonged time can reduce fertility. Objective: To determine the effect of two inclusion levels of coffee pulp during estrous synchronization on reproductive variables and oxidative status of primiparous ewes. Methods: Sixty Suffolk x Dorset primiparous ewes were distributed into three treatments in a completely randomized design; T0: (n=20) 1.5 kg balanced diet, T1: (n=20) 1.5 kg balanced diet and 5% coffee pulp, T2: (n=20) 1.5 kg balanced diet and 10% coffee pulp. Supplementation was given for 16 days before estrus synchronization and until the beginning of the breeding season. A progestogen (CIDR®) was inserted for 11 days and a dose of PGF2α was applied two days prior to its withdrawal. Estrus detection started 12 hours after CIDR withdrawal. Blood samples were obtained during the supplementation period to measure oxidative status, antioxidant capacity, glucose and insulin, and up to 9 days after breeding to determine progesterone concentration. Pregnancy diagnosis was performed at 30 and 60 days post-breeding. An analysis of repeated measures of mixed effects and frequency analysis were carried out. Results: Inclusion of coffee pulp for a short period prior to breeding did not affect reproductive parameters, nor progesterone, glucose or insulin concentrations (p>0.05); however, antioxidant capacity increased, while lipid oxidation showed an opposite trend (p<0.05). Conclusion: Inclusion of up to 10% coffee pulp in the diet of ewe lambs for 16 days prior to breeding improves oxidative status without causing adverse effects on pregnancy, estrus or prolificacy.

Resumen Antecedentes: La pulpa de café tiene un alto contenido de antioxidantes capaces de modificar el estado oxidativo en pequeños rumiantes. Sin embargo, a dosis elevadas y por un tiempo prolongado puede reducir la fertilidad. Objetivo: Determinar el efecto de dos niveles de inclusión de pulpa de café durante la sincronización del estro en variables reproductivas y el estado oxidativo de ovejas primerizas. Métodos: Se utilizaron 60 ovejas primalas Suffolk x Dorset fueron distribuidas en tres tratamientos en un diseño completamente al azar; T0: (n=20) con 1,5 kg de dieta integral, T1: (n=20) con 1,5 kg de dieta integral y 5% de pulpa de café, T2: (n=20) con 1,5 kg de dieta integral y 10% de pulpa de café. La suplementación se realizó por 16 días, previo a la sincronización del estro y hasta el empadre. El progestágeno (CIDR®) se insertó en las ovejas por 11 días y se aplicó una dosis de PGF2α dos días antes de su retiro. La detección de estro comenzó a las 12 horas post-retiro del CIDR®. Se obtuvieron muestras sanguíneas durante el periodo de suplementación para medir estado oxidativo, capacidad antioxidante, glucosa e insulina, y hasta 9 días posteriores al empadre para determinar las concentraciones de progesterona. El diagnóstico de gestación se realizó a los 30 y 60 días post-monta. Se realizaron análisis de medidas repetidas utilizando un modelo de efectos mixtos, además de análisis de frecuencias. Resultados: La inclusión de pulpa por un periodo corto previo al empadre no afectó los parámetros reproductivos ni las concentraciones de progesterona, glucosa o insulina (p>0,05); sin embargo, la capacidad antioxidante se incrementó, mientras que la oxidación lipídica siguió una tendencia inversa (p<0,05). Conclusión: La inclusión hasta de 10% de pulpa de café en la dieta de ovejas por 16 días previo al empadre mejora el estado oxidativo sin ocasionar efectos adversos en el porcentaje de preñez, estro o prolificidad.

Resumo Antecedentes: A polpa de café tem alto conteúdo de antioxidantes capazes de modificar o estado oxidativo em pequenos ruminantes; no entanto, em doses elevadas e por um tempo prolongado reduz a fertilidade. Objetivo: Determinar o efeito de diferentes níveis de inclusão de polpa de café durante a sincronização do estro em diferentes variáveis reprodutivas e estado oxidativo das ovelhas primíparas. Métodos: Sessenta ovelhas primíparas dos cruzamentos Suffolk x Dorset foram distribuídas em três tratamentos em um design completamente aleatório; T0: (n=20) com 1,5 kg de dieta completa, T1: (n=20) com 1,5 kg de dieta completa contendo 5% de polpa de café, T2: (n=20) com 1,5 kg de dieta completa contendo 10% de polpa de café. A suplementação realizou-se por 16 dias, antes do início da sincronização de estros e até o momento do acasalamento. O progestogênio (CIDR) foi inserido nas ovelhas durante 11 dias e uma dose de PGF2α foi aplicada dois dias antes da sua retirada. Doze horas após a retirada do CIDR iniciou-se a detecção de estros. Foram obtidas amostras de sangue durante o período de suplementação, para medição do estado oxidativo, capacidade antioxidante, glicose e insulina e até 9 dias posteriores ao início da estação de monta para determinar as concentrações de progesterona. O diagnostico de gestação realizou-se aos 30 e 60 dias post-monta. Uma análise de medidas repetidas de efeitos mistos e análise de freqüência foi realizada. Resultados: A inclusão de polpa por um período curto antes da estação de monta não afetou os parâmetros reprodutivos nem as concentrações de progesterona, glicose e insulina (p>0,05); porém, a capacidade antioxidante nas ovelhas foi aumentada, enquanto a oxidação lipídica seguiu uma tendência inversa (p<0,05). Conclusão: Inclusão de polpa de café na dieta de ovelha até 10% durante 16 dias antes do acasalamento melhora o estado oxidativo, sem causar efeitos adversos na porcentagem de gravidez, estro e prolificidade.

Does the conceptus of the viviparous lizard Barisia imbricata imbricata participates in the regulation of progesterone production and the control of luteolysis?

It is generally accepted that progesterone is necessary to maintain gestation; however, the mechanisms that control the production of this steroid remain unknown. The corpus luteum has been assigned a central role in the maintenance of gestation based on its capacity to produce progesterone. A pseudopregnancy model was performed in a viviparous lizard, Barisia imbricata imbricata, to determine whether the absence of embryos would affect the pattern of progesterone production or the corpus luteum histology. Blood samples were obtained prior to ovulation and at 8, 16, and 24 weeks after ovulation (pseudopregnant and pregnant lizards), as well as one day after parturition (pregnant lizards) or 32 weeks after ovulation (pseudopregnant lizards). The corpus luteum was surgically removed one day after blood samples were obtained. Blood aliquots from nongravid females were obtained at similar timepoints. We found a significant reduction in plasma progesterone concentrations at 24 and 32 weeks post-ovulation in pseudopregnant lizards compared with those observed at similar times in intact pregnant lizards, whereas the progesterone levels in non-gestant lizards remained significantly lower than in either pseudopregnant or pregnant lizards. Moreover, we observed that the histological appearance of the corpus luteum from pseudogestational females (obtained 24 and 32 weeks post-ovulation) differed from the corpora lutea from lizards in late gestation and intact parturient lizards. These observations suggest that the conceptus participates in the regulation of progesterone production in late gestation and also in luteolysis control.

Effects of luteectomy in early pregnancy on the maintenance of gestation and plasma progesterone concentrations in the viviparous temperate lizard Barisia imbricata imbricata.

BACKGROUND: Several studies have shown that the corpus luteum is the principal source of progesterone during the gravidity period in reptiles; however, its participation in the maintenance of gestation in the viviparous squamata is in dispute. The effects of ovariectomy or luteectomy vary according to the species and the time at which the procedure is performed. In this paper, we describe the effects of luteectomy during early pregnancy on the maintenance of gestation and progesterone concentrations in the temperate Mexican viviparous lizard Barisia imbricata imbricata. METHODS: Twenty-four lizards were subjected to three different treatments: luteectomy, sham luteectomy or non-surgical treatment, and blood samples were obtained before and after surgical treatment at different stages of gestation to determine the effects of luteectomy on the maintenance of gestation and progesterone concentrations. RESULTS: Spontaneous abortion was not observed in any of the females. However, luteectomy provoked abnormal parturition and a significant reduction in the number of young born alive. Parturition was normal in untreated females as well as those submitted to sham luteectomy. The surgical treatment also caused a significant reduction in progesterone concentrations in luteectomised females during early and middle gestation. However, no significant differences in hormone concentrations were observed among the three groups during late gestation or immediately post-parturition. CONCLUSIONS: Our observations indicate that the presence of the corpus luteum is not necesary for the maintenance of gestation, but that it does participate in parturition control. Moreover, the corpus luteum of the viviparous lizard B. i. imbricata produces progesterone, at least during the first half of pregnancy, and that an extra-ovarian source of progesterone must maintain gestation in the absence of luteal tissue.

[Levels of estradiol and serum testosterone in healthy postmenopausal women and its relationship with symptoms]. / Concentraciones de estradiol y testosterona en suero de mujeres climatéricas y su relación con los síntomas.

BACKGROUND: Several studies have tried to evaluate in which estradiol (E2) and testosterone (T) levels the climacteric symptoms appear, but this has not been possible at all. OBJECTIVE: To evaluate in which E2 and T levels climacteric symptoms appear, as well as its relation with T/E2 ratio. MATERIAL AND METHODS: Twenty nine healthy climacteric women [perimenopausal (n = 13) or postmenopausal (n = 16)] which have not received nor were receiving hormone therapy were studied. Age, body mass index, waist hip ratio and menstrual status were documented. An analog visual scale was used to evaluate the intensity of 13 climacteric symptoms. A blood sample was taken for the measurement of E2 and T measurement by radioimmunoassay. Pearson's correlation analysis was done between the sum of scores of all climacteric symptoms and with the score obtained from each of the climacteric symptoms and E2, T levels and T/E2 ratio. All patients gave their consent to participate in the study. RESULTS: The average age of women was 49.9 +/- 5.1 years and the time since menopause 43.9 +/- 53.2 months. The sum of the magnitudes of the symptoms was 71.2 +/- 24.9. The average level of E2 and T was 65.5 +/- 101.1 pg/ml and 14.5 +/- 10.7 ng/ml respectively. No correlation was observed between the sum of the magnitudes of the symptoms neither with the magnitude of each symptom with E2 and T levels and T/E2 ratio. CONCLUSIONS: It was not possible to determine with precision in which E2 and T levels climacteric symptoms appear and T/E2 ratio also was not useful for this purpose.

[Glycation and protein crosslinking in the diabetes and ageing pathogenesis]. / Glicación y entrecruzamiento de proteínas en la patogénesis de la diabetes y el envejecimiento.

Long exposition to hyperglycemia is associated with development of vascular diseases in diabetic patients. Many of these effects are mediated by non-enzymatic glycosylation (glycation) of proteins and formation of advanced glycation end-products (AGEs). This phenomenon is accelerated in conditions where glucose concentration is chronically high, as it happens in diabetes mellitus. AGE formation is associated with structure-function alterations of proteins such as collagen, and particularly in tissues where these products are accumulated. A number of studies have demonstrated that AGEs can act as mediators, not only for the development of chronic complications of diabetes, but also in those related to ageing, nephropathy, Alzheimer's disease and erectile dysfunction, among others. In this paper, information generated about formation and accumulation of AGEs, including its biological effects and their participation in the development of complications in diabetes mellitus and other process such as ageing is revised. In addition, therapeutic strategies and a new methodology to measure glycation products are also considered.

Glycation does not modify bovine serum albumin (BSA)-induced reduction of rat aortic relaxation: the response to glycated and nonglycated BSA is lost in metabolic syndrome.

The effects of nonglycated bovine serum albumin (BSA) and advanced glycosylation end products of BSA (AGE-BSA) on vascular responses of control and metabolic syndrome (MS) rats characterized by hypertriglyceridemia, hypertension, hyperinsulinemia, and insulin resistance were studied. Albumin and in vitro prepared AGE-BSA have vascular effects; however, recent studies indicate that some effects of in vitro prepared AGEs are due to the conditions in which they were generated. We produced AGEs by incubating glucose with BSA for 60 days under sterile conditions in darkness and at 37 degrees C. To develop MS rats, male Wistar animals were given 30% sucrose in drinking water since weanling. Six month old animals were used. Blood pressure, insulin, triglycerides, and serum albumin were increased in MS rats. Contraction of aortic rings elicited with norepinephrine was stronger. There were no effects of nonglycated BSA or AGE-BSA on contractions in control or MS rats; however, both groups responded to L-NAME, an inhibitor of nitric oxide synthesis. Arterial relaxation induced using acetylcholine was smaller in MS rats. Nonglycated BSA and AGE-BSA significantly diminished relaxation in a 35% in the control group but the decrease was similar when using nonglycated BSA and AGE-BSA. This decrease was not present in the MS rats and was not due to increased RAGEs or altered biochemical characteristics of BSA. In conclusion, both BSA and AGE-BSA inhibit vascular relaxation in control artic rings. In MS rats the effect is lost possibly due to alterations in endothelial cells that are a consequence of the illness.