[Individual hormonal profiles of blood progesterone and estradiol-17ß during the course of a reproductive cycle in mares]. / Individueller Konzentrationsverlauf von Progesteron und Östradiol-17ß im Blut bei Stuten während des Zyklus.

OBJECT AND AIM: This study presents the individual course of estradiol-17ß and progesterone concentrations in blood during the reproductive cycle in mares in order to point out physiological differences between individual animals and to aid in the interpretation of hormone values. MATERIAL AND METHODS: Concentrations of estradiol-17ß and progesterone were determined in seven mares over the course of their cycle. One mare was excluded from the study due to a physiologically deviating cycle. In addition, the mares' ovaries were examined via ultrasound on a daily basis in order to match the hormone values to morphological changes of the ovaries. RESULTS: In some cases, the mares showed considerable individual differences in their hormone concentrations, which also differed from the published comparative values in the literature. For example, two mares showed progesterone levels above basal levels at the time of ovulation. The postovulatory progesterone concentrations of the mares are characterized by marked fluctuations, which makes it difficult to provide reference values in the different sections of the corpus luteum phase. The length of the plateau phases averaged 12.3±1.5 days. The mare with double ovulation showed the highest progesterone concentrations. CONCLUSION: The measurement of plasma progesterone levels in mares should be interpreted only in the context of other test results. The very wide variation in estradiol-17ß concentrations makes it questionable whether the determination of this hormone value is of diagnostic value. CLINICAL RELEVANCE: When interpreting steroid hormone values in the ingravid cycle of a mare, the individual concentration courses must be taken into consideration, as they may deviate significantly from the published reference values.

Plasma concentration of progesterone and 17ß-estradiol of black-rumped agouti (Dasyprocta prymnolopha) during the estrous cycle

Plasma concentration of progesterone and 17β-estradiol of black-rumped agouti (Dasyprocta prymnolopha) during the estrous cycle. The agouti is a game animal that have been raised in captivity for conservation and sustainability purposes. However, the management of wild animals in an intensive breeding system requires an assertive knowledge of its reproductive parameters, one of the most important features for production improvement. Besides, little information is available regarding changes in reproductive hormone profiles in agouti. The objective of this study was to evaluate the hormonal profile of progesterone and 17β-estradiol during the estrous cycle of the agouti (Dasyprocta prymnolopha). The hormones were analyzed by radioimmunoassay. Blood samples were collected without sedation twice a week. The concentrations of progesterone were as follows: proestrus 0.78+0.39ng/ml, estrus 2.83+2.34ng/ml, metestrus 1.49+1.24ng/ml, diestrus 3.71+1.48ng/ml. In the estrous phase, an increase in the progesterone level was observed during a period of 24h. The average 17 β-estradiol levels were as follows: proestrus 2 030.98+961.00pg/ml, estrus 1 910.56+650.54pg/ml, metestrus 1 724.83+767.28pg/ml, diestrus 1 939.94+725.29pg/ml. The current results suggest that the progesterone plasma concentration during the estrous cycle in the agouti has a similar increasing, stabilizing and decreasing pattern, as in domestic mammals. Agoutis have two phases of follicular development, as two periods of 17β-estradiol peaks were observed, the first one in the metestrus and the second during the proestrus. Spontaneous ovulation seems to occur after the progesterone peak, possibly indicating that this hormone is associated with the ovulatory process. A more detailed investigation is needed for better understanding of how progesterone influences ovulation. Studies on the involvement of progesterone in follicular rupture can be carried out, using steroid biosynthesis inhibitors and observing the effect of this hormone on ovarian activity of proteolytic enzymes in the follicular wall. Rev. Biol. Trop. 59 (1): 29-35. Epub 2011 March 01.

El conocimiento de los procesos reproductivos de especies de importancia económica local son indispensables para apoyar su producción en cautiverio y garantizar su manejo sostenible. El objetivo del presente trabajo fue evaluar los niveles hormonales de progesterona y 17β-estradiol durante el ciclo estral en agutí (Dasyprocta prymnolopha). La recolección de sangre se realizó dos veces por semana, sin sedación. Las hormonas fueron analizadas por radioinmunoanálisis. Los niveles de progesterona fueron los siguientes: proestro 0.78+0.39ng/ml, estro 2.83+2.34ng/ml, metaestro 1.49+1.24ng/ml y diestro 3.71+1.48ng/ml. En el estro se observó un aumento de los niveles de progesterona durante un periodo de 24h. Los niveles de 17 β-estradiol fueron los siguientes: proestro 2 030.98+961.00pg/ml, estro 1 910.56+650.54pg/ml, metaesto 1 724.83+767.28pg/ml y diestro 1 939.94+725.29pg/ ml. Los resultados encontrados sugieren que los niveles plasmáticos de progesterona durante el ciclo estral en agutí siguen un patrón de aumento, estabilización y diminución, tal como en los mamíferos domésticos. Agutí tienen dos etapas de desarrollo folicular, puesto que se observaron dos altos valores de 17β-estradiol, el primero en el metaestro y el segundo durante el proestro. La ovulación espontánea ocurre posiblemente después del aumento de la progesterona, indicando que esta hormona posiblemente está asociada con el proceso ovulatorio. Es necesario desarrollar un estudio más detallado para mejorar la comprensión del papel de la progesterona en la ovulación. Algunos estudios de la participación de la progesterona en la ruptura folicular se pueden realizar utilizando inhibidores de la biosíntesis de esteroides y observar el efecto de esta hormona sobre la actividad de las enzimas proteolíticas en la pared folicular.

Efeito de diferentes protocolos de superovulação sobre a concentração plasmática de progesterona e de metabólitos lipídicos de vacas Nelore / Effect of different superovulation protocols on plasma progesterone concentration and lypidic metabolites in Nelore cows

Avaliaram-se as concentrações plasmáticas de triglicérides, colesterol, aspartato transaminase (AST) e progesterona (P4) em vacas Nelore não lactantes com elevado escore corporal, superovuladas com diferentes protocolos. Foram utilizados três grupos de animais, G1 (n=11), G2 (n=8) e G3 (n=5), superovulados com 500UI de FSH, 200mg e 180mg de FSH (hormônio folículo estimulante), respectivamente, em doses decrescentes, duas vezes ao dia, durante quatro dias. As amostras de sangue foram coletadas antes da superovulação (A), no terceiro dia da superovulação (B), no momento da inseminação artificial (C) e na coleta dos embriões (D). As concentrações de triglicérides, AST e colesterol foram verificados por espectrofotometria, e a de progesterona (P4) por radioimunoensaio. Não houve alteração (P>0,05) na concentração de triglicérides, AST e colesterol entre as amostras. Não houve efeito (P>0,05) do protocolo de superovulação sobre a concentração de triglicérides, AST e P4 nas diferentes amostras. O G2 apresentou menor concentração de colesterol (P<0,05) nas amostras A e B, possivelmente em razão da grande instabilidade dessa variável.

The purpose of this research was to evaluate the concentration of tryglicerides, cholesterol, aspartate transaminase (AST) and progesterone (P4) in embryo donor Nelore cows superovulated with different protocols. Twenty four donors were randomly distributed in three groups: group 1 (n=11), donors superovulated with 500UI of FSH and group 2 (n=8) and group 3 (n=5) respectively with 200mg and 180mg of FSH, in decreasing doses, twice a day, during four consecutive days. Blood samples were collected before superovulation (A), in the third day of superovulation (B), at the artificial insemination time (C) and at the embryo collection time (D). The concentrations of tryglicerides, aspartate transaminase (AST) and cholesterol were measured by spectrophotometry and progesterone (P4) by radioimmunoassay. There was no alteration (P<0.05) in the concentration of tryglicerides, AST and cholesterol among the samples. There was no effect (P>0.05) of the superovulation protocol on the concentration of tryglicerides, AST and P4 in the samples. In the samples A and B of group 2 the concentration of cholesterol was lower (P<0.05) than in groups 1 and 3, probably due to the instability of the parameter.