Comparison of age-related anti Müllerian hormone, inhibin-b levels and follicle reserve in rat ovarium / Comparación de la hormona anti-mülleriana relacionada con la edad, los niveles de inhibina-b y la reserva folicular en el ovario de rata

SUMMARY: Anti-Müllerian hormone (AMH) and Inhibin B (INHB) in the glycoprotein structure are members of the transforming growth factor β family and expressed by granulosa cells from puberty. AMH is a factor that increases the life span of small developing follicles. For this reason, it is widely used to determine the ovarian reserve and age. Inhibin-B secreted from granulosa cells plays a role in regulation of the Follicle Stimulating Factor (FSH) and determination of the follicle diameter. There are few studies on the effect of these two age-related hormones on ovarian histology in rats. In this study, AMH and INHB expression in ovarian tissues of female rats of different age groups, their relationship with ovarian structure and folliculogenesis were examined histologically and biochemically. Wistar Albino rats were used in the study and a total of 3 groups were formed. The ovaries of rats in the pre-oestrous period were collected, and follicle count was performed on tissue sections in batches. Expression of AMH in the follicles was identified immunohistochemically. In serum, AMH and INHB levels were assessed by ELISA method and their significance was evaluated statistically. Results from light microscopic examination determined that AMH was expressed from the granulosa cells of developing follicles. INHB expression during the prepubertal period and AMH had a protective effect on the ovarian reserve and the number of developing follicles, respectively.

RESUMEN: La hormona antimülleriana (AMH) y la inhibina B (INHB) en la estructura de la glicoproteína son miembros de la familia del factor de crecimiento transformante β y se expresan en las células de la granulosa desde la pubertad. La AMH es un factor que aumenta la vida útil de los pequeños folículos en desarrollo. Por este motivo, se utiliza frecuentemente para determinar la reserva ovárica y la edad. La inhibina B secretada por las células de la granulosa tiene un rol en la regulación del factor estimulante de (FSH) y en la determinación del diámetro del folículo. Hay pocos estudios sobre el efecto de estas dos hormonas relacionadas con la edad en la histología ovárica en ratas. Se examinaron histológica y bioquímicamente la expresión de AMH e INHB en tejidos ováricos de ratas hembras de diferentes grupos de edad, su relación con la estructura ovárica y la foliculogénesis. Se utilizaron ratas Wistar Albino en el estudio y se formaron 3 grupos. En los ovarios de ratas en el período preestro se realizó el recuento de folículos en secciones de tejido. La expresión de AMH en los folículos se identificó inmunohistoquímicamente. En suero, los niveles de AMH e INHB se evaluaron mediante el método ELISA y su importancia se evaluó estadísticamente. Los resultados del examen con microscopio óptico determinaron que la AMH se expresaba a partir de las células de la granulosa de los folículos en desarrollo. La expresión de INHB durante el período prepuberal y AMH tuvo un efecto protector sobre la reserva ovárica y el número de folículos en desarrollo, respectivamente.

Follicular fluid immunoreactive-inhibin concentrations in relation to follicular diameter and estradiol-17 beta, progesterone and testosterone concentrations in individual ovarian follicles in buffalo, Bubalus bubalis.

The objective of this study was to measure the concentrations of immunoreactive inhibin (ir-inhibin) in follicular fluid from individual ovarian follicles and relate them to follicular diameter and follicular fluid concentrations of estradiol-17 beta, progesterone and testosterone in buffalo. Follicular size was measured with an ultrasound machine and follicles were categorized as small (4 to 5 mm diam.), medium (6 to 9 mm diam.) and large (10 mm and above in diam.). Ir-inhibin concentrations varied markedly between and within follicles of same size category. Follicular fluid ir-inhibin concentrations (microgram/ml) were positively related to follicular diameter (R = 0.32, n = 262, P < 0.001) and were significantly higher (P < 0.05) in large (8.32 +/- 0.56) in comparison to medium (7.02 +/- 0.31) follicles which, in turn had inhibin concentrations significantly higher (P < 0.001) than those in small follicles (5.13 +/- 0.48). Ir-inhibin and estradiol-17 beta concentrations were positively related in medium (R = 0.38, n = 128, P < 0.001) and large (R = 0.64, n = 35, P < 0.001) but not in small follicles. There was a negative relationship between ir-inhibin and progesterone concentrations in large follicles (R = 0.46, n = 33, P < 0.01), with no relationship between the two hormones in small and medium follicles. Ir-inhibin was positively related to molar ratios of estradiol-17 beta to progesterone in medium (R = 0.30, n = 124, P < 0.01) and large (R = 0.49, n = 24, P < 0.01) but not in small follicles. There was no relationship between ir-inhibin and testosterone concentrations in follicles of all size categories. The results of the present study suggest that follicular inhibin production is related to follicular size as well as intrafollicular estradiol-17 beta and progesterone concentrations.

Endocrinologia do ovário no climatério perimenopáusico / The ovarian endocrinology in the perimenopausal period

O climatério, período de transiçäo entre o menacme e a senectude, compreende uma série de fenômenos clínicos, biológicos e endocrinológicos, que se iniciam muito antes da instalaçäo da menopausa e prosseguem por anos após a mesma. A endocrinologia de transiçäo menopáusica, compreendida nesse período, é o objetivo do presente trabalho de revisäo da literatura. Observa-se, inicialmente, diminuiçäo na secreçäo de Inibina, um polipeptídeo produzido pelas células da granulosa, responsável por modulaçäo da secreçäo de FSH. Há aumento do FSH, seguido de aumento do LH e diminuiçäo da esteroidogênese ovariana, resultando em hipoestrogenismo e diminuiçäo dos níveis de progesterona, o que concorre para a série de alteraçöes que caracterizam esse período.

Inhibin in individual buffalo ovarian follicles in relation to size.

A sensitive and specific radioimmunoassay was validated and applied for measurement of inhibin in follicular fluid (bFF) obtained from individual buffalo ovarian follicles. Follicular size was measured with an ultrasound machine and follicles were categorized as small, medium and large. Presence of inhibin was detected in all the antral follicles above 3 mm diameter. Inhibin concentration showed a positive relationship (R = 0.27, P < 0.01) with follicular diameter and was significantly higher (P < 0.05) in bFF from medium and large follicles (8.44 +/- 0.54 and 7.70 +/- 0.45 micrograms/ml, respectively) in comparison to that from small follicles (5.74 +/- 0.80 micrograms/ml). Total inhibin content was highly correlated (R = 0.92, P < 0.001) with follicular diameter and the inhibin content was higher (P < 0.001) in large > medium > small follicles.