Translator Disclaimer
1 August 2002 Effects of a Gonadotropin-Releasing Hormone Agonist on Rat Ovarian Follicle Apoptosis: Regulation by Epidermal Growth Factor and the Expression of Bcl-2-Related Genes
Author Affiliations +
Abstract

The purpose of the present study was to evaluate the in vivo effect of the GnRH analogue leuprolide acetate (LA) on follicular development and apoptosis-related mechanisms in preovulatory ovarian follicles (POF) obtained from prepubertal eCG-treated rats. Serum progesterone and estradiol levels were measured, and a significant decrease in circulating estradiol levels was observed in the LA group, whereas serum progesterone levels remained unchanged. Ovarian histology revealed an inhibitory effect of LA treatment on the follicular development induced by eCG. After 48 h of LA treatment, the numbers of atretic and preantral follicles were increased as compared with controls, whereas the number of antral follicles had decreased. Cells undergoing DNA fragmentation were quantified by performing in situ 3′ end labeling of DNA with digoxygenin-dUTP on ovarian sections. LA treatment caused an increase in the percentage of apoptotic cells in preantral and antral follicles. DNA isolated from these POF incubated 24 h in serum-free medium exhibited the typical apoptotic DNA degradation pattern. Treatment of follicles with epidermal growth factor (EGF) suppressed the spontaneous onset of DNA fragmentation, and a similar effect was observed in LA follicles. POF obtained from LA-treated rats showed no changes in Bcl-2 or Bax protein levels. However, a reduction in the Bcl-xL:Bcl-xS ratio was observed, with a greater decrease in Bcl-xL compared with Bcl-xS during the incubation, suggesting a lower stability of the Bcl-xL isoform in the LA group. These results indicate that in vivo GnRH agonist treatment produces an increase in the apoptosis process in POF from eCG-treated rats, and this effect is reversed in vitro by EGF. This GnRH analogue also reduced the stability of the Bcl-xL protein, thus interfering with follicular development by an as yet unknown mechanism.

Fernanda Parborell, Adali Pecci, Olga Gonzalez, Alejandra Vitale, and Marta Tesone "Effects of a Gonadotropin-Releasing Hormone Agonist on Rat Ovarian Follicle Apoptosis: Regulation by Epidermal Growth Factor and the Expression of Bcl-2-Related Genes," Biology of Reproduction 67(2), 481-486, (1 August 2002). https://doi.org/10.1095/biolreprod67.2.481
Received: 21 September 2001; Accepted: 1 February 2002; Published: 1 August 2002
JOURNAL ARTICLE
6 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top