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Regulation of follicular luteinization by a gonadotropin‐releasing hormone agonist: Relationship between steroidogenesis and apoptosis
Author(s) -
Andreu Claudia,
Parborell Fernanda,
Vanzulli Silvia,
Chemes Hector,
Tesone Marta
Publication year - 1998
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/(sici)1098-2795(199811)51:3<287::aid-mrd8>3.0.co;2-l
Subject(s) - medicine , endocrinology , biology , antral follicle , equine chorionic gonadotropin , human chorionic gonadotropin , gonadotropin , follicular phase , cholesterol side chain cleavage enzyme , luteal phase , estrous cycle , corpus luteum , ovarian follicle , ovary , collagenase , hormone , ovulation , enzyme , metabolism , cytochrome p450 , biochemistry
The purpose of this study was to evaluate the effects of GnRH‐analog (Leuprolide acetate, LA) administration on follicular luteinization in equine chorionic gonadotropin plus human chorionic gonadotropin (eCG + hCG)‐superovulated prepubertal treated rats. Results indicate that LA treatment decreases circulating levels of progesterone (P) and P accumulation in collagenase‐dispersed ovarian cell cultures, though estradiol(E 2 ) production is increased. These data suggest that cells from the LA group may be less luteinized following gonadotropin treatment. Studies performed on histological ovarian sections after different times of eCG administration showed that LA injections produce lower amounts of corpora lutea and antral follicles, and a greater number of atretic and preantral follicles. The basal and LH‐stimulated P and progestagen accumulations are decreased in incubations of corpora lutea isolated from the LA group. In addition, the mitochondrial cholesterol side‐chain cleavage (P450 SCC ) levels in corpora lutea from LA‐treated rats are reduced, indicating that the decrease in P production observed is due in part to an alteration in the steroidogenic luteal capability. Immunocytochemical localization of nuclei exhibiting DNA fragmentation by the technique of terminal deoxynucleotidyl transferase end‐labeling showed that LA treatment causes an increase in the number of apoptotic cells in preantral and antral follicles at all times studied (1, 2, 4, or 7 days of LA administration). A similar effect, though less pronounced, was observed in corpora lutea. It is concluded that LA treatment produces a failure in the steroidogenic luteal capability and an increase of apoptotic mechanisms in the ovary, producing as a consequence an interference in the follicular recruitment, growth, and luteinization induced by gonadotropins. Mol. Reprod. Dev. 51:287–294, 1998. © 1998 Wiley‐Liss, Inc.