Secretory pattern of inhibin A, inhibin B and inhibin pro-alpha C during induced follicular atresia and subsequent follicular development in the golden hamster (Mesocricetus auratus).
The changes in plasma concentrations of inhibins A, B and pro-alpha C were determined in the cyclic golden hamster during follicular atresia induced with antiserum against luteinizing hormone releasing hormone (LHRH-AS) at 1100 h on day 4 (day 1=day of ovulation). Follicular status in the ovary was also studied by determining the number of follicles ovulating in response to human chorionic gonadotrophin (hCG) injection. The time-courses of changes in plasma concentrations of inhibins A, B and pro-alpha C were different from each other during induced follicular atresia and subsequent follicular development. Plasma concentrations of inhibin A decreased to 58.6% of initial values by 24 h after LHRH-AS treatment, and then remained relatively low until at least 60 h later. Plasma concentrations of inhibin B decreased to 64.2% of the initial values by 18 h after LHRH-AS treatment and remained at basal values for 36 h, but increased abruptly to greater than initial values at 42 h after the treatment. Plasma concentrations of inhibin pro-alpha C increased at 6 and 12 h, decreased suddenly to 21.9% of the initial values by 24 h after LHRH-AS treatment, and then gradually increased until 60 h after LHRH-AS. The number of follicles responding to hCG decreased gradually between 0 and 30 h after LHRH-AS, when no ovulations were observed, and then gradually increased until 60 h. The changes in follicular ovulatory responses to hCG correlated with the plasma profile of inhibin A throughout the experiment. These results suggest that inhibin A is mainly secreted by large antral follicles. In contrast, during the subsequent follicular development, the plasma concentration of inhibin B increased earlier than that of inhibin A. These results suggest that inhibin B is secreted by small and large antral follicles. Plasma concentrations of inhibin pro-alpha C were high at a time when plasma concentrations of oestradiol-17 beta had already decreased, indicating that inhibin pro-alpha C is secreted not only from healthy follicles but also from early atretic antral follicles.
Ohshima
K
K
Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183--8509, Japan.
Kishi
H
H
Itoh
M
M
Arai
K Y
KY
Watanabe
G
G
Arai
K
K
Uehara
K
K
Groome
N P
NP
Taya
K
K
D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D006224:Cricetinae; D005260:Female; D005496:Follicular Atresia / Q000502:physiology*; D005498:Follicular Phase / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000276:immunology; D007106:Immune Sera / Q000008:administration & dosage; D007265:Inhibins / Q000097:blood / Q000378:metabolism*; D008647:Mesocricetus; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism*; D011498:Protein Precursors / Q000097:blood / Q000378:metabolism
D006063:Chorionic Gonadotropin; D007106:Immune Sera; D011498:Protein Precursors; C422362:inhibin A; C422364:inhibin B; C095971:inhibin-alpha subunit precursor; D007987:Gonadotropin-Releasing Hormone; D007265:Inhibins