Secretion of inhibin A, inhibin B and inhibin pro-alphaC during the oestrous cycle of the golden hamster (Mesocricetus auratus).
Plasma concentrations of inhibin pro-alphaC, inhibin A and inhibin B were determined by enzyme-linked immunosorbent assay at 6 h intervals throughout the 4-day oestrous cycle of the golden hamster. Plasma concentrations of follicle-stimulating hormone (FSH) and oestradiol-17beta were also measured by radioimmunoassay during the oestrous cycle. Plasma concentrations of inhibin A increased from the early morning of day 1 (day 1=day of ovulation) and reached plateau levels at 0500 h on day 2. An abrupt increase in plasma concentrations of inhibin A was found at 1700 h on day 4, when the preovulatory FSH surge was observed. An increase in plasma concentrations of inhibin B occurred on day 1 and reached plateau levels at 1700 h on day 1. The levels remained elevated until 0500 h on day 4 and declined gradually by 2300 h on day 4. Plasma concentrations of inhibin pro-alphaC gradually increased with some fluctuation from day 1 to 1700 h on day 4 and then declined. Significant negative relationships were noted between plasma FSH and both dimeric forms of inhibin from day 1 to day 3. Significant positive relationships were found between plasma oestradiol-17beta and inhibin A or inhibin pro-alphaC throughout the oestrous cycle. In contrast, no significant relationship was found between plasma oestradiol-17beta and inhibin B. These findings suggest that both dimeric forms of inhibin play a role in the regulation of FSH secretion during follicular development. These findings also suggest that inhibin pro-alphaC could be secreted primarily by large follicles, and early atretic follicles could also be responsible for inhibin pro-alphaC secretion. On the other hand, the secretory pattern of dimeric inhibins might shift from inhibin B to inhibin A with follicular development.
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
Watanabe
G
G
Arai
K
K
Uehara
K
K
Groome
N P
NP
Taya
K
K
D000818:Animals; D006224:Cricetinae; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000097:blood; D004971:Estrus / Q000097:blood*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D007265:Inhibins / Q000097:blood; D008647:Mesocricetus / Q000502:physiology*; D010455:Peptides / Q000097:blood*; D029584:Prostatic Secretory Proteins; D020033:Protein Isoforms / Q000097:blood; D011498:Protein Precursors / Q000097:blood
D010455:Peptides; D029584:Prostatic Secretory Proteins; D020033:Protein Isoforms; D011498:Protein Precursors; C043076:beta-microseminoprotein; C095971:inhibin-alpha subunit precursor; D004958:Estradiol; D007265:Inhibins; D005640:Follicle Stimulating Hormone