Inhibin and activin secretion during murine preantral follicle culture and following HCG stimulation.
BACKGROUND
Isolation and culture to antral stage of mouse preantral follicles provides an ideal system for investigating the endocrinology of follicular development to maturity.


METHODS
The release of inhibin A, inhibin B, pro-alphaC and activin A was measured at specific time-points throughout an in-vitro culture period of 8 days. At the end of culture, follicles were induced to ovulate in vitro by the addition of HCG and the resulting hormone secretion studied both at 20 h and at 6 h intervals.


RESULTS
During the preovulatory culture period, the concentrations of inhibin A, B, pro-alphaC and activin A increased significantly. Compared with control, there was a significant decline at 24 h in the concentrations of inhibin A [P < 0.001; 216 +/- 47 versus 823 +/- 110 arbitrary mouse units (amu)/ml], inhibin B (P < 0.01; 131 +/- 23 versus 361 +/- 45 amu/ml) and pro-alphaC (P < 0.001; 14 +/- 5 versus 1198 +/- 212 pg/ml). In contrast, there was a significant increase in the concentration of activin A (P < 0.001; 1.32 +/- 0.04 versus 0.34 +/- 0.03 ng/ml).


CONCLUSIONS
These data provide clear evidence of a profound change in the relative secretion rates of inhibin and activin relative to ovulation and suggest that the principal role of activin A may be at time of ovulation rather than during follicular development.
Newton
H
H
Department of Reproductive Medicine, Westmead Hospital, Westmead, Sydney, NSW 2145, Australia,
Wang
Y
Y
Groome
N P
NP
Illingworth
P
P
D028341:Activins / Q000378:metabolism*; D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D005260:Female; D028322:Inhibin-beta Subunits / Q000378:metabolism*; D007265:Inhibins / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D009924:Organ Culture Techniques; D006080:Ovarian Follicle / Q000187:drug effects* / Q000502:physiology*; D010060:Ovulation / Q000502:physiology*; D010062:Ovulation Induction; D011498:Protein Precursors / Q000378:metabolism
D006063:Chorionic Gonadotropin; D011498:Protein Precursors; C422405:activin A; C422362:inhibin A; C422364:inhibin B; C095971:inhibin-alpha subunit precursor; D028341:Activins; D007265:Inhibins; D028322:Inhibin-beta Subunits