Inhibin secretion by individual porcine follicles perifused in vitro.
To examine the relative contribution of dominant and nondominant follicles to ovarian inhibin secretion, individual porcine follicles (n = 69, diameter 4 to 9 mm) were perifused in vitro for 12 hours and then histologically examined via light microscopy. Follicle-stimulating hormone (FSH, 1 microgram/mL) was added during the second half of the perifusion period. Levels of 32 kD inhibin, estradiol (E2), and progesterone (P) in perifusion media were determined by radioimmunoassay. Viable and atretic follicles of medium size (4 to 7 mm) secreted negligible amounts of inhibin. Significant levels of inhibin (2 to 5 ng/mL) were only found in media from large viable follicles. In contrast to media concentrations of E2 and P, inhibin levels did not rise during FSH stimulation. Levels of inhibin correlated with those of P (P less than 0.01) but not with those of E2. In conclusion, mature dominant follicles may be the principal source of peripheral inhibin during the follicular phase.
Westhof
G
G
University of Hamburg School of Medicine, West Germany.
Westhof
K F
KF
Hasegawa
Y
Y
Miyamoto
K
K
diZerega
G S
GS
D000818:Animals; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D005496:Follicular Atresia / Q000502:physiology; D007265:Inhibins / Q000378:metabolism*; D006080:Ovarian Follicle / Q000033:anatomy & histology / Q000378:metabolism*; D010477:Perfusion / Q000379:methods; D011863:Radioimmunoassay; D013552:Swine
D004958:Estradiol; D007265:Inhibins; D005640:Follicle Stimulating Hormone