Bioactive and immunoreactive FSH and immunoreactive inhibin concentrations in the ovine fetus.
The bioactive (B) and immunoreactive (I) pituitary contents/concentrations of FSH, together with the plasma concentrations of B-FSH, I-FSH and I-inhibin were determined in ovine fetuses at days 55, 75, 90 and 135 of gestation (day 145 = term). The pituitary contents and concentrations of B-FSH and I-FSH increased in both sexes with gestational age. The female fetuses had significantly (P < 0.01) higher pituitary contents/concentrations of B-FSH and I-FSH than the male fetuses at days 75 and 135. The pituitary B/I ratios of FSH were not significantly different with age or sex. The plasma concentrations of B-FSH remained relatively constant from days 75 to 135, with no significant differences between sexes or with age. In contrast, the plasma concentrations of I-FSH reached a peak at day 90 and then declined towards term in both sexes. At all gestational ages except day 55, the female fetuses had significantly (P < 0.05) higher plasma concentrations of I-FSH than the males. In both sexes, the plasma B/I ratios of FSH were lowest at day 90 and had increased again by day 135, with the male fetuses having significantly (P < 0.05) higher B/I ratios compared with the female group at days 75 and 135 but not at day 90. At all gestational ages, the plasma concentrations of I-inhibin declined throughout gestation in the female fetuses, whereas in the males they reached a nadir at day 75 and then increased towards term. The concentrations of I-inhibin were significantly (P < 0.01) higher in the male fetuses compared with the females.(ABSTRACT TRUNCATED AT 250 WORDS)
Phillips
D J
DJ
Wallaceville Animal Research Centre, Upper Hutt, New Zealand.
Smith
P R
PR
Heath
D A
DA
Condell
L A
LA
McNatty
K P
KP
D000818:Animals; D005260:Female; D005333:Fetus / Q000378:metabolism*; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism*; D005865:Gestational Age; D007265:Inhibins / Q000097:blood / Q000378:metabolism*; D008297:Male; D012727:Sex Characteristics; D012756:Sheep / Q000196:embryology / Q000378:metabolism*
D007265:Inhibins; D005640:Follicle Stimulating Hormone