Bioactive and immunoreactive FSH and immunoreactive inhibin concentrations in the ovine fetus

Abstract

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)

Plasma FSH, LH and immunoreactive inhibin concentrations in FecBB/FecBB and FecB+/FecB+ Booroola ewes and rams from birth to 12 months of age

“…The Booroola (FecB ) gene is manifested in ewes as an increase in ovulation rate (Davis et al, 1982 Montgomery Phillips et al, 1992;Braw-Tal et al, 1993;Smith et al, 1993Smith et al, , 1994. In ram lambs, the effects of the FecBB gene on plasma hormone concentrations are equivocal (Seek el al, 1988;Montgomery et al, 1989;Purvis el al, 1991) and, to our (Bindon, 1984;McNatty et al, 1991aMcNatty et al, , 1992Montgomery el al, 1992 (McNatty et al, 1987a(McNatty et al, , 1989(McNatty et al, , 1993a.…”

Effects of the Booroola gene (FecB) on body weight, ovarian development and hormone concentrations during fetal life

“…Some time later, but before day 75, atresia of a pro¬ portion of the germ cells is evident with follicular formation and growth beginning at, or after, about day 75 and about day 90, respectively (Mauleon, 1969). With regard to gonadal hor¬ mones, immunoreactive (i)-inhibin has been detected in the plasma of sheep fetuses (of both sexes) from day 55 of gestation (Smith el al, 1991;Phillips et al, 1992) as well as in the testis at day 50 (Wongprasartsuk et al, 1991). In female sheep fetuses, the concentrations of plasma i-inhibin were highest at day 55 (e.g.…”

“…in ewes the mean concentrations of plasma i-inhibin are about 12 iu ml-1 . At (Caldani and Batailler, 1991) and i-hypothalamic GnRH and pituitary i-FSH and i-LH have been detected at about days [55][56][57][58][59][60] (Gluckman, 1981;Smith et al, 1991;Phillips et al, 1992). From days 75 to 135 of ges¬ tation, the pituitary contents and concentrations of bioactive (b-) and i-FSH increase with increasing age but no change in b:i ratios have been noted (Phillips et al, 1992).…”

“…At (Caldani and Batailler, 1991) and i-hypothalamic GnRH and pituitary i-FSH and i-LH have been detected at about days [55][56][57][58][59][60] (Gluckman, 1981;Smith et al, 1991;Phillips et al, 1992). From days 75 to 135 of ges¬ tation, the pituitary contents and concentrations of bioactive (b-) and i-FSH increase with increasing age but no change in b:i ratios have been noted (Phillips et al, 1992). By contrast, the plasma concentrations of b-FSH remained essentially unchanged from days 75 to 135, whereas those for i-FSH reached a peak at day 90 and then declined towards term indicating that changes were occurring in the plasma b:i ratios for this hormone.…”

“…i-and b-FSH, i-LH, iinhibin and oestradiol) in the female at specific times during fetal life, namely days 40,55,75,90,95 (Gundersen and Jensen, 1987; see also Michel and Cruz-Orive, 1988 (Gunderson, 1986 Padmanabhan et al (1987): the only modification was the use of a 0.5 ml substrate incubation volume instead of 1 ml. The validation of this assay for fetal sheep plasma has been reported by Phillips et al (1992). Concentrations of b-FSH were measured using the production of oestradiol in vitro from Sertoli cells isolated from the immature male rats.…”