Peripheral concentrations of immunoreactive inhibin during pregnancy and parturition in the ewe.
The aim of this study was to measure the peripheral concentrations of immunoreactive inhibin (ir-inhibin) and progesterone (P) during pregnancy and parturition in the ewe and to relate the concentrations of ir-inhibin to P and to the number and sex of the fetuses. P increased across pregnancy with higher levels in ewes with 2 fetuses (n = 5) than in those with 1 fetus (n = 6), and concentrations falling before birth. ir-Inhibin concentrations were relatively stable during the first 40 days of pregnancy for example (Day 20, 34.7 +/- 2.9 pmol L-1; mean +/- s.e.m., n = 11). After Day 40, inhibin fell in all ewes to reach less than or equal to 2.5 pmol L-1 after Day 80 (mean on Day 103, 6.3 +/- 1.2 pmol L-1), and remained low until 2 days before parturition when concentrations rose sharply, peaking at or around the day of birth in all ewes (21.5 +/- 2.1 pmol L-1). Thereafter, ir-inhibin fell and remained low or undetectable for up to 10 days in the six ewes still being sampled. ir-Inhibin concentrations in ewes carrying one (n = 6), two (n = 5) or three fetuses (n = 1) did not differ at any stage of pregnancy examined. The sex of the fetus did not appear to influence the peripheral concentrations of ir-inhibin in the ewe.
Findlay
J K
JK
Prince Henry's Institute of Medical Research, South Melbourne, Vic., Australia.
Doughton
B W
BW
Russell
D L
DL
D000704:Analysis of Variance; D000818:Animals; D005260:Female; D007265:Inhibins / Q000032:analysis; D007743:Labor, Obstetric / Q000502:physiology*; D008098:Litter Size; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011374:Progesterone / Q000032:analysis; D011863:Radioimmunoassay; D012737:Sex Factors; D012756:Sheep
D011374:Progesterone; D007265:Inhibins