Cortisol feedback on ovine fetal ACTH secretion during the last fifth of gestation.
RJ MacIsaac, JG McDougall, EM Wintour
Reprod Fertil Dev | Published : 1989
This study investigates the development of the feedback relationship between cortisol and ACTH in ovine fetuses at 117-119 (n = 5), 130-134 (n = 4) and 140-143 (n = 6) days of gestation. During the last 2 h of a 24 h cortisol (100 micrograms h-1) or saline (0.19 mL h-1) infusion, the fetal ACTH response to bolus oCRH injection (10 micrograms) was tested after the collection of basal ACTH and cortisol samples. Basal ACTH concentrations in un-infused or saline-infused fetuses were observed to progressively increase after 117-119 days of gestation. In contrast, a prepartum increase in cortisol concentrations could not be detected until after 130-133 days. Cortisol infusion significantly inhibit..View full abstract