Physiology Commons^™

Cortisol In The Ovine Fetus : Its Regulation And Role In Parturition, Ede Marie Apostolakis

Loma Linda University Electronic Theses, Dissertations & Projects

In fetal sheep, circulating cortisol increase during late gestation to abruptly rise 72 hours preceding birth. Although the surge in cortisol is thought to initiate the endocrine cascade which triggers parturition, it is not known what drives the prepartum rise in fetal cortisol. The first study tested the hypothesis that basal cortisol secretion is regulated by adrenocorticotropin (ACTH) which in turn, is controlled by arginine vasopressin (AVP). The fetus challenged with AVP increased plasma ACTH and cortisol concentrations. Pretreatment with an AVP V₁ receptor antagonist blocked AVP-induced plasma ACTH cortisol but failed to alter basal ACTH or cortisol. To …