Long-term hypoxia enhances ACTH response to arginine vasopressin but not corticotropin-releasing hormone in the near-term ovine fetus.

ABSTRACT: This study tested the hypothesis that long-term hypoxia (LTH) results in enhanced fetal corticotrope sensitivity to the ACTH secretagogues, corticotropin-releasing hormone (CRH), and AVP. Ewes were maintained at high altitude (3,820 m) from 40 to 130-131 days of gestation. Upon return to the laboratory, hypoxia was maintained by maternal nitrogen infusion. Vascular catheters were placed in both LTH (n = 4) and normoxic controls (n = 4). Each fetus received a 15-min infusion of either saline, 100 ng/kg of ovine CRH, or 20 ng/kg of AVP/min over 3 consecutive days in a randomized order. Fetal blood samples were collected at 0, 15, 30, 60, and 90 min after the start of infusion and analyzed for ACTH(1-39), ACTH precursors, and cortisol. Anterior pituitaries were collected from additional nonin

SUBMITTER: Ducsay CA 

PROVIDER: S-EPMC2739789 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature