Inhibition of corticotropin release during hypothermia: The role of corticotropin-releasing factor, vasopressin, and oxytocin

Daniel M. Gibbs

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

To investigate the mechanism by which ACTH secretion is inhibited during hypothermia, hypophysial portal blood was collected from euthermic and hypothermic rats, and the concentrations of corticotropin-releasing factor (CRF), vasopressin (AVP), and oxytocin (OT) were measured by RIA. Whereas CRF levels in portal plasma were not different in the two groups, AVP and OT levels were significantly lower in hypothermic rats. The concentration of AVP and OT in peripheral plasma was also significantly lower in hypothermic rats compared with euthermic controls. The pituitary responsiveness to CRF during hypothermia was tested in vivo and in vitro. In pentobarbital-anesthetized male rats injected iv with 0.1 or 1.0 nmol CRF, the ACTH response was significantly smaller in hypothermic compared with euthermic animals. However, hemipituitaries superfused at 31 C released the same amount of ACTH in response to 1 nM CRF as hemipituitaries superfused at 37 C (31 C, 541 ± 90 pg; 37 C, 563 ± 29 pg) despite reduced baseline secretion (31 C, 77 ± 10 pg/10 min; 37 C, 114 ± 14 pg/10 min; P < 0.05). The data suggest that the inhibition of ACTH secretion during hypothermia is mediated by decreased hypothalamic secretion of AVP and OT which in turn decreases the pituitary responsiveness to CRF.

Original languageEnglish (US)
Pages (from-to)723-727
Number of pages5
JournalEndocrinology
Volume116
Issue number2
DOIs
StatePublished - Jan 1 1985

ASJC Scopus subject areas

  • Endocrinology

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