Corticotropin-releasing hormone links pituitary adrenocorticotropin gene expression and release during adrenal insufficiency

Corticotropin-releasing hormone (CRH)-deficient (KO) mice provide a unique system to define the role of CRH in regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Despite several manifestations of chronic glucocorticoid insufficiency, basal pituitary proopiomelanocortin (POMC) mRNA, adrenoc...

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Bibliographic Details
Published in:The Journal of clinical investigation 2000-05, Vol.105 (9), p.1269-1277
Main Authors: Muglia, L J, Jacobson, L, Luedke, C, Vogt, S K, Schaefer, M L, Dikkes, P, Fukuda, S, Sakai, Y, Suda, T, Majzoub, J A
Format: Article
Language:English
Subjects:
Adrenal Insufficiency - metabolism
Adrenalectomy
Adrenocorticotropic Hormone - blood
Animals
Corticotropin-Releasing Hormone - pharmacology
Female
Glucocorticoids - pharmacology
Hypothalamo-Hypophyseal System - drug effects
Male
Mice
Mice, Knockout
Pituitary Gland - drug effects
Pituitary-Adrenal System - drug effects
Pro-Opiomelanocortin - biosynthesis
Vasopressins - pharmacology
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Summary:Corticotropin-releasing hormone (CRH)-deficient (KO) mice provide a unique system to define the role of CRH in regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Despite several manifestations of chronic glucocorticoid insufficiency, basal pituitary proopiomelanocortin (POMC) mRNA, adrenocorticotrophic hormone (ACTH) peptide content within the pituitary, and plasma ACTH concentrations are not elevated in CRH KO mice. The normal POMC mRNA content in KO mice is dependent upon residual glucocorticoid secretion, as it increases in both KO and WT mice after adrenalectomy; this increase is reversed by glucocorticoid, but not aldosterone, replacement. However, the normal plasma levels of ACTH in CRH KO mice are not dependent upon residual glucocorticoid secretion, because, after adrenalectomy, these levels do not undergo the normal increase seen in KO mice despite the increase in POMC mRNA content. Administration of CRH restores ACTH secretion to its expected high level in adrenalectomized CRH KO mice. Thus, in adrenal insufficiency, loss of glucocorticoid feedback by itself can increase POMC gene expression in the pituitary; but CRH action is essential for this to result in increased secretion of ACTH. This may explain why, after withdrawal of chronic glucocorticoid treatment, reactivation of CRH secretion is a necessary prerequisite for recovery from suppression of the HPA axis.
ISSN:0021-9738
DOI:10.1172/jci5250