Camp regulation of vasopressin mrna content in hypothalamo
-neurohypophyseal explants.
Sladek, Celia D., Kirsten Y. Fisher, Hanna E. Sidorowicz, and Joanne
R. Mathiasen.
Department of Physiology, Finch University of Health Sciences/ The
Chicago Medical School, North Chicago, IL 60064
APStracts 3:0098R, 1996.
Stimulation of vasopressin (VP) gene expression by cAMP has been
observed in dispersed hypothalamic cultures, in VP expressing cell
lines, and in cells transfected with reporter genes regulated by the
VP gene promoter. However, treatment of hypothalamo-neurohypophyseal
system (HNS) explants with forskolin (25[mu]M), an activator of
adenyl cyclase, and IBMX (500[mu]M), a phosphodiesterase inhibitor,
resulted in a decrease in VP mRNA. Time course analysis revealed that
IBMX and forskolin reduced the VP mRNA content to 50% of control
explants following 8 and 12 hrs in spite of a dramatic stimulation of
VP release. This effect was due to the activation of adenyl cyclase
by forskolin, because neither IBMX alone nor the inactive analog of
forskolin, 1,9-dideoxyforskolin, decreased VP mRNA content. In
contrast, 8-bromo-cAMP and the D1 dopamine receptor agonist, SKF
38393, increased VP mRNA content, but these agents were less potent
in stimulating VP release suggesting a concentration dependency of
the forskolin effect. This was confirmed when forskolin (10[mu]M) was
found to increase VP mRNA content. Thus, receptor-mediated activation
of adenyl cyclase results in an increase in VP mRNA content.
Received 25 January 1995; accepted in final form 27 February
1996.
APS Manuscript Number R60-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 20 March 96