Water deprivation upregulates angiotensin ii at1 receptors and
their mrna in rat subfornical organ and anterior pituitary.
Sanvitto, Gilberto L., Olaf J[diaeresis]ohren, Walter H[umlaut]auser,
Juan M. Saavedra.
Section on Pharmacology, Laboratory of Clinical Science, National
Institute of Mental Health, Bethesda, MD 20892, USA
APStracts 4:0078E, 1997.
We studied angiotensin II (Ang II) receptor subtype expression in
selected brain nuclei and pituitary gland after water deprivation by
in vitro receptor autoradiography using [125I]Sar1-Ang II and by in
situ hybridization using 35S-labeled AT1A, AT1B, and AT2 receptor
specific riboprobes. In control rats we found binding to AT1
receptors in the subfornical organ, paraventricular nuclei, median
eminence, and anterior pituitary, AT1A mRNA expression in the
subfornical organ and paraventricular nuclei and AT1B mRNA expression
in the anterior pituitary. No receptor mRNA was found in the median
eminence. AT1 receptors and AT1A receptor mRNA levels were increased
in the subfornical organ, and, in the anterior pituitary, AT1
receptors and AT1B receptor mRNA were increased, only after five days
of water deprivation. No significant changes occurred after one or
three days of water deprivation and no regulation of Ang II receptor
expression was detected in other brain areas. Our results show that
prolonged water deprivation selectively regulates AT1 receptor
expression and AT1A and AT1B receptor mRNA levels in the subfornical
organ and anterior pituitary, respectively, supporting a role for
these receptors during sustained dehydration.
Received 12 September 1996; accepted in final form 20 March 1997.
APS Manuscript Number E459-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 15 April 1997