Identification of target cells for growth hormone's action in the
arcuate nucleus.
Burton, Kimberly A., Emilia B. Kabigting, Robert A. Steiner, and
Donald K. Clifton.
Departments of Obstetrics and Gynecology (D.K.C., E.B.K., R.A.S.),
Physiology and Biophysics (K.A.B., R.A.S.), Zoology (R.A.S.), and the
Population Center for Research in Reproduction (D.K.C., R.A.S.),
University of Washington, Seattle, WA 98195
APStracts 2:0113E, 1995.
Growth hormone (GH) participates in the regulation of its own
secretion by acting through a short-loop feedback mechanism to
regulate the synthesis and secretion of somatostatin (SS) and growth
hormone-releasing hormone (GHRH). The mechanism of GH's action in
certain peripheral targets involves the induction of cfos. Similarly,
we hypothesized that GH induces the expression of cfos mRNA in SS and
GHRH neurons in the hypothalamus. Using in situ hybridization, we
observed a significant induction of cfos mRNA in the arcuate nucleus
of human GH-treated animals compared with controls. Contrary to our
hypothesis, only 11% of GHRH mRNA-containing and 5% of SS mRNA
-containing neurons colabeled for cfos mRNA. These findings indicate
that GH feedback on the hypothalamus includes the induction of cfos
mRNA primarily in neurons other than GHRH and SS in the arcuate
nucleus and suggest that these unidentified neurons located in the
arcuate nucleus are directly involved in transducing the effects of
GH in the brain.
Received 16 December 1994; accepted in final form 10 May 1995.
APS Manuscript Number E520-4.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 26 May 1995.