Growth hormone up-regulates gastrin and peptide yy gene
expression.
Gomez, Guillermo, Vidyavathi Udupi, Xiang Qi, Felix Lluis, Srinivasan
Rajaraman, James C. Thompson, George H. Greeley, Jr.
Department of Surgery, The University of Texas Medical Branch,
Galveston, Texas 77555, Department of Surgery, Cirurgia General I
Digestive Hospital Santa Creu I Sant Pau, Barcelona, Spain,
Department of Pathology, The University of Texas Medical Branch,
Galveston, Texas 77555
APStracts 3:0112E, 1996.
The purpose of these studies was to examine the effects of excess
growth hormone (GH) on gastrin and peptide YY (PYY) gene expression.
Transgenic mice with the bovine GH gene linked to a mouse
metallothionein 1 promoter were used as a model of chronic GH excess.
Antral gastrin mRNA and peptide levels were elevated significantly (p
<0.05) in GH transgenic mice when compared to wild type
littermates. Ileal PYY mRNA and ileal and colonic PYY levels were
significantly elevated in GH transgenic mice when compared to wild
type littermates. The elevations in gastrin and PYY gene expression
in GH transgenic mice were independent of food intake. Serum
concentrations of gastrin and PYY were also elevated in GH transgenic
mice. Immunohistochemical analysis showed that the density of PYY
-containing cells in the colon of GH transgenic mice and wild type
littermates did not differ. In addition, the mRNA and protein levels
of chromogranin A (CGA), a marker of endocrine cells, were not
increased in the colon of GH transgenic mice. Together, these data
indicate that GH, IGF-1 or both can up-regulate gastrointestinal
gastrin and PYY gene expression directly.
Received 22 January 1996; accepted in final form 22 May 1996.
APS Manuscript Number E32-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 17 June 96