AJP - Renal Physiology, Vol 259, Issue 2 251-F257, Copyright © 1990 by American Physiological Society
Renal expression of IGF I in hypersomatotropic states
S. B. Miller, P. Rotwein, J. D. Bortz, P. J. Bechtel, V. A. Hansen, S. A. Rogers and M. R. Hammerman
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
We examined insulin-like growth factor I (IGF I) gene expression in kidney
in two models of hypersomatotropism, rats implanted with GH3 pituitary
tumors, and rats administered exogenous growth hormone (GH). Both GH3
tumor-bearing rats and rats administered GH gained weight more rapidly than
control animals, and had kidneys that were larger than those of controls.
Tumor-bearing rats had increased levels of circulating IGF I. Glomeruli
from tumor-implanted rats were sclerotic. Immunostainable IGF I was
increased in medullary collecting ducts from tumor-bearing and GH-injected
rats compared with kidneys from control animals. Levels of IGF I mRNA in
kidneys of rats implanted with GH3 tumors and GH-injected rats were
elevated compared with levels in kidneys from controls. Our findings
demonstrate enhanced renal IGF I gene expression in hypersomatotropism.
Stimulation of renal IGF I synthesis by GH could be causative of changes in
renal function and renal size that occur in states of GH excess such as
acromegaly.
