Renal expression of IGF I in hypersomatotropic states.
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.
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
S B
SB
Miller
P
P
Rotwein
J D
JD
Bortz
P J
PJ
Bechtel
V A
VA
Hansen
S A
SA
Rogers
M R
MR
Hammerman
D000818:Animals; D005260:Female; D013006:Growth Hormone / Q000378:metabolism / Q000494:pharmacology*; D007150:Immunohistochemistry / Q000379:methods; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D007668:Kidney / Q000473:pathology / Q000502:physiology* / Q000503:physiopathology; D010911:Pituitary Neoplasms / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011920:Rats, Inbred WF; D013002:Somatomedins / Q000235:genetics*; D013194:Staining and Labeling
D012333:RNA, Messenger; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone