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.
Miller
S B
SB
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
Rotwein
P
P
Bortz
J D
JD
Bechtel
P J
PJ
Hansen
V A
VA
Rogers
S A
SA
Hammerman
M R
MR
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