Effects of hypophysectomy on vascular insulin-like growth factor-I gene expression after balloon denudation in rats.
Insulin-like growth factor-I (IGF-I) is a widely distributed mediator of the growth promoting effects of growth hormone (GH). We sought to determine whether the relationship between GH and IGF-I extends to the vascular system, where IGF-I is proposed to participate in the process of neointimal proliferation after balloon denudation. We show that in hypophysectomized rats basal aortic IGF-I mRNA is one-tenth that of normal rats and is increased after balloon denudation. The induction peaks at 7 days after balloon denudation at about 10-fold control levels, similar to normal rats. Treatment with GH restores basal IGF-I mRNA content to approximately half that of normal rats, without further increase in the relative magnitude of induction after balloon denudation. This local induction of IGF-I gene expression in the vessel wall following injury might explain why neointimal proliferation is not inhibited more profoundly after hypophysectomy.
Khorsandi
M
M
Division of Cardiology, Cedars-Sinai Medical Center, Los Angeles, CA 90048-1896.
Fagin
J A
JA
Fishbein
M C
MC
Forrester
J S
JS
Cercek
B
B
D000818:Animals; D001011:Aorta / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D002455:Cell Division; D004730:Endothelium, Vascular / Q000293:injuries / Q000378:metabolism / Q000473:pathology*; D015870:Gene Expression; D013006:Growth Hormone / Q000502:physiology; D007016:Hypophysectomy; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone