Insulin-like growth factor-I promotes proliferation and migration of cavernous smooth muscle cells.
To better understand the physiology of cavernous smooth muscle cells (CSMC), particularly their regulation by IGF-I, we isolated CSMC from rats of various ages and grew them as cell cultures. CSMC from very young (1 week of age) and very old (28 months of age) rats secreted the least amounts of IGF-I, and those from 16-week-old rats the most. IGF-I stimulated growth of CSMC at an optimal concentration of 12.5 ng/ml. At this concentration, CSMC from 11-week-old rats showed the highest growth rate and CSMC from 28-month-old rats showed the lowest. The optimal IGF-I concentration for migration of CSMC was 10 ng/ml. At this concentration, CSMC from 4-week-old rats showed the highest migratory rate and CSMC from 28-month-old rats showed the lowest. IGF-I also stimulated VEGF secretion from CSMC at an optimal concentration of 10 ng/ml. At this concentration, CSMC from 16-week-old rats secreted VEGF the most and CSMC from 28-month-old rats secreted the least. The expression levels of IGF-IR paralleled the IGF-I-regulated growth rates of these cells. Expression of IGF-IR was identified in the cavernous smooth muscle and the urethra epithelium of the penis.
Liu
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Knuppe Molecular Urology Laboratory, University of California, San Francisco, California 94143-1695, USA.
Lin
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CS
Spencer
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EM
Lue
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TF
D000375:Aging; D000818:Animals; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects*; D002465:Cell Movement / Q000187:drug effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D016228:Endothelial Growth Factors / Q000378:metabolism; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology*; D008222:Lymphokines / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects; D010413:Penis / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017526:Receptor, IGF Type 1 / Q000378:metabolism; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1