The effect of cyclosporine administration on growth hormone release and serum concentrations of insulin-like growth factor-I in male rats.
The aim of this work was to study the effect of cyclosporine on the somatotropic axis. Accordingly, growth hormone (GH) secretion, circulating insulin-like growth factor I (IGF-I) and IGF binding proteins (IGFBPs) in response to cyclosporin A (CsA) treatment were examined in adult male Wistar rats. Cyclosporine administration (5, 10 or 20 mg/Kg daily) over 8 days did not modify the body weight, but it did decrease serum concentration of corticosterone and increased serum IGF-I and GH levels. Rats treated with 5 and 10 mg/Kg of cyclosporine had similar levels of serum IGFBPs to control rats, but there was an increase in circulating IGFBP-3 and IGFPB-1,2 in the group treated with 20 mg/Kg of CsA. The increase in circulating GH correlates with a decrease in pituitary GH content in CsA treated rats, with no modification in hypothalamic somatostatin content, suggesting an increase in pituitary GH release. In order to test this hypothesis, anterior pituitary cell cultures were exposed to different CsA concentrations during a 4 h incubation period. Cyclosporine increased GH secretion in cultured pituitary cells (p<0.05). These data suggest that cyclosporine increases circulating IGF-I and GH by stimulating pituitary GH release.
López-Calderón
A
A
Dpt Fisiología, Fac Medicina, Univ Complutense, Madrid, Spain. ALC@eucmax.sim.es
Soto
L
L
Villanúa
M A
MA
Vidarte
L
L
Martín
A I
AI
D000818:Animals; D002478:Cells, Cultured; D003345:Corticosterone / Q000097:blood; D016572:Cyclosporine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D013006:Growth Hormone / Q000378:metabolism*; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D007166:Immunosuppressive Agents; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I; D016572:Cyclosporine; D013006:Growth Hormone; D003345:Corticosterone