INSULIN-LIKE-GROWTH-FACTOR-1 INCREASES VASCULAR SMOOTH-MUSCLE NITRIC-OXIDE PRODUCTION

Insulin like growth factor 1 (IGF-1) vasodilates, increases blood flow and lowers blood pressure; nitric oxide (NO) has been suggested to me diate some of these effects. We studied the role of IGF-1 in the regul ation of NO production in vascular smooth muscle cells (VSMC). IGF-1 i nduced a concentration and time-dependent increase in NO release from endothelium-denuded aortic rings. Pre-incubation with cycloheximide or aminoguanidine blocked IGF-l-stimulated NO release. In addition, a si x-fold increase in NO production by VSMC was seen upon incubation with IGF-1. These results suggest that IGF-1 induces NO release in VSMC th rough a process that involves new protein synthesis and the inducible isoform of nitric oxide synthase.