Nitric oxide synthesis inhibitor prevents vasodilation by insulin-like growth factor I

The effect of insulin-like growth factor I (IGF-I) on renal blood flow was measured in the anaesthetized rat using an electromagnetic flow probe. Renal vasodilation induced by IGF-I (50 micrograms/kg) was completely inhibited by NG-nitro-l-arginine methyl ester (50 mg/kg), an inhibitor of nitric oxide biosynthesis, but only partially reduced by indomethacin (10 mg/kg). The involvement of nitric oxide synthesis in the renal actions of IGF-I is proposed.