Prostaglandins and nitric oxide mediate insulin-induced vasodilation in the human forearm.
OBJECTIVE
To determine the involvement of prostaglandins, nitric oxide, and beta-adrenoceptor activation in insulin-induced vasodilation in the human forearm.


METHODS
Fifteen normal subjects were studied. Insulin was administered into the brachial artery in the presence of saline, the cyclo-oxygenase inhibitor indomethacin (0.65 microgram/kg/min), the inhibitor of nitric oxide synthase NG-mono-methyl-L-arginine (L-NMMA, 30 micrograms/kg/min), or the non-selective beta-adrenoceptor blocker propranolol (0.2 microgram/kg/min). Forearm vascular resistance (FVR) was derived from forearm blood flow and concomitantly measured intra-arterial blood pressure.


RESULTS
Insulin decreased FVR by 32 +/- 5% (P < 0.01). Both indomethacin and L-NMMA inhibited insulin-induced vasodilation, while propranolol had no effect. Single infusion of indomethacin was without effect on vascular tone, while single infusion of L-NMMA increased FVR by 81 +/- 19% (P < 0.01).


CONCLUSIONS
Insulin has vasodilating properties in skeletal muscle vasculature that is mediated by increases in nitric oxide, that subsequently stimulates prostaglandin release. The latter appears to be a novel vascular action of insulin.
van Veen
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Department of Nephrology, University Hospital, Leiden, Netherlands.
Chang
P C
PC
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000328:Adult; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005542:Forearm / Q000098:blood supply; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D011433:Propranolol / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects*; D014664:Vasodilation; D019323:omega-N-Methylarginine / Q000494:pharmacology*
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D016861:Cyclooxygenase Inhibitors; D007328:Insulin; D019323:omega-N-Methylarginine; D011433:Propranolol; D019001:Nitric Oxide Synthase; D007545:Isoproterenol; D007213:Indomethacin