Role of nitric oxide in insulin-induced hypothermia in rats.
Hypothermia is a well-known phenomenon which accompanies hypoglycemia in mammals. The present study was designed to test the hypothesis that nitric oxide (NO) plays a role in insulin-induced hypothermia. The body temperature (Tb) of awake, unrestrained rats was measured before and after systemic infusion of insulin (2U x kg(-1) x h(-1)), and intracerebroventricular administration of NG-nitro-(L)-arginine methyl ester (L-NAME, a nonselective NO synthase inhibitor, 200 microg/1 microl). We observed a significant reduction in body temperature after insulin infusion. L-NAME alone caused no significant change in body temperature. When the two treatments were combined, no change in Tb was observed. The data indicate that NO plays a key role in insulin-induced hypothermia.
Departamento de Morfologia Estomatologia e Fisiologia, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
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D000818:Animals; D001786:Blood Glucose; D001831:Body Temperature / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007035:Hypothermia / Q000139:chemically induced / Q000378:metabolism*; D007276:Injections, Intraventricular; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose; D004791:Enzyme Inhibitors; D007004:Hypoglycemic Agents; D007328:Insulin; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester