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Acute vasoconstriction-induced insulin resistance in rat muscle in vivo

Citation

Rattigan, S and Clark, MG and Barrett, EJ, Acute vasoconstriction-induced insulin resistance in rat muscle in vivo, Diabetes, 48, (3) pp. 564-569. ISSN 0012-1797 (1999) [Refereed Article]

DOI: doi:10.2337/diabetes.48.3.564

Abstract

Insulin-mediated changes in blood flow are associated with altered blood flow distribution and increased capillary recruitment in skeletal muscle. Studies in perfused rat hindlimb have shown that muscle metabolism can be regulated by vasoactive agents that control blood flow distribution within the hindlimb. In the present study, the effects of a vasoconstrictive agent that has no direct effect on skeletal muscle metabolism but that alters perfusion distribution in rat hindlimb was investigated in vivo to determine its effects on insulin-mediated vascular action and glucose uptake. We measured the effects of α-methylserotonin (α-met5HT) on mean arterial blood pressure, heart rate, femoral blood flow, hindlimb vascular resistance, and glucose uptake in control and euglycemic insulin-clamped (10 mU · min-1 · kg-1) anesthetized rats. Blood flow distribution within the hindlimb muscles was assessed by measuring the metabolism of 1-methylxanthine (1-MX), an exogenously added substrate for capillary xanthine oxidase. α-Met5HT (20 μg · min-1 · kg-1) infusion alone increased mean arterial blood pressure by 25% and increased hindlimb vascular resistance but caused no change in femoral blood flow. These changes were associated with decreased hindlimb 1-MX metabolism indicating less capillary flow. Insulin infusion caused decreased hindlimb vascular resistance that was associated with increased femoral blood flow and 1-MX metabolism. Treatment with α-met5HT infusion commenced before insulin infusion prevented the increase in femoral blood flow and inhibited the stimulation of 1-MX metabolism. α-Met5HT infusion had no effect on hindlimb glucose uptake but markedly inhibited the insulin stimulation of glucose uptake (P < 0.05) and was associated with decreased glucose infusion rates to maintain euglycemia (P < 0.05). A significant correlation (P < 0.05) was observed between 1-MX metabolism and hindlimb glucose uptake but not between femoral blood flow and glucose uptake. The results indicate that in vivo, certain types of vasoconstriction in muscle such as elicited by 5HT2 agonists, which prevent normal insulin recruitment of capillary flow, cause impaired muscle glucose uptake. Moreover, if vasoconstriction of this kind results from stress-induced increase in sympathetic outflow, then this may provide a clue as to the link between hypertension and insulin resistance that is often observed in humans.

Item Details

Item Type:Refereed Article
Research Division:Medical and Health Sciences
Research Group:Medical Biochemistry and Metabolomics
Research Field:Medical Biochemistry: Carbohydrates
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Diabetes
Author:Rattigan, S (Professor Stephen Rattigan)
Author:Clark, MG (Professor Michael Clark)
ID Code:17086
Year Published:1999
Web of Science® Times Cited:91
Deposited By:Biochemistry
Deposited On:1999-08-01
Last Modified:2011-10-03
Downloads:0

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