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Skeletal Muscle Microvascular Recruitment by Physiological Hyperinsulinemia Precedes Increases in Total Blood Flow

Citation

Vincent, MA and Dawson, D and Clark, ADH and Lindner, JR and Rattigan, S and Clark, MG and Barrett, EJ, Skeletal Muscle Microvascular Recruitment by Physiological Hyperinsulinemia Precedes Increases in Total Blood Flow, Diabetes, 51, (1) pp. 42-48. ISSN 0012-1797 (2002) [Refereed Article]

DOI: doi:10.2337/diabetes.51.1.42

Abstract

Supraphysiological doses of insulin enhance total limb blood flow and recruit capillaries in skeletal muscle. Whether these processes change in response to physiological hyperinsulinemia is uncertain. To examine this, we infused either saline (n = 6) or insulin (euglycemic clamp, 3.0 mU · min -1 · kg -1, n = 9) into anesthetized rats for 120 min. Femoral artery flow was monitored continuously using a Doppler flow probe, and muscle microvascular recruitment was assessed by metabolism of infused 1-methylxanthine (1-MX) and by contrast-enhanced ultrasound (CEU). Insulin infusion raised plasma insulin concentrations by ∼10-fold. Compared with saline, physiological hyperinsulinemia increased femoral artery flow (1.02 ± 0.10 vs. 0.68 ± 0.09 ml/min; P < 0.05), microvascular recruitment (measured by 1-MX metabolism [6.6 ± 0.5 vs. 4.5 ± 0.48 nmol/min; P < 0.05] as well as by CEU [167.0 ± 39.8 vs. 28.2 ± 13.8%; P < 0.01]), and microvascular flow velocity (β, 0.14 ± 0.02 vs. 0.09 ± 0.02 s -1). Subsequently, we studied the time dependency of insulin's vascular action in a second group (n = 5) of animals. Using CEU, microvascular volume was measured at 0, 30, and 90 min of insulin infusion. Insulin augmented microvascular perfusion within 30 min (52.8 ± 14.8%), and this persisted at 90 min (64.6 ± 9.9%). Microvascular recruitment occurred without changes to femoral artery flow or β. We conclude that insulin increases tissue perfusion by recruiting microvascular beds, and at physiological concentrations this precedes increases in total muscle blood flow by 60-90 min.

Item Details

Item Type:Refereed Article
Research Division:Medical and Health Sciences
Research Group:Clinical Sciences
Research Field:Endocrinology
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Diabetes
Author:Clark, ADH (Mr Andrew Clark)
Author:Rattigan, S (Professor Stephen Rattigan)
Author:Clark, MG (Professor Michael Clark)
ID Code:24653
Year Published:2002
Web of Science® Times Cited:121
Deposited By:Biochemistry
Deposited On:2002-08-01
Last Modified:2003-04-14
Downloads:0

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