Full text not available from this repository.

Abstract

Skeletal muscle microvascular (capillary) blood flow increases in the postprandial state or during insulin infusion due to dilation of precapillary arterioles to augment glucose disposal. This effect occurs independently of changes in large artery function. However, acute hyperglycemia impairs vascular function, causes insulin to vasoconstrict precapillary arterioles, and causes muscle insulin resistance in vivo. We hypothesized that acute hyperglycemia impairs postprandial muscle microvascular perfusion, without disrupting normal large artery hemodynamics, in healthy humans. Fifteen healthy people (5 F/10 M) underwent an oral glucose challenge (OGC, 50 g glucose) and a mixed-meal challenge (MMC) on two separate occasions (randomized, crossover design). At 1 h, both challenges produced a comparable increase (6-fold) in plasma insulin levels. However, the OGC produced a 1.5-fold higher increase in blood glucose compared with the MMC 1 h postingestion. Forearm muscle microvascular blood volume and flow (contrast-enhanced ultrasound) were increased during the MMC (1.3- and 1.9-fold from baseline, respectively, P P < 0.05 for both) despite a similar hyperinsulinemia. Both challenges stimulated brachial artery flow (ultrasound) and heart rate to a similar extent, as well as yielding comparable decreases in diastolic blood pressure and total vascular resistance. Systolic blood pressure and aortic stiffness remained unaltered by either challenge. Independently of large artery hemodynamics, hyperglycemia impairs muscle microvascular blood flow, potentially limiting glucose disposal into skeletal muscle. The OGC reduced microvascular blood flow in muscle peripherally and therefore may underestimate the importance of skeletal muscle in postprandial glucose disposal.

Item Type:	Article
Authors/Creators:	Russell, RD and Hu, D and Greenaway, T and Sharman, JE and Rattigan, S and Richards, SM and Keske, MA
Keywords:	carbohydrate metabolism, insulin action, metabolic physiology, microvascular blood flow, skeletal muscle
Journal or Publication Title:	American Journal of Physiology - Endocrinology and Metabolism
Publisher:	Amer Physiological Soc
ISSN:	0193-1849
DOI / ID Number:	https://doi.org/10.1152/ajpendo.00448.2017
Copyright Information:	Copyright © 2018 the American Physiological Society
Related URLs:	UTAS Profile: Russell, RD Google Scholar: Sharman, JE UTAS Profile: Sharman, JE UTAS Profile: Rattigan, S Google Scholar: Richards, SM UTAS Profile: Richards, SM UTAS Profile: Keske, MA
Item Statistics:	View statistics for this item

Actions (login required)

Item Control Page