In:
American Journal of Physiology-Endocrinology and Metabolism, American Physiological Society, Vol. 275, No. 6 ( 1998-12-01), p. E1007-E1015
Abstract:
In the rat muscle vascular bed, vasoconstrictors either increase or decrease oxygen consumption (V˙o 2 ). The present study compared the effects of norepinephrine (NE), angiotensin II (ANG II), and 5-hydroxytryptamine (5-HT) on vasoconstriction-associated metabolism in the constant-flow perfused hindlimb of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) in the absence of insulin. Basal perfusion pressure,V˙o 2 , glucose uptake, and lactate production were increased by 21.4, 11.9, 46.4, and 44.9% ( P 〈 0.05 for all), respectively, in SHR, which also had higher blood pressure and metabolic rate ( P 〈 0.05) in vivo. Dose-response curves for NE-induced perfusion pressure,V˙o 2 , and lactate production in SHR were shifted to the left compared with WKY. Associated with the increased perfusion pressure, NE-inducedV˙o 2 and glucose uptake were both decreased ( P 〈 0.01), particularly at high concentrations. These differences were unaffected by 10 μM propranolol but were all diminished by further addition of prazosin (2.5 nM). ANG II stimulatedV˙o 2 , glucose uptake, and lactate production in both strains, but the increased lactate production was smaller in SHR ( P 〈 0.05) with a proportional decrease ( P 〈 0.05) in glucose uptake. Conversely, 5-HT decreasedV˙o 2 in both strains ( P 〈 0.01), and this effect was greater in SHR ( P 〈 0.01). These data suggest that SHR muscle thermogenesis and glucose uptake are impaired during vasoconstriction, especially in response to NE.
Type of Medium:
Online Resource
ISSN:
0193-1849
,
1522-1555
DOI:
10.1152/ajpendo.1998.275.6.E1007
Language:
English
Publisher:
American Physiological Society
Publication Date:
1998
detail.hit.zdb_id:
1477331-4
SSG:
12
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