Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.

Glucose utilization was studied in isolated fat cells prepared from rat adipose tissue which had been cultured for 18 hr in TC 199 medium. When 1% bovine serum albumin (BSA) was in the culture medium, basal rates of (14)CO(2) and [(14)C]triglyceride production from [1-(14)C]glucose were markedly dep...

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Main Author: R S Bernstein
Format: Article
Language:English
Published: Elsevier 1979-09-01
Series:Journal of Lipid Research
Online Access:http://www.sciencedirect.com/science/article/pii/S0022227520400148
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spelling doaj-b2b4ebc5e3e041ae8833488f714de1dc2021-04-24T05:52:40ZengElsevierJournal of Lipid Research0022-22751979-09-01207848856Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.R S BernsteinGlucose utilization was studied in isolated fat cells prepared from rat adipose tissue which had been cultured for 18 hr in TC 199 medium. When 1% bovine serum albumin (BSA) was in the culture medium, basal rates of (14)CO(2) and [(14)C]triglyceride production from [1-(14)C]glucose were markedly depressed and there was no effect of insulin. With 4% BSA, basal (14)CO(2) production was the same as in cells prepared from fresh tissue and basal triglyceride production was greatly increased. Insulin effect on these cells was minimal. One-minute uptake of [(14)C]2-deoxyglucose was stimulated by 800-1000% in fresh cells and 300-500% in cells cultured with either 1% or 4% BSA. Oxidation of [U-(14)C]glucose showed a much smaller impairment in cultured cells than for [1-(14)C]glucose, suggesting that the pentose phosphate shunt was more severely impaired than glycolysis. Glyceride-glycerol production was increased in cultured cells relative to preculture (fresh) cells. There was no effect of insulin in the culture medium in any of these systems. Rates of free fatty acid and glycerol release were markedly increased in cultured cells, especially when insulin was present in the culture medium. The acute antilipolytic effect of insulin was retained, so that insulin in the test incubation decreased lipolysis by 40-80%. Nevertheless, cell-associated fatty acids were increased in cultured cells and FFA/albumin ratios in the medium often reached potentially toxic levels. The reduction in pentose phosphate shunt activity, lipogenesis, and insulin effect resembles other models of insulin insensitivity. The impaired metabolism is probably due to an intracellular defect. A possible toxic role of either intracellular or extracellular fatty acids cannot be excluded. This system should be a useful model in which to study the cellular mechanisms of insulin insensitivity in adipocytes.-Bernstein, R. S. Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.http://www.sciencedirect.com/science/article/pii/S0022227520400148
collection DOAJ
language English
format Article
sources DOAJ
author R S Bernstein
spellingShingle R S Bernstein
Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.
Journal of Lipid Research
author_facet R S Bernstein
author_sort R S Bernstein
title Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.
title_short Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.
title_full Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.
title_fullStr Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.
title_full_unstemmed Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.
title_sort insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.
publisher Elsevier
series Journal of Lipid Research
issn 0022-2275
publishDate 1979-09-01
description Glucose utilization was studied in isolated fat cells prepared from rat adipose tissue which had been cultured for 18 hr in TC 199 medium. When 1% bovine serum albumin (BSA) was in the culture medium, basal rates of (14)CO(2) and [(14)C]triglyceride production from [1-(14)C]glucose were markedly depressed and there was no effect of insulin. With 4% BSA, basal (14)CO(2) production was the same as in cells prepared from fresh tissue and basal triglyceride production was greatly increased. Insulin effect on these cells was minimal. One-minute uptake of [(14)C]2-deoxyglucose was stimulated by 800-1000% in fresh cells and 300-500% in cells cultured with either 1% or 4% BSA. Oxidation of [U-(14)C]glucose showed a much smaller impairment in cultured cells than for [1-(14)C]glucose, suggesting that the pentose phosphate shunt was more severely impaired than glycolysis. Glyceride-glycerol production was increased in cultured cells relative to preculture (fresh) cells. There was no effect of insulin in the culture medium in any of these systems. Rates of free fatty acid and glycerol release were markedly increased in cultured cells, especially when insulin was present in the culture medium. The acute antilipolytic effect of insulin was retained, so that insulin in the test incubation decreased lipolysis by 40-80%. Nevertheless, cell-associated fatty acids were increased in cultured cells and FFA/albumin ratios in the medium often reached potentially toxic levels. The reduction in pentose phosphate shunt activity, lipogenesis, and insulin effect resembles other models of insulin insensitivity. The impaired metabolism is probably due to an intracellular defect. A possible toxic role of either intracellular or extracellular fatty acids cannot be excluded. This system should be a useful model in which to study the cellular mechanisms of insulin insensitivity in adipocytes.-Bernstein, R. S. Insulin insensitivity and altered glucose utilization in cultured rat adipose tissue.
url http://www.sciencedirect.com/science/article/pii/S0022227520400148
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