Insulin receptor binding and insulin action in human fat cells: Effects of obesity and fasting

Insulin binding and action were studied in fat cells from the gluteal region of young healthy subjects. Fat cells from females were larger than those of males, had higher insulin receptor binding and higher rates of noninsulin-stimulated and maximally insulin-stimulated rates of methylglucose transport and glucose metabolism when these data were expressed per cell number. However, when insulin binding and insulin effects were expressed per cell surface, which may be physiologically more relevant, no sex differences were found in insulin binding and glucose transport, whereas noninsulin-stimulated and maximally insulin-stimulated glucose metabolism was still significantly increased in female fat cells. The latter indicates postreceptor differences in glucose metabolism between females and males. The insulin concentrations causing half-maximal responses (a measure of the sensitivity to insulin) of glucose transport, glucose metabolism and lipolysis were similar in fat cells from the two sexes, which is consistent with the comparable values of insulin receptor binding when adjusted to cell surface. Studies of rate-determining steps for the glucose utilization of human fat cells showed that glucose transport was not the rate-limiting step at physiological glucose concentrations. Moreover, at physiological glucose levels, glucose metabolism exhibited a decreased maximal insulin responsiveness and an increased insulin sensitivity when compared with glucose metabolism at low glucose concentrations at which glucose transport is rate limiting for the fat cell glucose utilization.

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Reversal of insulin resistance in adipose tissue of non-insulin-dependent diabetics by treatment with diet and sulphonylurea

Acta Endocrinologica ◽

10.1530/acta.0.1080085 ◽

1985 ◽

Vol 108 (1) ◽

pp. 85-90 ◽

Cited By ~ 16

Author(s):

Jan Bolinder ◽

Jan Östman ◽

Peter Arner

Keyword(s):

Insulin Resistance ◽

Adipose Tissue ◽

Insulin Receptor ◽

Receptor Binding ◽

Insulin Action ◽

Conventional Treatment ◽

Glucose Oxidation ◽

Dependent Diabetes Mellitus ◽

Insulin Receptor Binding ◽

Insulin Dependent

Abstract. The effect of conventional treatment on insulin action in subcutaneous adipose tissue was studied in 6 patients with non-insulin-dependent diabetes mellitus (NIDDM). Insulin receptor binding and the effect of the hormone on glucose oxidation were determined before and after 6–14 months of treatment with diet plus sulphonylurea. Glycaemic control and in vivo insulin sensitivity were significantly improved by the treatment. Before treatment, the adipocyte insulin receptor binding and the sensitivity to insulin stimulation of adipose tissue glucose oxidation were normal and did not change after treatment. In contrast, the maximum insulin-induced glucose oxidation was markedly decreased before treatment, whereas it was totally normalized after treatment. The conclusion is that insulin resistance in adipose tissue of NIDDM subjects is solely due to post-receptor defects in insulin action. This resistance is completely off-set by conventional treatment with diet plus sulphonylurea.

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