EFFECTS OF GLUCOSE INFUSIONS ON ADIPOSE TISSUE LIPOGENESIS IN MAN

Abstract

Abstract Incorporation of label from glucose‐1‐ 14 C with different concentrations of non‐labelled glucose, and acetate‐U‐ 14 C, with or without added non‐labelled glucose, into carbon dioxide, fatty acids and glyceride‐glycerol was measured in human subcutaneous adipose tissue taken from patients with clinically “well‐controlled” juvenile diabetes mellitus or from controls. The effects of infusion of glucose in the controls and glucose plus insulin in the diabetic patients on the day preceding adipose tissue biopsy, and of the addition of insulin or citrate in vitro, were investigated. In normals glucose infusions before biopsy caused an increase in in vitro response to insulin of carbon dioxide formation from labelled glucose and an increased incorporation of label from acetate (with 10 mM glucose) into carbon dioxide and fatty acids. In diabetic patients such an increase of label in carbon dioxide and fatty acids was found with labelled glucose (1 mM), and the resulting values were as high as those of the normals who had not received glucose before sampling, but they did not reach the values found in normals who had been given glucose. A similar remaining deficiency after glucose infusion was found in the diabetic tissues in incorporations of labelled acetate (with 10 mM glucose), the values being as high as those of normals without preceding glucose infusions but lower than those of glucose‐treated normals. The variability of insulin response of human adipose tissue in different metabolic situations may indicate that adipose tissue glucose uptake contributes to determining glucose tolerance in man. Furthermore, adipose tissue in man may be an important site for glucose lipogenesis during abundance of glucose while in other metabolic situations the liver may well be of relatively greater importance for lipogenesis.