Antilipolytic action of insulin in abdominal adipocytes of obese subjects before and during energy restriction. Influence of adenosine deaminase
Kather, H.; Scheurer, A.; Schlierf, G.
International Journal of Obesity 11(2): 191-200
1987
ISSN/ISBN: 0307-0565 PMID: 3301711 Document Number: 289521
Influence of prolonged energy restriction (1250 kJ for 4 weeks) on insulin's antilipolytic action was investigated in abdominal adipocytes of obese subjects. Basal lipolytic rate was increased 35 times after prolonged energy restriction in absence or presence of adenosine deaminase (1.6 mu g/ml) and was associated with a corresponding increase in maximum response to insulin. To identify dietary influences that selectively affect insulin action the effects of insulin were compared with those of other antilipolytic agents in the presence of adenosine deaminase. Maximally effective concentrations of prostaglandin E2, clonidine and N6-phenylisopropyladenosine almost completely suppressed glycerol release before and during starvation; extent of inhibition was related to basal activity by the same linear relation in all experimental settings. Insulin only partly depressed glycerol release and the relations between basal activity and response to maximum concentrations of insulin were significantly different before and during starvation in the presence of adenosine deaminase indicating that starvation selectively influences insulin action via mechanisms that are unrelated to the effects of other antilipolytic compounds. It is concluded that the main effect of energy restriction on the antilipolytic action of insulin is an apparent one which is secondary to increased lipolytic activity. Direct dietary effects on insulin action became apparent in absence of endogenous adenosine. Effects limit the maximum response to insulin and may be due to changes after binding but could also reflect an intrinsic property of the antilipolytic action of insulin.