Catecholamine-induced lipolysis was investigated in adipocytes obtained before and after 30 min of exercise from 10 insulin-treated type I (insulin-dependent) diabetic men and 10 male matched control subjects. The α2-adrenoceptor-mediated antilipolytic effect of catecholamines was normal, but the β-adrenoceptor-mediated lipolytic sensitivity was increased 10-fold (P < .01) in diabetic subjects before and after exercise. The latter correlated inversely (r > .7) with the circulating norepinephrine level, which was significantly reduced in diabetic subjects. Basal lipolysis and lipolysis activated at different steps distal to the β-receptor were similar in the two groups. There was no major change in the total number of β- and α-adrenoceptors in the diabetic patients. However, the proportion of high-affinity β-adrenoceptors was significantly increased in these patients compared with control subjects. In the diabetic patients, ∼50% of the β-adrenoceptors were in a high-affinity state, compared to ∼30% in the control subjects (P < .025). In diabetic subjects there was an enhanced plasma glycerol response to exercise, despite a blunted plasma norepinephrine response. The data suggest enhanced sensitivity of catecholamine-induced lipolysis in type I diabetes due to an increase in the number of high-affinity (i.e., coupled) β-adrenoceptors in fat cells. This mechanism may be due to low levels of circulating norepinephrine and may also explain the exaggerated lipolytic response to exercise in the diabetic state.
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Original Articles|
April 01 1989
Abnormal Action of Catecholamines on Lipolysis in Adipocytes of Type I Diabetic Patients Treated With Insulin
Hans Wahrenberg;
Hans Wahrenberg
Department of Medicine and the Research Center, Huddinge Hospital
Karolinska Institute, Stockholm, Sweden
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Fredrik Lönnqvist;
Fredrik Lönnqvist
Department of Medicine and the Research Center, Huddinge Hospital
Karolinska Institute, Stockholm, Sweden
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Peter Engfeldt;
Peter Engfeldt
Department of Medicine and the Research Center, Huddinge Hospital
Karolinska Institute, Stockholm, Sweden
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Peter Arner
Peter Arner
Department of Medicine and the Research Center, Huddinge Hospital
Karolinska Institute, Stockholm, Sweden
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Address correspondence and reprint requests to Peter Arner, MD, Department of Medicine, Huddinge Hospital, S-141 86 Huddinge, Sweden.
Diabetes 1989;38(4):524–533
Article history
Received:
February 29 1988
Revision Received:
October 25 1988
Accepted:
October 25 1988
PubMed:
2647559
Citation
Hans Wahrenberg, Fredrik Lönnqvist, Peter Engfeldt, Peter Arner; Abnormal Action of Catecholamines on Lipolysis in Adipocytes of Type I Diabetic Patients Treated With Insulin. Diabetes 1 April 1989; 38 (4): 524–533. https://doi.org/10.2337/diab.38.4.524
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