Physiol. Res. 49: 213-217, 2000

Glucose as a Lipolytic Agent: Studies on Isolated Rat Adipocytes

T. Szkudelski, K. Szkudelska


Department of Animal Physiology and Biochemistry, University of Agriculture, Poznan, Poland

Received May 4, 1999
Accepted July 21, 1999


Summary
In order to elucidate the direct effect of glucose on lipolysis in isolated rat adipocytes, cells were incubated in a buffer with different concentrations of this sugar: 2, 8 or 16 mmol/l. The increase in glucose concentration from 2 mmol/l to 8 or 16 mmol/l enhanced basal lipolysis by 30% and 47 %, respectively. Epinephrine-induced lipolysis (1 m mol/l) was also increased by 31 % and 32 %, when glucose concentration was increased from 2 mmol/l to 8 or 16 mmol/l, respectively. The rise in lipolysis caused by glucose was restricted by H-89 (an inhibitor of protein kinase A, 30 µmol/l), but insulin (1 nmol/l) had no inhibitory action. The augmentation of lipolysis by glucose did not require its metabolism (as demonstrated using 2-deoxyglucose) and was due to the action of this sugar on the final steps of the lipolytic cascade, particularly on protein kinase A. However, short-term exposure of adipocytes to higher glucose concentrations did not restrict the inhibitory action of insulin on lipolysis induced by epinephrine.


Key words
Adipocytes · Glucose · Lipolysis

Reprint requests

T. Szkudelski, Department of Animal Physiology and Biochemistry, University of Agriculture, Wolynska 35, PL-60-637 Poznan, Poland. e-mail: tszkudel@jay.au.poznan.pl


© 2000 by the Institute of Physiology, Czech Academy of Sciences