Lipid peroxidation inhibits norepinephrine-stimulated lipolysis in rat adipocytes. Reduction of beta-adreno-ceptor number.
The effect of lipid peroxidation on lipolysis depends on the intactness of the adipocyte plasma membrane. In the intact cells, the norepinephrine-stimulated lipolysis was inhibited, while the basal one was elevated. In the lysed cells, lipid peroxidation had no effect upon hormone-stimulated lipolysis, but the basal one was strongly inhibited. The effects of free radical damage (iron plus ascorbate ions) were compared to those of malondialdehyde, a non-radical product of lipid peroxidation. Although qualitatively similar, deterioration of plasma membrane induced by malondialdehyde was much lower than by free radicals. The changes in lipolytic response to norepinephrine were accompanied by a drastic reduction in the number of beta-adrenergic receptors.
Rejholcová
M
M
Charles University, Faculty of Medicine, Laboratory for Endocrinology and Metabolism, Prague, Czechoslovakia.
Wilhelm
J
J
Svoboda
P
P
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D007501:Iron / Q000494:pharmacology; D008054:Lipid Peroxides / Q000378:metabolism*; D008066:Lipolysis / Q000187:drug effects*; D008297:Male; D008314:Malonates / Q000494:pharmacology*; D008315:Malondialdehyde / Q000494:pharmacology*; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*
D008054:Lipid Peroxides; D008314:Malonates; D011943:Receptors, Adrenergic, beta; D008315:Malondialdehyde; D007501:Iron; D001205:Ascorbic Acid; D009638:Norepinephrine