The mechanism of the lipolytic action of theophylline in fat cells.
The lipolytic action of theophylline was examined using both intact fat cells and a fat globule system. Theophylline had similar lipolytic actions in both systems. However theophylline did not activate hormone-sensitive lipase in the fat globule system as measured with added Ediol. Pretreatment of the fat globules with phospholipase C suppressed theophylline-induced lipolysis, but phospholipase D had no effect. A theophylline-sensitive system was reconstituted from endogenous fat and a lipase fraction. Inhibitors of theophylline-induced lipolysis such as quinine and propranolol inhibited theophylline binding to artificial lipid micelles. Purine nucleosides such as adenosine, inosine and guanosine inhibited theophylline-induced lipolysis in the fat globule system. These results suggest that theophylline has a lipolytic action similar to that of adrenaline. Both share a lipolytic mechanism additional to that involving the activation of hormone sensitive lipase through the cyclic-AMP dependent protein kinase. Phospholipids play an important role in this additional mechanism.
D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002395:Catecholamines / Q000494:pharmacology; D008066:Lipolysis / Q000187:drug effects*; D008297:Male; D009705:Nucleosides / Q000494:pharmacology; D010739:Phospholipase D / Q000494:pharmacology; D051381:Rats; D013806:Theophylline / Q000494:pharmacology*; D010738:Type C Phospholipases / Q000494:pharmacology
D002395:Catecholamines; D009705:Nucleosides; D013806:Theophylline; D010738:Type C Phospholipases; D010739:Phospholipase D