Effects of verapamil on lipolysis due to dibutyryl cyclic AMP.
The effects of verapamil, a calcium antagonist, on lipolysis in isolated rat adipocytes were studied. Verapamil (100 microM) potentiated lipolysis due to dibutyryl cyclic AMP (Bt2cAMP) at submaximal concentrations, with or without extracellular Ca2+. Lipolysis due to 0.5 mM-Bt2cAMP was potentiated by verapamil in a dose-dependent manner up to 200 microM, whereas at concentrations higher than 100 microM the stimulatory effect of verapamil was progressively diminished with or without extracellular Ca2+. Verapamil showed only an inhibitory effect on lipolysis due to adrenaline (0.1-10 microM) or 3-isobutyl-1-methylxanthine (IBMX; 25-200 microM). The stimulatory effect of verapamil on lipolysis due to Bt2cAMP was not blocked by alpha-adrenergic antagonists. These results suggest (i) that verapamil has a biphasic effect on lipolysis due to Bt2cAMP and only an inhibitory effect on that due to adrenaline or IBMX, and (ii) that extracellular Ca2+ or alpha-adrenergic receptors are not involved in the action of verapamil.
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology*; D000242:Cyclic AMP / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D066298:In Vitro Techniques; D008066:Lipolysis / Q000187:drug effects*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014700:Verapamil / Q000494:pharmacology*
D003994:Bucladesine; D014700:Verapamil; D000242:Cyclic AMP; D015056:1-Methyl-3-isobutylxanthine; D004837:Epinephrine