Indirect evidence against a contribution of the guanine nucleotide-binding inhibitory component of adenylate cyclase to impaired lipolysis in the epididymal adipose tissue of congenitally obese (ob/ob) mice.
The mixed adrenergic agonist epinephrine, at a 10 microM concentration, stimulated cyclic AMP production and glycerol release in the epididymal adipose tissue of ob/ob male mice. These effects when tested, respectively, after 7 min in the presence and after 60 min in the absence of theophylline were, however, 7- and 5-fold lower than in lean controls. The alpha-adrenergic blocker phentolamine and adenosine deaminase (which destroys extracellular adenosine) did not restore a normal lipolytic response to epinephrine in the adipose tissue of ob/ob mice. These data provide indirect evidence against a hyperactive mechanism in the coupling of alpha-adrenergic receptors and adenosine receptors to Ni, the guanine nucleotide-binding inhibitory component of adenylate cyclase, as the cause of reduced lipolysis in the adipose tissue of ob/ob mice.
Dehaye
J P
JP
Hebbelinck
M
M
Winand
J
J
Christophe
J
J
D000243:Adenosine Deaminase / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000273:Adipose Tissue / Q000187:drug effects; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology*; D005990:Glycerol / Q000378:metabolism; D008066:Lipolysis; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000201:enzymology* / Q000235:genetics; D010646:Phentolamine / Q000494:pharmacology
D000242:Cyclic AMP; D000243:Adenosine Deaminase; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D005990:Glycerol; D004837:Epinephrine; D010646:Phentolamine