title: Association of adenylate cyclase inhibition by NaF with loss of a factor in rat heart sarcolemma.
abstract: Heart sarcolemma from different animals was isolated for studying the effect of NaF on membrane-bound adenylate cyclase activity. Unlike dog and rabbit heart, a depression of adenylate cyclase by NaF was observed in sarcolemma from rat heart. There was a progressive attenuation of the NaF ability to stimulate the enzyme at different steps of the sarcolemmal isolation procedure. The activation by epinephrine in the presence of Gpp(NH)p also decreased progressively but unlike NaF, this agent did not show an inhibition of the enzyme. The inhibitory action of NaF was not reversed upon the treatment of heart membranes with deoxycholate or by Ca2+. Lubrol extract (supernatant) of a particulate fraction from rat heart, which showed NaF activation, returned the stimulatory response of the sarcolemmal adenylate cyclase to NaF. These results suggest that some regulatory factor is required for the stimulation of adenylate cyclase by NaF in myocardium and rat heart is susceptible for the loss of such a factor during the sarcolemmal isolation by the hypotonic shock-LiBr treatment method.
mesh_terms: D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D002118:Calcium / Q000378:metabolism; D004285:Dogs; D004837:Epinephrine / Q000494:pharmacology; D006321:Heart / Q000187:drug effects; D009206:Myocardium / Q000201:enzymology*; D011092:Polyethylene Glycols; D011817:Rabbits; D051381:Rats; D012508:Sarcolemma / Q000201:enzymology*; D012969:Sodium Fluoride / Q000494:pharmacology*; D012995:Solubility; D013045:Species Specificity
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D011092:Polyethylene Glycols; C005092:lubrol; D012969:Sodium Fluoride; D002118:Calcium; D004837:Epinephrine