Circadian rhythm of the in vitro stimulation of adenylate cyclase in rat heart tissue.
Adenylate cyclase activity in rat heart ventricles displayed a circadian rhythm with a maximum around 8:00 h and a minimum around 20:00 h. In vitro stimulation with 0.1 mM of isoprenaline, Gpp(NH)p or forskolin increased the 24-h-mean basal adenylate cyclase activity by 1.7-, 2.7- and 10.7-fold, respectively. The magnitude of the drug-induced stimulation varied significantly with the time of day. However, the drugs did not affect the timing of the circadian maximum or the amplitude (as % of 24-h-mean) of the basal rhythm. The data are the first to show that the response to the in vitro stimulation of the cardiac adenylate cyclase also displays a pronounced circadian rhythm.
Lemmer
B
B
Center of Pharmacology, J.W. Goethe-University, Frankfurt, F.R.G.
Witte
K
K
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002940:Circadian Rhythm; D005576:Colforsin / Q000494:pharmacology; D004789:Enzyme Activation; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains
D005576:Colforsin; D006165:Guanylyl Imidodiphosphate; D000262:Adenylyl Cyclases; D007545:Isoproterenol