Alteration of secretin-stimulated cardiac adenylate cyclase activity in rats with portacaval shunt.
Wistar rats were submitted to portacaval anastomosis (PCA). Control rats were sham-operated and pair-fed (SOPF). After 3 weeks, PCA led to the hypertrophy of right atrium (+50%), left atrium (+67%) and both ventricles (+26%). The response of adenylate cyclase activity to secretin was specifically and markedly decreased in membranes from atria (-51 to 59%) and ventricles (-68 to 69%). These data suggest a decrease in the number of functional secretin receptors in heart considering that: the half-maximal stimulatory secretin concentration was unchanged; glucagon stimulations were unaltered and D,L-isoproterenol stimulations were hardly affected; the Gpp(NH)p-, NaF-, and forskolin-stimulated adenylate cyclase activities were moderately decreased (in ventricles, by 14-28%) or unchanged (in atria).
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D005576:Colforsin / Q000494:pharmacology; D005260:Female; D005934:Glucagon / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D006325:Heart Atria / Q000201:enzymology; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D009206:Myocardium / Q000201:enzymology*; D011167:Portacaval Shunt, Surgical; D051381:Rats; D011919:Rats, Inbred Strains; D012633:Secretin / Q000494:pharmacology*; D012969:Sodium Fluoride / Q000494:pharmacology
D012633:Secretin; D005576:Colforsin; D006165:Guanylyl Imidodiphosphate; D006160:Guanosine Triphosphate; D012969:Sodium Fluoride; D005934:Glucagon; D000262:Adenylyl Cyclases; D007545:Isoproterenol