AJP - Regulatory, Integrative and Comparative Physiology, Vol 250, Issue 3 358-R364, Copyright © 1986 by American Physiological Society
Alterations in beta-adrenergic stimulation of myocardial adenylate cyclase in endotoxic rats
F. D. Romano and S. B. Jones
The effect of in vivo endotoxin administration on adenylate cyclase in rat
ventricular membranes was studied. Basal, fluoride-, and
5'-guanylylimidodiphosphate-stimulated adenylate cyclase activities were
not affected throughout the period of endotoxicosis.
Isoproterenol-stimulated adenylate cyclase activity was not different at
0.5 or 3 h after endotoxin. At the agonal stage, the isoproterenol
dose-response curve was shifted significantly to the right in myocardial
membranes from endotoxic rats, but there was no significant decrease in
maximum stimulated activity. These data indicate that endotoxicosis does
not inhibit the adenylate cyclase enzyme system but does decrease
stimulation of adenylate cyclase via beta-adrenergic receptors when the
animal is approaching death.
