AJP - Heart and Circulatory Physiology, Vol 245, Issue 6 1039-H1042, Copyright © 1983 by American Physiological Society
Effects of prostaglandin E1 in diabetic heart
T. B. Miller Jr
Isolated perfused hearts from normal and alloxan-diabetic rats were studied
to determine the effects of prostaglandin E1 (PGE1) on phosphorylase
activation in the insulin-deficient state. Perfusion of hearts from normal
and diabetic rats with 3 X 10(-5) M PGE1 for the final 2 min resulted in
activation to the same extent of adenosine 3',5'-cyclic monophosphate
(cAMP) accumulation, cAMP-sensitive protein kinase, and phosphorylase
kinase. Although phosphorylase activation was somewhat suppressed in both
the normal and diabetic heart, PGE1 produced a 36% increase in
phosphorylase a in normal hearts and a 44% increase in phosphorylase a in
diabetic hearts. The decreased effectiveness of phosphorylase activation by
PGE1 appears to be located beyond activation of phosphorylase kinase and
perhaps involves an alteration in phosphorylase sensitivity to
phosphorylase kinase. Further, the activation of phosphorylase by
phosphorylase kinase is hypersensitive in hearts of diabetic rats, perhaps
due to a diabetes-related alteration in calcium metabolism.
