Renal Ca2+ + Mg2+ ATPase in congestive heart failure due to diabetes.
The authors have previously shown that atrial natriuretic peptide (ANP) mediates its cellular effects in part by changes in Ca2+ homeostasis in kidney cortex and that Ca2+ + Mg2+ ATPase is linked to ANP receptors, being reciprocally modulated by the guanylate cyclase system. The present study was designed to examine the status of this coupling in diabetes-induced congestive heart failure and the effect of its alterations on the functional integrity of the renal cell. Ca2+ + Mg2+ ATPase and guanylate cyclase were tested in hypertensive-diabetic rats (D + H), which develop congestive heart failure (CHF) at ten weeks following streptozotocin (65 mg/kg) injection and abdominal aortic constriction. The ATPase activity was measured by the release of 32P from [gamma-32P]ATP in the medium. While the guanylate cyclase activity was decreased very rapidly in the hypertensive-diabetic group, the sensitivity of the Ca2+ pump to ANP was increased at an early stage (three weeks) and decreased at a late stage (ten weeks) of CHF. The authors conclude that a defect in coupling between the Ca2+ pump and the ANP-receptor system as observed in the D + H group may contribute to the development of nephropathy and CHF.
Sahai
A
A
Division of Cardiovascular Sciences, St Boniface General Hospital Research Centre, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Weiser
S J
SJ
Ganguly
P K
PK
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D017301:Ca(2+) Mg(2+)-ATPase / Q000187:drug effects / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000150:complications* / Q000201:enzymology; D003925:Diabetic Angiopathies / Q000201:enzymology* / Q000209:etiology; D006162:Guanylate Cyclase / Q000187:drug effects / Q000378:metabolism*; D006333:Heart Failure / Q000201:enzymology* / Q000209:etiology; D006973:Hypertension / Q000201:enzymology; D007668:Kidney / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D009320:Atrial Natriuretic Factor; D017301:Ca(2+) Mg(2+)-ATPase; D006162:Guanylate Cyclase