Cardiac membrane Ca(2+)-transport in alloxan-induced diabetes in rats.
In order to determine if cardiac membrane Ca(2+)-transport activities are altered in chronic diabetes induced by alloxan, rats were given an intravenous injection of 65 mg/kg and the hearts were used 8 weeks later. Some 4 weeks, diabetic animals were injected with insulin (3 U/day) for 4 weeks. Both sarcolemmal (SL) and sarcoplasmic reticulum (SR) membranes were isolated from the ventricular tissue and their Ca(2+)-transporting activities were determined. SL Na(+)-dependent Ca2+ uptake, ATP-dependent Ca2+ uptake and Ca(2+)-stimulated ATPase activities were depressed in the diabetic heart. Likewise, SR ATP-dependent Ca2+ uptake activity in the diabetic heart was markedly decreased in comparison to the control preparations. These defects in diabetic SL and SR Ca(2+)-transport activities were prevented by treatment of diabetic animals with insulin. The results from the alloxan-rat model of diabetes support the view that membrane abnormalities with respect to Ca2+ handling may lead to the occurrence of intracellular Ca2+ overload and the development of diabetic cardiomyopathy.
Golfman
L S
LS
Division of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, Manitoba, Canada.
Takeda
N
N
Dhalla
N S
NS
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D006321:Heart / Q000187:drug effects; D017136:Ion Transport / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012508:Sarcolemma / Q000187:drug effects* / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000187:drug effects* / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D019831:Sodium-Calcium Exchanger
D002352:Carrier Proteins; D019831:Sodium-Calcium Exchanger; D012964:Sodium; D000252:Calcium-Transporting ATPases; D002118:Calcium