title: Decreased myocardial function and myosin ATPase in hearts from diabetic rats.
abstract: The effect of diabetes on cardiac function was determined in isolated rat hearts. Diabetes was induced by injection of alloxan (doses ranged from 37.5 to 60 mg/kg body wt), and the heart were removed and perfused in the working heart preparation. Doses of alloxan ranging from 37.5 to 42 mg/kg did not consistently alter cardiac function even though serum glucose was elevated and serum thyroid hormones were reduced. Injection of 45 mg/kg of alloxan caused a large increase in serum glucose and a larger decrease in thyroid hormones. In this case, ventricular function was more consistently depressed after 1-2 wk. Function was not altered 48 h after injection of 60 mg kg of alloxan. However, when animals were given 60 mg/kg of alloxan and then maintained on insulin for 7 days, depressed cardiac function developed within 4 days after the insulin treatment was stopped. The decline in function involved a decrease in heart rate peak systolic pressure, and left ventricular +dP/dt. It was associated with greatly reduced serum thyroid hormones (both T3 and T4) and lower ventricular Ca2+-activated myosin ATPase activity. Fasting of rats for 4 days also resulted in decreased serum T3 and T4, depressed cardiac function (although heart rate was unchanged), and lower Ca2+-activated myosin ATPase activity.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology / Q000503:physiopathology*; D005947:Glucose / Q000378:metabolism; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate; D008297:Male; D009206:Myocardium / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D001786:Blood Glucose; D000251:Adenosine Triphosphatases; D005947:Glucose