Diabetic type of cardiomyopathy in food-restricted rats

We have demonstrated that food restriction that is associated with weight loss can produce a type of cardiac dysfunction similar to that produced by diabetes. As in diabetic atria, the food-restricted atria had a 2-fold increase in contraction force, rate of force development, and rate of force decline compared with controls. Both food-restricted and diabetic atria could tolerate anoxia better than controls. The contractile function of the whole perfused heart from the food-restricted rat was reduced, as in the case of the diabetic heart. As the left ventricular volume was increased, the left ventricular developed pressure and the rate of rise and fall in pressure were significantly reduced in both food-restricted and diabetic hearts, compared with those of age- and weight-matched controls. The positive inotropic responses of atria and whole perfused heart to increasing concentrations of extracellular calcium were similarly altered in food-restricted and diabetic hearts. The possible molecular mechanisms of these findings and some of the differences observed between food-restricted and diabetic hearts are discussed.