[Effect of varying the vitamin E allowance on the contractile function of the heart muscle]

Experimental rats received diets containing varying amounts of vitamin E (100, 12.5 and 0 mg alpha-tocopherol acetate/kg food) during 4 months. It was found that although subnormal intake (12.5 mg/kg) of DL-alpha-tocopherol resulted in a 60% decrease of its concentration in the rat blood serum, it induced a significant lowering in the hemolytic stability of red blood cells, pronounced impairment of the rats' myocardial contractile function was observed as compared to the animals which received optimal doses of the vitamin (100 mg/kg food). The impairment was expressed in a decrease of the tension developed, depression of Starling's curve (the ratio between the initial length and the tension developed), the lowering of the myocardial resistance to Ca2+ excess, resulting in a more rapid development of the calcium-induced contracture. An increased vitamin E deficiency (0 mg DL-alpha-tocopherol/kg food), an 11-fold lowering of tocopherol concentration in the blood and a drastically enhanced hemolysis of red blood cells did not lead to a further impairment of the myocardial contractile function parameters studied.