The role of insulin and thyroid hormones in the regulation of muscle growth and protein turnover in response to dietary protein in the rat

摘要: 1. We have investigated the relations between changes in plasma insulin and 3,5,3'-triiodothyronine (T3), muscle growth protein turnover rat response to diets of varying concentrations. 2. Young rats were fed ad lib. on a control (180 g casein/kg) diet or low-protein containing 80, 45 0 casein/kg four separate experiments. Measurements made food intakes, body-weight rates, vivo, insulin, free total T3. 3. The intakes 80 groups variable, with group consuming either same more than controls, less controls. Body-weight skeletal-muscle rates varied but not energy which turn reflected both dietary composition intake, hyperphagic growing almost normally losing mass. 4. Changes accompanied by parallel synthesis degradation, as well concentrations T3, extent that all these variables highly correlated each other. 5. Partial correlation analysis was used interactions variables. This indicated had no identifiable influence growth. In contrast appeared stimulate directly increasing RNA content inhibiting proteolysis, T3 levels. Insulin stimulated other turnover; stimulating activity particularly at low levels, hormones proteolysis. 6. These apparent are shown be consistent main part previous studies mechanism action possibility cannot discounted anabolic measured involved, direct muscle.