Elevated cholesterol in tissues of chicken embryos with hereditary myotonic muscular dystrophy

The cholesterol content of muscle, liver, serum, and brain was examined both in embryos of chickens with hereditary muscular dystrophy and in normal control embryos between 9 and 16 days in ovo. The superficial pectoral muscles, which are severely affected by muscular dystrophy later in development, have a significantly higher cholesterol content than those of normal embryos at all ages examined. In contrast, the cholesterol content of thigh muscles that are not severely affected by the dystrophic process is no different from that of control embryos. The cholesterol contents of liver and serum from dystrophic embryos are also increased, but the cholesterol content of the brain is not. The increased cholesterol contents of liver and serum are due to proportionate increases of both free cholesterol and cholesteryl esters. In contrast, in superficial pectoral muscles the ratio of cholesteryl esters to free cholesterol is significantly increased. These data indicate that, in addition to the elevated cholesterol in the liver and serum of dystrophic embryos, the regulation of cholesteryl ester content in the dystrophic pectoral muscles is abnormal.