A non-neural regulatory effect on the metabolic differentiation of the skeletal muscles, effect of castration and testosterone administration on the skeletal muscles of the rat

Abstract

1. 1. The LDH isozyme pattern was investigated during postnatal development in red, white and absolutely androgenic-dependent muscles of rat. Its alteration were determined after castration performed at different times of life. 2. 2. The differences of LDH activity of red and white muscle characteristic of adult rats developed in the 6th–8th week of life. After castration the total LDH activity did not alter in any of the types of muscles. 3. 3. After castration there was a shift toward oxidative H subunits. This was most pronounced between the 6th and 8th week of life. In mature rats castration was not effective. 4. 4. Testosterone propionate 100 μg/100 g body weight/day moderated the accumulation of H, caused by castration. In the levator ani it completely restored the subunit pattern characteristic of the normal animals. 5. 5. The testicular hormones, beside their anabolic effect, have some influence on the metabolic differentiation of the skeletal muscles. This effect can of the differentiation of the gycolytic fibre types.