Effect of hormones and environmental factors on lactic dehydrogenases.

Abstract

There are two types (M and H) of lactic dehydrogenase that are found in most animals. The M-type is found largely in the more anaerobic tissues, such as voluntary skeletal muscles; the H-type is found in aerobic tissues, such as cardiac muscle. In the immature uterus, the level of M units is considerably less than that found in the mature uterus. Injection of estradiol leads to a marked increase in M units in the immature uterus, but there is no significant change in the concentration of the H form. Testosterone and progesterone, in contrast, promote a proportional increase in the two lactic dehydrogenases in the immature uterus. Testosterone, however, induces a selective synthesis of M units in the seminal vessels of the immature rat. Hypophysectomy leads to a decrease in M units of skeletal muscle. The effects of various hormones on the composition of lactic dehydrogenase of the rat and chicken will be summarized.