LACTIC DEHYDROGENASES AND MUSCULAR DYSTROPHY IN THE CHICKEN

Abstract

It has been shown that in dystrophic chickens the muscles contain a higher per cent of H (heart) type LDH than do the muscles of normal chickens. This change appears to represent a block in the development of the normal enzymatic pattern of the muscle cells, since the H type of enzyme is the embryonic form in the chicken. Some correlation has been obtained between the severity of the dystrophy in the chicken and the composition of the LDH''s in most of the muscles. The more severe the disease the more embryonic is the LDH pattern in the muscles of the dystrophic animal. It has also been found that in the normal chicken different skeletal muscles havse widely varying compositions of M and H forms of LDH. Not only is there a difference in composition of the LDH in the skeletal muscles of dystrophic chickens but also there is a significant decrease in total level of LDH per unit wet weight in the diseased birds. Furthermore, nearly all of the skeletal muscles of the dystrophic chickens have an increased per cent of H enzyme, which is comparable to normal embryonic muscles. The disease in the chicken is compared to that occurring in humans and in mice, and a possible mechanism of its genesis is proposed.