OXIDATIVE AND HYDROLYTIC ENZYMES OF HOMOZYGOUS DYSTROPHIC AND HETEROZYGOUS MUSCLE OF THE HOUSE MOUSE

Histochemical procedures were used for the identification of oxidative and hydrolytic enzymes of homozygous dystrophic (genotype, dydy) and heterozygous (genotype, Dydy) muscles of the house mouse. In adult heterozygous muscle and muscle of a Swiss albino mouse there was usually a reciprocal relationship between phosphorylase and lactate dehydrogenase, i.e., weak lactate dehydrogenase reactions in the majority of fibers of the vastus lateralis and a stronger phosphorylase reaction. Weak to strong lactate dehydrogenase reactions were identified in fibers of the rectus femoris. In heterozygous muscle of young mice 20 days of age, a reciprocal relationship between lactate dehydrogenase and phosphorylase was not observed. Reciprocity between phosphorylase and lactate dehydrogenase was not always evident in fibers of homozygous muscles, e.g., groups of homozygous fibers frequently exhibited both strong phosphorylase and lactate dehydrogenase reactions whereas other fibers reacted weakly for phosphorylase or not at all and strongly for lactate dehydrogenase. Small fibers reacted either weakly or strongly for dehydrogenases. One of the striking features which homozygous fibers usually showed was uniformly strong dehydrogenase reactions (e.g. lactate, glutamate, succinate) and diphosphopyridine nucleotide linked diaphorase reactions. Strong glucose-6-phosphate dehydrogenase reactions were frequently identified in homozygous dystrophic fibers whereas weak reactions or no reactions at all were seems in heterozygous fibers. Atrophic fibers of homozygous dystrophic muscles exhibited intense indoxyl acetate esterase and acid phosphatase reactions. Weak adenosine triphosphatase reactions were seen in fibers of both heterozygous and homozygous dystrophic muscle, and strong reactions in connective tissues and blood vessels. Interfibrillar connective tissue of homozygous muscle was abundant and exhibited intense acid phosphatase reactions, whereas connective tissues of heterozygous muscle were less concentrated and exhibited weak acid phosphatase reactions.