Sexual dimorphism of isozyme patterns of lactate dehydrogenase and effects of testectomy and ovariectomy on the isozyme distribution in the masseter muscle and tongue of mice

In the masseter muscle, male and female types of isozyme distribution of lactate dehydrogenase (LDH) were clearly detectable by the 40th postnatal day: the percentage of muscle-type LDH isozyme (LDH 5) was statistically higher in the male muscle than in the female one. No sexual difference was found in the distribution in the tongue. In the testectomized mice, the distribution pattern of LDH isozymes was shifted to the female type in the masseter muscle, but testectomy had no effect on the tongue. On the other hand, ovariectomy never affected the distribution patterns of LDH isozymes in either masseter muscle or tongue of female mice