MYOCARDIAL PROTEINS IN DOGS OF VARIOUS AGES.

Abstract

Protein fractions of the hearts of dogs of different ages were examined and levels of desoxyribose, ribose and myoglobin were determined as well. There were 9 dogs in each of 4 groups: I, one year old or less; II, 2-4 years of age; III, 5-8 years of age; and, IV, 9 years or older. The desoxyribose concentration of the oldest group of dogs was 30% less than that of the youngest. Ribose concentration did not differ with age. Concentration of the fraction corresponding to myosin was significantly increased in the oldest group while the fraction corresponding to contractin showed a decrease that was not statistically significant, and that corresponding to actomyosin remained constant. Myoglobin concentration increased with each age group. The data suggest that cellular hypertrophy occurs with aging of the myocardium of dogs. Dogs in the oldest age group exhibit no impairment in ability to maintain a normal myocardial protein content although some age-dependent changes seem apparent.