Electrolyte and nitrogen changes in skeletal muscle of developing rats

Abstract

Rats 1–45 days old were studied. Plasma Na and Cl concentrations changed little with age, whereas K concentration decreased. Total water content and total Na and Cl concentrations in muscle decreased progressively, whereas total K concentration increased during maturation. Intracellular Na concentration decreased whereas K concentration did not change during maturation. Adult muscle electrolyte values were attained at approximately 45 days. The changes in electrolyte and nitrogen content of muscle during maturation are discussed in relation to histological changes in this tissue with age.