Developmental changes of calcium-stimulated adenosine triphosphatase in rat submandibular gland

Developmental changes in Ca2-+ ATPase activity were determined in submandibular glands of the rat from the fetus to the 300-day-old rat. Ca2+-ATPase in the homogenate fraction showed a rapid increase from the fetus to the 5-day-old rat, and from the 20- to 30-day-old rat. In the microsomal fraction, enzyme activity increased from the fetus to the 10-day-old rat, and after that is remained at almost the same level. Oscillatory phenomena of Ca2+-ATPase were observed in zymogen and mitochondrial fractions.