Activity of alkaline phosphatase in the major salivary glands of mice at various ages of postnatal life, and during pregnancy and lactation.

Activity of alkaline phosphatase in the major salivary glands of male and female mice at various ages of postnatal life, and in females during lactation was studied histochemically. Enzyme activity was not detected on the day of birth, but was found in the terminal tubules of all major salivary glands during the first postnatal week. Alkaline phosphatase activity was increasing gradually with age and a definitive enzymatic pattern was observed by the age of 6 weeks. No difference in enzyme activity was found among the major salivary glands of young adult and old animals. The parenchyma of fully differentiated submandibular glands showed clear sexually dimorphic patterns of alkaline phosphatase activity. During pregnancy, a significant increase of alkaline phosphatase activity was detected in submandibular gland. From gestation day 15 to the end of pregnancy, enzymic pattern of granular convoluted tubules of pregnant females was the same as in the adult males. Histochemical masculinization of the submandibular gland during pregnancy suggests that besides androgens also progesterone exerts masculinization of the murine submandibular salivary gland.