Abstract
Alkaline phosphatase activity of the mouse duodenum normally increases 20-fold between 13 and 20 days. Activity at 15 days is raised two to three times above normal by administering actinomycin D, puromycin, or the aminonucleoside of puromycin at 13 or 14 days. Phosphatase activity in the jejunum and kidney are not similarly affected.