Memory of the rhythmic change in activity of duodenal alkaline phosphatase in rats.

Studies were made on memory of the rhythmic change in activity of duodenal alkaline phosphatase in rats. During starvation, the peak enzyme activity decreased gradually disappearing in 4 days. The peak activity of duodenal alkaline phosphatase was retained by feeding starch diet for 4 days instead of starvation for 4 days, but not by feeding casein diet for the same period. Starvation for one day after feeding casein diet for 4 days resulted in disappearance of the peak activity. However, the peak activity was still retained after one day of starvation after 4 days on starch diet. Therefore, starch feeding appears to be important in the memory of the rhythmic change in activity of duodenal alkaline phosphatase.