Effects of hypophysectomy on tissue alkaline phosphatase in the rat

To examine the effect of hypophysectomy on tissue alkaline phosphatase (EC 3.1.3.1) activity, studies were performed on mature rats. Hypophysectomy reduced the alkaline phosphatase activity in duodenum, kidney, and femoral bone. The decrease of alkaline phosphatase was greater in the intestine than in other organs studied. Intestinal alkaline phosphatase fell rapidly within 4 days post-hypophysectomy. In contrast, bone and kidney alkaline phosphatase activity had an initial lag period for 4 days after the hypophysectomy. Serum alkaline phosphatase also declined after hypophysectomy. The bone isoenzyme of serum alkaline phosphatase was reduced to a greater extent than the intestinal isoenzyme.