The action of secretin and pancreozymin on small-intestinal alkaline phosphatase

Abstract

SUMMARYThe hormones secretin and cholecystokinin-pancreozymin (CCK) have been shown to release brush-border alkaline phosphatase into the small-intestinal lumen in the human subject.In contrast to the disaccharidases, large amounts of alkaline phosphatase are present in human duodenal juice. The range has been established in normal subjects. Following the intravenous administration of both secretin and CCK-pancreozymin there is a large rise in the output of alkaline phosphatase in human duodenal juice. These rises are also present in patients with complete obstruction of the common bile and pancreatic ducts, and since the pancreatic juice of man contains negligible amounts of alkaline phosphatase, it is clear that both hormones must cause small-intestinal alkaline phosphatase to be released into duodenal juice. The isoenzyme characteristics of bile, smallintestinal, and pancreatic alkaline phosphatase have been established, and isoenzyme studies used to confirm this new action of secretin and CCK-pancreozymin.

Alkaline Phosphatases in Biology and Medicine

“…Relation between digestion and absorp tion of dietary fat and AP is further strength ened by an observation that intravenous ad ministration of both secretin and cholecystokinin leads to a marked increase in AP in the intestinal content [82], This rise also occurs when there is a complete obstruction of the biliary and pancreatic duct [82], Administra tion of secretin and cholecystokinin did not increase AP in the bile from a patient with a T tube in the common bile duct [83]. Both these hormones are released by intraduodenal fat.…”

Changes of Serum Alkaline Phosphatase Isoenzymes in Fasted Rats.

“…In the case of ALP in the intestine, the stability of intestinal ALP mRNA may also be lowered under fasting conditions. In addition, as Warnes et al (31) postulated that the rise in intestinal ALP after the ingestion of fat was stimulated by the secretion of secretin and cholecystokinin, the changes in secretin and cholecystokinin under fasting conditions may relate to the decrease in intestinal ALP.…”

Tests of Exocrine Pancreatic Function

“…To date these isoenzymes have not been identified in the plasma. They are not present in pancreatic juice and the rise in duodenal juice alkaline phosphatase following secretin and CCK-PZ is attributable to the intestinal isoenzyme released from the duodenal mucosa (Warnes et al, 1974). The same isoenzyme is present in faeces (Horrigan and Danovitch, 1974).…”