Marked secretion of pyruvate in human duodenal juice stimulated with pancreozymin or secretin

Pyruvate and lactate in duodenal aspirates were investigated to determine whether they are excreted from human pancreas as substrates for alkaline secretion as is bicarbonate. Secretion of these acids was compared with that of another organic acid, citrate, which is thought to be excreted in close relationship to digestive enzymes. All acids were assayed in the fluid obtained from 11 subjects without pancreatic diseases, before and after sequential intravenous injections of 1 unit/kg pancreozymin and 1 unit/kg secretin. Pyruvate concentrations were markedly increased by each stimulation, especially by secretin, and the cumulative excretions of pyruvate and bicarbonate after secretin stimulation were significantly correlated among the subjects. In contrast, lactate concentrations, although high just after administration of pancreozymin, declined to a considerable extent following each injection, rather similar to those of protein or citrate. These data suggest that pyruvate may be secreted from human pancreatic duct cells similar to bicarbonate secretion through mechanisms related to alkaline secretion.