Plasma concentration of secretin and gastric secretion following intraduodenal calcium infusion in man.

The aim of the present study was to test whether the previously demonstrated release of immunoreactive plasma secretin following intraduodenal bile infusion could be mediated by the calcium content of the bile. The gastric acid secretion and the serum concentration of gastrin, ionized and total calcium, calcitonin, and parathyroid hormone were also measured. A total amount of 93 mg calcium was infused intraduodenally in eight healthy volunteers during constant gastric aspiration. No effect was seen on the concentration of immunoreactive plasma secretin or serum gastrin levels in peripheral blood. The total serum calcium concentration decreased slightly during the infusion and increased immediately thereafter. Ionized serum calcium increased throughout the experiment, the increase being significant only after the calcium infusion was stopped. No effects were observed on the serum concentrations of calcitonin and parathyroid hormone.