Studies on pancreatic stones. II. Citrate secretion in the canine pancreatic juice

In a previous study, we found that pancreatic stones could be dissolved in vitro by a citrate solution. We then decided to look for the possible secretion of citrate into the pancreatic juice, and to find a means of increasing it. Pancreatic juice secretion was collected in Thomas fistula dogs submitted to four protocols: basal conditions, secretin stimulation (0.5 and 2.0 U . kg-1 . h-1), caerulein boluses (25 and 100 ng . kg-1) superimposed on 0.5 U . kg-1 . h-1 secretion and intraduodenal citrate infusion (1.05 mmol . kg-1 . h-1). Under basal conditions mean citrate output per 15 min was 0.11 +/- 0.02 mumol. During secretin and caerulein stimulation, citrate output paralleled that of protein, and a linear regression was calculated: Ycitrate = -0.013 + 0.019 Xprotein (mumol/mg). Intraduodenal citrate infusion induced a sharp increase in citrate output which reached 11.5 mumol/15 min, but only 0.12% of the infused citrate amount was secreted into pancreatic juice during 1 h.