Blackwell Publishing Journal Backfiles 1879-2005
SUMMARY 1. Pancreatic secretion has been monitored in the isolated, blood-perfused canine pancreas, and the effects of depletion of serum calcium by infusion of EGTA on the increases in secretion produced by intra-arterial injections of dopamine and secretin have been investigated.2. Under resting conditions in preparations in dogs fasted for 24 h, the mean rate of pancreatic secretion was 16.4 μ1/min (s. e. m. = 2, n= 12). The mean concentrations of protein, bicarbonate and chloride in the pancreatic juice were 53.8 mg/ml (s. e. m. = 4.5), 18.0 mmol/1 (s. e. m. = 1.1) and 122.5 mmol/1 (s. e. m. = 7.5), respectively. Infusion of EGTA had no effect on resting secretion.3. Secretion elicited by dopamine or secretin was diminished about 50% during the intra-arterial infusion of EGTA (10−2 mM/ml) in the perfusing blood. The protein concentration in the secretion was diminished to a similar extent. The concentrations of bicarbonate and chloride in the pancreatic juice was not modified by EGTA infusion.4. Concomitant infusion of an equimolar concentration of CaCl2 solution abolished the inhibitory effects of EGTA infusion on the secretory responses to dopamine or secretin.5. The results suggest that dopamine and secretin influence the exocrine secretions of the pancreas by actions on both acinar and ductular cells. Acinar cell secretion is more susceptible to depletion of serum calcium levels than is secretion from ductular cells.
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