Inhibitory effect of calcitonin on pure human pancreatic secretion.

The inhibitory effect of calcitonin on human pancreatic secretion was evaluated to examine whether the different results reported earlier between humans, cats and dogs can be ascribed to the different sensitivity of these species to calcitonin, as suggested by some investigators. Pancreatic juice was obtained by endoscopic cannulation of the pancreatic duct from 11 patients with relapsing pancreatitis during intravenous infusion of secretin (1 U/kg/h) plus caerulein (0.04 microgram/kg/h). After steady secretion was attained 20 min after the beginning of collection, five 2-min fractions were obtained before, and ten 2-min fractions were obtained after intravenous infusion of calcitonin (1 IU/kg/h). The pre- and post-calcitonin fractions from each patient were compared by Student's t-test. Calcitonin inhibited the secretory volume (26.8 to 65.6%) and bicarbonate secretion (21.4 to 62.0%) in 8 patients, and amylase (48.4 to 89.5%) and lipase secretion (47.4 to 90.5%) in all patients. The present studies reconfirmed that prominent inhibition of enzyme secretion occurs in humans. A new finding was that significant inhibition of the secretory volume and bicarbonate secretion occurs in humans. The inhibitory effects of calcitonin in humans did not appear to differ from those in cats and dogs, when evaluated similarly with the use of pure pancreatic juice.