Serum calcium metabolism in acute experimental pancreatitis.

Serum calcium changes in severe pancreatitis were studied in 23 dogs. Twelve dogs underwent duodenotomy and served as controls. Pancreatitis was induced in the other 11 by autologous bile injection (1 ml/kg) into the pancreatic duct. Serum amylase, total calcium, ionized calcium, albumin, magnesium, chloride, phosphorous, parathyroid hormone (PTH), and calcitonin were measured at 0, 1/2, 1, 3, 6, 24, 48, and 72 hours after duodenotomy or bile injection. Serum amylase levels became significantly elevated in all dogs with pancreatitis at 30 minutes (p less than 0.01) and remained so throughout the entire experiment. Total calcium levels dropped significantly 30 minutes after pancreatitis was induced from 10.0 +/- 0.3 mg/dl compared with 8.8 +/- 0.4 mg/dl in control dogs (p less than 0.05) and remained statistically lower for as long as 1 hour. Ionized calcium levels were significantly lower than were those of control dogs at 1/2, 1, 3, and 6 hours (p less than 0.05). Serum magnesium and chloride levels showed no significant changes between both groups. The only significant difference in phosphorus values was at 6 hours when they were higher in dogs with pancreatitis than in controls (6.2 +/- 0.3 mg/dl versus 4.8 +/- 0.4 mg/dl; p less than 0.05). Serum albumin levels remained unchanged throughout the study except for 48 hours when they were significantly lower in animals with pancreatitis (p less than 0.02). PTH levels were significantly greater in dogs with pancreatitis than in controls at 1, 3, 6, and 24 hours (p less than 0.05). There was no significant difference in calcitonin levels between both groups. Ionized calcium is a more reliable indicator of calcium fluxes in acute experimental pancreatitis since it remains depressed longer than total serum calcium. The time course of PTH elevation indicates a reaction to hypocalcemia, and failure of PTH secretion is not the cause of hypocalcemia in pancreatitis. This study does not support elevation of calcitonin as a cause of hypocalcemia in acute pancreatitis.