To determine changes in parathyroid hormone secretion and target organ response caused by acute pancreatitis before the development of systemic toxic conditions, experimental acute pancreatitis was induced in rats with a choline-deficient, ethionine-supplemented diet. After 7 days, the rats were weighed and bled, and one kidney was assayed for 25-hydroxyvitamin D1 hydroxylase activity. Several manifestations of pancreatitis were observed in rats given the diet: weight loss (from 29.6 to 26.3 g vs that for control rats, from 29 to 52.8 g) and lower dietary intake (15.5 vs 47 g per rat per 7 days). Serum amylase levels fell from 1794 to 350 U/L in rats given the choline-deficient, ethionine-supplemented diet compared with levels of 1800 to 2100 U/L in control rats. The pancreases of rats given the choline-deficient, ethionine-supplemented diet showed degeneration, necrosis, and hemorrhaging. Serum levels of calcium, phosphorus, chloride, and parathyroid hormone did not change significantly throughout the experiment. Renal 25-hydroxyvitamin D1 hydroxylase activity was higher than in control rats (8.9 +/- 0.8 vs 7.6 +/- 0.6 fmol/mg of kidney per minute). Acute pancreatitis in this experimental animal model does not alter serum levels of calcium and parathyroid hormone or reduce target organ responsiveness to the hormone.