Effect of bromocriptine on serum PTH, calcium and phosphate levels in azotemic rats

The dopamine agonist, bromocriptine, was studied with respect to its effects on PTH secretion and calcium homeostasis in Sprague-Dawley rats made azotemic by either total or subtotal nephrectomy. The oral or intraperitoneal administration of 0.25 mg of bromocriptine resulted in a significant increase in the serum calcium concentration when compared to animals given placebo. Bromocriptine produced no significant change in the BUN or the serum concentrations of creatinine, inorganic phosphate or PTH. The mechanism of the hypercalcemic effect of bromocriptine in azotemic rats is unknown. The hypercalcemia may, however, be due to stimulation of PTH secretion, since PTH levels in the serum were inappropriately high for the corresponding levels of calcium.