Effect of verapamil on bone resorption and formation in uremic rats.

It has been shown in vitro that verapamil inhibits parathyroid hormone-induced bone resorption. To determine the effect of verapamil administration on bone histology in rats with chronic renal failure, male Wistar rats were divided into three groups: subtotally nephrectomized (SNX), SNX treated with verapamil, 8 mg/kg/day p.o. (SNX-V) and control (C). Thirteen weeks later, the mandibular condyle bone was studied by histomorphometry. When compared to C rats, SNX rats had active bone disease, with increased resorption parameters (resorption surface, active resorption surface, osteoclast number) and accelerated mineral appositional rate. These parameters improved with verapamil administration. When compared to C rats, SNX-V rats had decreased osteoid seam width and mineral appositional rate. Serum parathyroid hormone was similarly elevated in both uremic groups. These data suggest that verapamil administration improves active bone disease in rats with chronic renal failure and decreases bone formation.