Effect of gallium nitrate on tamoxifen induced hypercalcemia in rats bearing mammary tumor.

AIM To study the effect of gallium nitrate in the treatment of flare hypercalcemia in rats, bearing mammary tumor with bone metastasis. MATERIALS AND METHODS Female Sprague-Dawley albino rats were used in the study. Animals were divided into 5 groups: normal control; hypercalcemic rats bearing DMBA-induced mammary tumors; flare hypercalcemic animals bearing DMBA-induced mammary tumors (hypercalcemic rats, treated with tamoxifen at the dose of 10 mg/kg); flare hypercalcemic rat bearing DMBA-induced mammary tumors, treated with gallium nitrate at the dose of 2.5 mg/kg; control rats, treated with gallium nitrate at the dose of 2.5 mg/kg. Eligibility criteria - serum calcium levels were 11.0 mg% or above. Biochemical parameters were measured, using standard methods. Urinary excretion of calcium, creatinine ratio, urinary bone marker were also evaluated by using standard method. RESULTS All flare hypercalcemic rats were treated with gallium nitrate and developed normocalcemia. Biochemical parameters were measured in hypercalcemic and flare hypercalcemic animals. Calcium level in blood serum, alkaline phosphatase were significantly higher in flare hypercalcemia than in hypercalcemic rats. Urinary pyridinoline, deoxypyridinoline and hydroxyproline were also elevated in flare hypercalcemic rats. In contrast, intact parathyroid hormone and albumin levels were lowered in flare as well as hypercalcemic groups when compared with normal control groups. After gallium nitrate treatment all the above parameters returned to normal level. CONCLUSIONS Administration of gallium nitrate in vivo is highly effective in treatment of flare hypercalcemia.