Aspirin inhibition of hypercalcemic effect of 1 alpha-hydroxyvitamin D3 in rats

Interaction of calcium regulating hormone, active form of vitamin D3, and aspirin (ASA) was studied in rats. One alpha-hydroxyvitamin D3 (1 alpha-OH-D3) produced a hypercalcemia in parathyroidectomized, thyroparathyroidectomized and thyroparathyroidectomized nephrectomized rats. The effect of 1 alpha-OH-D3 was inhibited by treatment with 200, 50 and 20 mg/kg p.o. of ASA. ASA did not stimulate the gut absorption of calcium in vitamin D deficient rats. These data suggest that ASA acts by inhibiting 1 alpha OH-D3 induced bone resorption. This is the first report demonstrating the inhibitory effect of ASA on bone resorption as induced by 1 alpha-OH-D3, although partial inhibition of bone resorption in vitro has been reported.