Effect of growth hormone on urine calcium and serum vitamin D metabolites in renal failure.

Growth hormone (GH) causes a modest increase in urine calcium excretion in normal adults, but uremic rats given both GH and calcitriol developed hypercalciuria. Ten short prepubertal children with renal insufficiency treated with recombinant human GH (rhGH) had urine calcium to creatinine (Ca/Cr) ratios and serum vitamin D metabolite concentrations monitored prospectively for up to 24 months. Six were also treated with calcitriol and two with other vitamin D preparations. Mean urine Ca/Cr ratios or mean serum concentrations of 1,25-dihydroxy vitamin D, 24,25-dihydroxy vitamin D, and 25-hydroxy vitamin D did not change significantly during treatment with rhGH. The risk for rhGH-induced hypercalciuria is small in children with renal insufficiency, even when treated concomitantly with a vitamin D preparation.