Evidence for the Promotion of Bone Mineralization by 1α,25-Dihydroxycholecalciferol in the Rat Unrelated to the Correction of Deficiencies in Serum Calcium and Phosphorus

摘要: Concurrent administration of 1alpha,25-dihydroxycholecalciferol [1alpha,25-(OH)2-CC] to intact and thyroparathyroidectomized rats treated with ethane-1-hydroxy-1,1-diphosphonate (EHDP) prevented or reversed the EHDP-induced inhibition bone mineralization as measured by changes in epiphyseal plate width ash content bone. An analog, 1alpha-droxycholecalciferol, was also effective. Recovery after EHDP treatment significantly improved 1alpha,25-(OH)2-CC evidenced enhanced uptake 45Ca plates decreased widths. Cholecalciferol (CC), ergocalciferol, dihydrotachysterol2, 5,6-trans-CC, 25-OH-CC, 5,6-Trans-25-OH-CC, 1alpha24R,25-(OH)3-CC blocked widening, but required high, pharmacological dose levels. 24R,25- (OH)2-CC inactive at doses up 10 microgram/day. Since EHDP-treated are not deficient calcium phosphate, these data suggest that promoted independently effects upon intestinal absorption phosphate.