Synergistic Effects of 1,25(OH)₂D₃ and 1,24,25(OH)₃D₃ in Rachitic Chicken and Rats

Abstract

The malabsorption of calcium found in many postmenopausal osteoporotic patients has been connected with a disturbance in vitamin D metabolism, although the l,25(OH)₂D₃ concentrations in serum are often not much different from normal subjects. A number of studies in which l,25(OH)₂D₃ or lα(OH)D₃ was given to osteoporotic women claimed beneficial effects (Gallagher et al. 1982), while others concluded that l,25(OH)₂D₃ is of no use in the treatment of the majority of postmenopausal osteoporotic women (Christiansen and Rodbro 1984). Pharmacological doses of l,25(OH)₂D₃ did not improve the intestinal calcium absorption and are not alternative to estrogens as prophylactic treatment of postmenopausal bone loss (Riis et al. 1985). The findings of various investigators are, however, not consistent.