Uenishi K, et al. - This inquiry was set up to study the impacts of vitamin D3 compounds on intestinal fractional calcium absorption (FCA) and calcium-regulating hormones in post-menopausal osteoporosis. As suggested in this work, FCA was stimulated by oral administration of vitamin D3 analogues [1α hydroxyl calcidiol (ALF) and eldecalcitol (ELD)] but not by plain vitamin D3. Notably, data indicated that ALF and ELD may directly stimulate intestinal vitamin D receptors as the reported impacts of vitamin D3 compounds on FCA were found to be independent of serum calcitriol concentration.