Vitamin D3 and absorption of calcium in the chick.

Although it has been known for many years that vitamin D is implicated in the metabolism of calcium, the exact biochemical mechanism of its action is still not clear. There have been reports that yeast (Braude, Kon & White, 1943), some grasses and other leafy vegetable matter (Ewer & Bartrum, 1948; Grant, 1951; Weits, 1952; Raoul, Marnay, Le Boulch, Prelot, Guerillot-Vinet, Bazier & Baron, 1957) and pig's liver (Coates & Harrison, 1957) have rachitogenic effects in certain species. It is difficult to study the mechanism on which these rachitogenic properties depend until the role of vitamin D in preventing rickets is better understood. For this reason the experiments reported here were undertaken.