Antirachitic Properties of A.T. 10 for the Rat and Chicken

Abstract

A.T. 10 has an antirachitic potency of 30,000 I.U. per gram as assayed by the U.S.P. XI rat technique. A minimum protective level of A.T. 10 against rickets for chicks is around 6 I.U. of antirachitic activity per 100 gm. of ration. A toxic level is apparently about five times this dose. By weight comparison A.T. 10 is approximately one-eighth as potent an antirachitic for chicks as vitamin D₂. However, on a rat unit basis, A.T. 10 is nearly 200 times more effective than vitamin D₂. Rat unit for rat unit, A.T. 10 is about four times more powerful an antirachitic on the chick than vitamin D from cod liver oil. This is the first time an antirachitic substance of supposedly vegetable origin has demonstrated in chickens anywhere near the rickets preventive ability of vitamin D from cod liver oil when compared on a rat unit basis. Under the conditions of these experiments the action of A.T. 10 resembles that of vitamin D rather than parathyroid hormone.