Studies of Incurable Rickets. I. Respective Role of the Local Factor and Vitamin D in Healing

Abstract

The substitution of strontium for calcium in the rickets-producing diet produces a form of rickets which fails to respond to the very large amounts of vitamin D. The endochondral cartilage of strontium-fed animals both treated and untreated fails to calcify when incubated in artificial serum solution even with a Ca X P product of 60 which produces marked calcification in the endochondral cartilage of control rachitic rats. These observations strongly suggest an injurious effect of strontium upon the “local factor” in the hypertrophic cartilage of the provisional zone of calcification which brings about calcification at this area when conditions in the serum are favorable. The ability of vitamin D to cause an increase of the Ca X P even when healing does not take place, implies that this raising of the product is the function of the antirachitic vitamin in the cure of rickets.