Influence of certain nutrients on changes in adipose and dental tissues of vitamin E-deficient rats.

It has been shown that certain symptoms in chicks, namely, exudative diathesis, yellow coloration of the adipose tissue, and encephalomalacia, and in rats, namely, yellowbrown coloration of the adipose tissue, and depigmentation of the incisors, depend upon the consumption of vitamin E-deficient diets rich in highly unsaturated fatty acids (Dam, 1944a, b ; Dam & Granados, 1945a, b ; Granados & Dam, 1945a, b; Granados, Mason & Dam, 1945, 1946). Formation of peroxides preceded, and in some instances paralleled, the brown coloration in the adipose tissue of these animals (Dam & Granados, 1945a, b) . The pigment responsible for the coloration of the adipose tissue was found to consist of at least two fractions: one of them is fat-soluble, and the other, which occurs in larger amounts, is not extracted by lipid solvents (Dam & Granados, 1945a). Histologically, the main pigment (fat-insoluble fraction) of the adipose tissue was found to be represented by an acid-fast pigment in the fat cells at different stages of development. The histopathological changes in the adipose and other tissues were studied to a certain extent (Dam & Mason, 1945; Mason, Dam & Granados, 1946; Granados et al. 1947). Moreover, a method for the histochemical demonstration of fat peroxides has been developed (Glavind, Granados, Hartmann & Dam, 1949), and applied to the study of the relationship between peroxides and the formation of the acid-fast pigment in the adipose tissue of vitamin E-deficient rats (Granados, Glavind, Hartmann & Dam, 1950). Furthermore, since depigmentation of the incisors is a symptom important in the investigation of the metabolic role of vitamin E, a method for evaluating the degree of depigmentation of the enamel in vitamin E-deficient rats was developed (Granados &