Studies in vitamin A. 23. Vitamin A and its occurrence in Amblystoma tigrinum

Abstract

The proportions of vit. A1 and A2 in an animal which can exist both as sexually mature aquatic larvae and as terrestrial adults were investigated. The vit. A and carotenoid contents of the livers of A. tigrinum on various diets were detd. No conversion of beta-carotene to vit. A could be observed. Unless preformed vit. A had been added to the diet, no vit. A could be detected in the livers. The requirements of this species for vit. A must be either extremely small, or non-existent, or, alternatively, that an unrecognized compound other than vit. A1 is present and can replace the vit. in physiological processes.