Blood Uric Acid and Liver Uricase of Zinc- Deficient Rats on Various Diets*

The necessity of zinc in rat nutrition was first shown conclusively by Todd, Elvehjem, and Hart (1). In this and in subsequent work a high carbohydrate, zinc-low ration has been used. The possibility exists that the zinc requirement of the rat may be influenced by rations in which fat or protein furnishes the chief source of calories. A physiological relationship between zinc and vitamin B1 has been suggested by certain reports in the literature. Lohmann and Kossel (2) have shown that zinc ions activate the enzymatic decarboxylation of pyruvic acid when a yeast maceration juice is t,he source of the protein portion of the carboxylase system. Eggleton (3) found a 50 per cent decrease in the zinc content of skin, hair, and nails of persons suffering from beriberi. Both Eggleton (3) and Morris (4) have noted a correlation between the zinc and vitamin B1 content of foods. Since bot,h zinc and vitamin B1 are required by the rat on the usual high carbohydrate diet, it is possible that any interdependence which may exist between these two nutrients can be demonstrated by placing rats on a high fat, zinc-low diet. If such a diet has a zinc-sparing action as well as its known vitamin Bl-sparing action, an interdependence between these two substances may be indicated. If there is no zinc-sparing action of the high fat diet, it can be con-