Abstract
We have employed 24 animals, 29 to 55 days of age, that were transferred from our stock diet No. 2 1 to vitamin A deficient rations. The experimental basal ration used in this work had the following composition: Casein (hot-alcohol extracted) 20; Northwestern yeast 10; salts No. 185, 2 4; lard 2; dextrin 64, irradiated for 30 minutes to insure an adequacy of vitamin D. In a number of experiments the lard in the ration was replaced by 1 to 2% of butter fat, in order to prolong the experimental period, so that the animals would be suffering from an insufficiency of vitamin A rather than from complete depletion of this dietary factor. This was done to prevent sudden death from pneumonia which occurs when all traces of vitamin A are removed from purified diets. The period of experimentation ranged from 80 to 150 days.
The methods used for the determination of blood constituents have been reported in previous publications. 3 , 4 The same technique was employed in our studies of vitamins D and G deficiencies, the results of which follow in the subsequent articles. In this study, as well as in those that follow, daily records were kept of food and water intake in the case of all animals, and the blood sugars were determined twice weekly. In addition, determinations of specific gravity were made at each bleeding, in order to obtain information on blood concentration.
Our results show that in various stages of vitamin A deficiency characterized by the severity of eye lesions, there are no significant changes in the concentration of true blood sugar. The figures approximate those found in animals on satisfactory diets. 3 In a good many instances the concentration of apparent sugar is considerably higher in the pathological animals than in the controls.
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