The Effect of Ethyl Alcohol on Nitrogen Excretion in the Rat **

In the course of investigating the effects of alcoholt on the liver of the rat it was found that alcohol increased the choline requirement, an effect that was independent of changes in food consumption or caloric intake.1" To explore the possibility that alcohol induced a relative deficiency of choline by altering some aspect of protein metabolism, an investigation of the effects of alcohol on nitrogen balance was undertaken, the results of which are the subject of this report. Although the rat has been used extensively to investigate the metabolism and nutritional value of alcohol, surprisingly few studies in this species have dealt with the problem of the effects of alcohol on nitrogen metabolism. Mitchell? observed that rats maintained on a liberal milk diet and given supplements of alcohol for a period of 42 days had a significantly higher carcass content of nitrogen than pair-fed unsupplemented controls. From this he concluded that the energy of alcohol is to a large extent available "for physiological purposes" and, thus, promotes growth and nitrogen retention. Although alcohol appeared to facilitate the digestion and absorption of dietary protein in these experiments, since it reduced losses of nitrogen in the feces, the calculated amount of nitrogen thus gained constituted only a small fraction of the extra nitrogen recovered in the carcass, so that it must be assumed that alcohol also reduced losses of nitrogen in the urine. In a more acute experiment, Shapiro' found that in rats subjected to fasting, the administration of alcohol for a period of four days failed to spare nitrogen and, indeed, in half the animals increased nitrogen losses in the urine. Similarly variable results have been reported in the dog. In short-term experiments, Munk' found that small amounts of alcohol spared nitrogen while large amounts increased urinary nitrogen excretion. These observa-