The effect of rat liver carcinomas, growing in the yolk sacs of chick embryos, on the free glutamic acid and glutamine content of the eggs.

Observations in this laboratory have indicated that human subjects with malignant growths exhibit a significant elevation in plasma glutamic acid concentration (2, 5) . No such elevation was observed in subjects with benign growths, al though it has been shown that an elevated plasma glutamic acid level may be observed in clinical conditions other than malignancy (5). The results suggest that protein metabolism is abnormal in those patients with malignant growths. Informa tion with regard to the alteration in metabolism which causes the increase in plasma glutamic acid has not been available, but it seems likely that a failure in renal excretion is not responsible (6). Since a steady supply of chick embryos, with rat liver carcinomas growing in their yolk sacs, was available from the Department of Anatomy of this University and since these tumor-bearing fertile eggs made it possible to study glutamic acid in a closed system, it was decided to compare cer tam aspects of glutamic acid metabolism in tu mor-bearing to those in nontumor-bearing incu bated fertile eggs. A preliminary experiment mdi cated that an increase in free glutamic acid oc curred in such eggs during tumor growth and prompted the studies now described.