Studies in the metabolism of tissues growing in vitro

PREVIOUS work has shown that by using the tissue culture technique the production of ammonia and urea by growing and non-growing cultures can be estimated. By comparison with controls it has been found that the growing cultures produce considerable amounts of these substances whereas the non- growing ones do not [Holmes and Watchorn, 1927], and that the presence of glucose, while favouring the growth of the tissue, inhibits the production of ammonia and urea during this growth [Watchorn and Holmes, 1927]. It seemed that it might be of interest to compare the effect of other sugars with that of glucose, in order to determine whether the utilisation of a carbohydrate necessarily has this "protein sparing" effect, or whether it depends upon the type of carbohydrate utilised and thus upon the method of breakdown.