THE METABOLISM OF ANIMAL TISSUES CULTIVATED IN VITRO: III. AMINO ACID METABOLISM OF STRAIN L CELLS IN COMPLETELY SYNTHETIC MEDIA

Abstract

Strain L cells, of mouse fibroblastic origin, have been cultivated in vitro in completely synthetic medium M 150 and in various modifications of this medium. The amino acid changes in the nutrient medium during cell cultivation have been studied by paper chromatography. A characteristic pattern of amino acid uptake and accumulation in the medium has been found. No change in the alanine concentration was observed but omission of alanine from the culture medium resulted in its accumulation in appreciable amounts. Omission of glutamic acid did not alter the pattern of amino acid changes by the cells. Omission of glutamine increased the uptake of amino acids and prevented amino acid accumulation. Omission of both glutamic acid and glutamine resulted in a virtual cessation of amino acid changes in the culture medium. Strain L cells decreased the adenine content of the medium and produced small amounts of hypoxanthine. These changes were not affected by alterations in the amino acid content of the medium. Omission of glutamic acid and glutamine from the culture medium did not cause an appreciable decrease in cell population or apparent degeneration of the cultures over a 30-day period.