Warburg and Hiepler1 have stated that ascites tumour cells show the highest metabolic rates when incubated in their own ascitic fluid. Littlefield and Keller2 later showed that the incorporation of 14C-amino-acids into mouse ascites cell proteins occurs at a rapid rate when the whole ascitic fluid is fortified with glucose and buffer salts and incubated in air. Incorporation is considerably greater than when buffer salts alone are used. More recently, Quastel, Bickis and Vas3 reported that the sera of many different species of animals (rat, mouse, rabbit, guinea pig, ox) stimulate the incorporation of 14C-glycine into the proteins of washed intact Ehrlich mouse ascites cells in vitro, in some cases by as much as fivefold. This stimulation of incorporation was also shown by the mouse ascitic fluid and by heated serum ultra-filtrates. The stimulation of incorporation of amino-acids into these cells by rat serum has now been investigated in greater detail and found to be due to the combined effects of glucose, glutamine, bicarbonate and amino-acids. These substances, used in the same concentrations as are found in the serum, can replace the serum fully (see Table 1).
About this article