Studies of the mechanism of growth promotion of lymphoma cells by 2-mercaptoethanol in vitro.

Rates of incorporation of thymidine and uridine, but not leucine, decrease markedly in L1210 (V) cells within 1 hour of incubation in DULBECCO'S medium containing 10% serum. 2-Mercaptoethanol (2-ME) after a latent period of more than 5 hours causes an increase in nucleotide incorporation. Bovine serum albumin can substitute for serum in the medium, but a higher concentration of 2-ME is required for growth. After charcoal treatment of the albumin less 2-ME is required. These experiments suggest that inhibition of the tumor cells is caused by a serum factor whose effect is antagonized by the thiol.