REVERSIBLE INHIBITION OF GROWTH OF B16 MELANOMA-CELLS BY DECREASED AMINO-ACID NUTRITION

The effect of limited amino acid nutrition upon the growth of B16 mela noma cells was investigated. It was observed that the cells in Basal M edium Eagle do not proliferate and are inhibited predominantly in the G1 phase of cell cycle. The cells which were inhibited in growth for 7 or 12 days in Basal Medium Eagle were able to commence proliferation when transferred to Eagle's Minimal Essential Medium containing higher concentration of amino acids. The proliferating cells were found to b e more evenly distributed throughout all phases of the cell cycle. The reversible inhibition of growth of B16 melanoma cells was caused by d ecreased concentrations of amino acids and not by their depletion in t he culture medium. The B16 melanoma cells which are known to be capabl e of highly autonomous growth in the absence of extracellular hormones and growth factors have appeared to be sensitive to nutritional inade quacy.