Amino acid transport by a muscle cell line.

An established rat muscle cell culture, L-6, was employed for the evaluation of muscle amino acid transport. The initial influx of 16 radiolabeled amino acids into these cells was determined, and an overall uptake profile was constructed. L-6 cells accumulate amino acids progressively with time by saturable, temperature-dependent processes. As found in other preparations, several amino acids have sodium-dependent uptake systems. There is a wide range in the rate of transport of the different amino acids. The overall profile of uptake is fairly reproducible and may be characteristic of muscle tissue; it does not resemble that previously found in other cell types. The profile of amino acid uptake into these cells compares favorably with the pattern of amino acid transfer from the bloodstream to muscle found in intact rats. It is concluded that muscle cell transport is basically similar to that of other cell types. L-6 muscle cells have an amino acid uptake profile which resembles that of intact muscle; they should thus prove useful in the further delineation of muscle amino acid transport mechanisms.