Lactate transport in cultured glial cells.

Uptake of L-lactate was investigated with a radioactive tracer method in cultured rat glioma cells and in astroglia-rich primary cultures derived from rat brain. In the glioma cells, a saturable component of uptake was identified with half-maximal uptake occurring at 1.0 +/- 0.4 mM lactate. In addition, a non-saturable component dominated the uptake at high concentrations of lactate. In astroglia-rich primary cultures, no saturable component of uptake could be detected in the concentration range studied (0.1-15 mM). In conclusion, lactate uptake at physiological concentrations is predominantly mediated in the glioma cells by a carrier-dependent process, whereas in astroglial cells, simple diffusion appears to be the dominant way of lactate transport.