Uptake and release of choline in cultures of human glioma cells.
Human glioma cells (138MG) have a low-affinity uptake system for choline (Km = 20 microM; Vmax = 56 pmol/min/10(6) cells). The uptake is reduced by acetylcholine, hemicholinium-3, HgCl2, and phosphodiesterase inhibitors. Release of [3H]choline from preloaded cultures showed two pools with half-lives of 1.3 and 160 min. Choline release was stimulated by 8-bromo-cAMP or isobutylmethylxanthine. The results suggest that release of choline occurs by a facilitated diffusion transport system and is increased by elevations of intracellular cAMP.
D002460:Cell Line; D002794:Choline / Q000493:pharmacokinetics*; D005910:Glioma; D006801:Humans; D014407:Tumor Cells, Cultured / Q000378:metabolism*
D002794:Choline