Cloned mouse mast cells and normal mouse peritoneal mast cells. Determination of serotonin content and ability to synthesize serotonin in vitro.

We determined the serotonin (5-hydroxytryptamine, 5HT) content of growth factor dependent mouse mast cell lines or clones, and measured their ability to synthesize and store 3H-5HT from exogenous 5-hydroxy-[G-3H]-tryptophan (3H-5HTP) in vitro. Mast cells grown in vitro synthesized 3H-5HT from 3H-5HTP at rates equal to or greater than those of peritoneal mast cells freshly isolated from normal mice. Furthermore, under usual conditions of culture, mast cell lines or clones contained more 5HT than freshly isolated peritoneal mast cells.