TPO induces increased acetylcholinesterase content of L8057 cells. L8057 cells were grown in IMDM with 10% fetal calf serum alone (medium) or with supplemental TPO (4% conditioned medium) or with 50 nmol/L TPA. Acetylcholinesterase content was determined by fluorimetric assay; the graph indicates the mean of triplicate determinations and standard error of mean. These results are representative of five separate experiments.