QUANTITATIVE ANALYSIS OF THE ESTERASES IN RAT MEGAKARYOCYTES BY A RADIO-ISOTOPE CYTOCHEMICAL TECHNIQUE

Megakaryocytes from bone marrow of immature rats have been treated with ³H-DFP, and the grain density over them measured in autoradiographs. The uptake of labeled DFP is reduced by one-third by eserine and by the AChase inhibitor 284C51, and by reactivation with pyridine-2-aldoxime. It is concluded that one-third of the DFP taken up by megakaryocytes represents binding to true AChase. The other esterases present include no significant amount of pseudocholinesterase.