Effect of alpha-FMH and DPPE on colony-forming properties of human peripheral progenitor cells

Endogenous histamine regulates the haematopoiesis. Histidine decarboxylase inhibitor decreases the histamine level, and its intracellular antagonist decreases the histamine effect. The effect of histidine decarboxylase inhibitor (alpha-fluoromethyl histidine) and the intracellular antagonist of histamine [N'N-diethyl-2-4-(phenylmethyl) phenoxyethan-amine-HCl] was investigated on the colony-forming ability of human peripheral progenitor cells. Semi-solid culture medium was used both in the presence and in the absence of 3 U/ml erythropoietin. alpha-Fluoromethyl histidine was used in the range of 50 through 150 micro Mol/ml, the concentration of N'N-diethyl-2-4-(phenylmethyl) phenoxyethanamine-HCl was between 5 and 25 micro Mol/ml. The number of both the erythroide and the granulocyte macrophage colony was significantly decreased in a concentration dependent manner by the presence of both N'N-diethyl-2-4-(phenylmethyl) phenoxyethanamine-HCl (in all concentrations used) and &alpha-fluoromethyl histidine (at higher concentration). The inhibitory effect was decreased by erythropoietin.