Novel Inducers and Inhibitors of Differentiation of Friend Erythroleukemia Cells: Application of an Opal Glass Transmission Method to Study of Erythroid Differentiation: (erythroid differentiation/poly(ADP-ribose)/bile acids/opal glass method/Friend leukemia cells).

The potencies of poly(ADP-ribosylation)-inhibitors in inducing erythroid differentiation of Friend erythroleukemia cells were surveyed. Picolinamide and m-aminobenzamide were newly found to be inducers, whereas compounds related caffeine did not induce differentiation. In other series of experiments some bile acids suspected of being tumor promoters were found to inhibit the differentiation like typical tumor promoters such as phorbol esters. These modifications of erythroid differentiation were detected by an opal glass transmission method. This method is simpler than any previously reported methods, and is sufficiently reliable to use in determining hemoglobin in living cells as a quantitative marker of erythroid differentiation.