A flow cytometric analysis of DNA synthesis and a quantitative investigation of nervous system-specific S-100 protein were performed on cultured rat glioma (C-6) cells in the course of morphological differentiation induced by 1 mM dibutyryl cyclic AMP (dbc-AMP). The flow cytometric analysis revealed that a marked suppression of DNA synthesis was caused by dbc-AMP. The content of S-100 protein in dbc-AMP treated cells began to increase on the fourth day after the treatment with a subsequent increase to approximately 10-fold over the control cells at the stationary phase. These results suggest that S-100 protein is a useful biochemical index for estimating the degree of differentiation of glioma cells.
micro-complement fixation assay