Specific chalone inhibition of the regeneration of the JB-1 ascites tumour studied by flow microfluorometry

Abstract

The variation in the DNA distribution in the JB-1 and the Lla2 ascites tumour was investigated by means of flow microfluorometry (FMF) in the plateau stage and during the initiation of the regenerative growth induced by percutaneous aspiration. The study showed that a considerable influx of cells with G1DNA content into the S phase occurred in both tumours about 10 hr after aspiration. In the JB-1 tumour, these initial regenerative changes could be reversibly blocked by injections of cell-free plateau JB-1 ascitic fluid or an ultrafiltrate of this ascites. In contrast to these observations no delay in the regenerative changes was observed in the L1a2 tumour after treatment with JB-1 ascites or the ultrafiltrate. The study supports the assumption of a specific growth regulation of the JB-1 ascites tumour and emphasizes the suitability of FMF analyses in cell-kinetic studies in which short-term fluctuations take place in the distribution of cells with different DNA content.