Аннотация:The main coponents of chromatin (DNA and protamine-like proteins) were studied in the dihin- fnd NMU-treated mouse spermatogenic cells using quantitative cytochemistry. Marked variation of DNA content and deficiency of the basic nuclear proteins have been shown in epididymal spermatozoa developed from cells, which were at the moment of treatment either at the early prophase I or at intermediate stages of spermiogenesis. These stages are, respectivly, one of the genetically most sensitive stages and a stage of active syntesis of sperm-specific proteins, which play important role in condensation and stabilization of gamete chromatin. The combined ust of DNAse and Feulgen reaction allowed us to obtain new data about cytochemical properties of chromatin in the other types of mouse germ cells after treatment with chemical mutagens