The vitamin A effects on cell proliferation, differentiation and functioning might be due to its influence on genome expression at the level of regulation of the transcription of certain genes, posttranscriptional modification of mRNA levels, or changes in the membrane structural-functional organization. Vitamin A can affect the biosynthesis of various proteins, including those involved in regulation of development and cell functioning or determining cell sensitivity to hormones and hormone-like factors. Vitamin A can also influence the formation of secretory proteins which play the role of hormones. It is proposed to use the differential sensitivity of various cells in cell populations to vitamin A or its forms for studying intercellular relations. In particular, the capacity of retinol and retinoic acid to maintain the development and functioning of various vitamin A-dependent cells of the testis can be used for studying local regulation of spermatogenesis in mammals.