[Effect of cyclic nucleotides and hormones of homologous methylation in nuclear homogenates of rat bone marrow].

In vitro and in vivo studies showed that methylation of homologous DNA in nuclear homogenates of rat bone marrow is controlled by cyclic nucleotides and some hormones. The cyclic nucleotides and their dibutyryl analogs inhibited homologous methylation of DNA in the presence and absence of phosphodiesterase inhibitors. In the presence of Ca2+ the inhibiting effect of the nucleotides was more pronounced. Prostaglandins inhibited DNA methylation in a weaker degree while insulin and erythropoietin had a stronger effect in comparison with the nucleotides. Histamine stimulated DNA methylation, whereas acute hypoxic hypoxia caused a reduction in the rate of DNA methylation.