Regulation of DNA methyltransferase in the testis of rat.

In mammalian DNA, the base 5-methylcytosine is generated by post-replicational methylation of cytosine residue by DNA methyltransferase. In this study the levels of DNA methyltransferase of testis during various ages and the effects of gonadotropic hormones on immature rat testis were studied. It was observed that the specific activity of DNA methyltransferase was high in the testis at the age of 20 and 30 days. After this age, the activity of DNA methyltransferase declined significantly and was maintained at lower level from days 120 to 240. Treatment with follicle stimulating hormone significantly decreased the enzyme activity in the testis while luteinizing hormone did not cause any effect. These results indicate that DNA methyltransferase of certain cells in the testis is under the influence of follicle stimulating hormone.