ANDROGEN REGULATION OF RNA POLYMERASE ACTIVITY IN ISOLATED MOUSE KIDNEY NUCLEI

1. 1. Isolated mouse kidney nuclei have RNA polymerase activity. The reaction is dependent on DNA, divalent cations (Mg2+, Mn2+) and the four ribonucleoside triphosphates. The amount of RNA obtained was decreased by the addition of actinomycin D, ribonuclease or deoxyribonuclease to the enzyme system. The addition of Mn2+ and (NH4)2SO4 greatly enhanced the activity. The optimum was 8.1 at the high and 8.8 at the low ionic concentration. 2. 2. Castration of adult male mice produced a sharp decrease in the RNA polymerase activity of the isolated nuclei of the kidney. Testosterone propionate reversed the effect of castration. The addition of Mn2+ and (NH4)2SO4 to the incubation system enhanced the enzyme activity but decreased the percent differences. The stimulating effect of the androgen was evident within 2 h after subcutaneous injection and was dose dependent. 3. 3. Adrenalectomy further decreased the RNA polymerase activity, which was not only restored but also increased by testosterone propionate to the same level as in non-adrenalectomized castrated mice. 4. 4. The suspension of the kidney nuclei in a solution of three of the nucleotides and the addition of the fourth nucleotide to the enzyme system in varying amounts resulted in a higher maximal polymerase activity for the castrated mice when CTP was varied and a lower value with GTP. Thus, the effects of castration and androgen were much less with the former and greater with the latter nucleotide. 5. 5. The incorporation of all the nucleotides in RNA was decreased by castration and restored to normal by testosterone propionate. The base composition of the newly synthesized RNA was not markedly changed. The A+U G+C ratio was approx. 0.50 for the three groups. The androgen caused a slight increase in the ratio. The addition of Micrococcus lysodeikticus RNA polymerase to the enzyme system did not produce any significant changes. The addition of (NH4)2SO4 produced an increase in the incorporation of the nucleotides and an increase in the A+U G+C ratio to approx. 1.0. © 1969.