The effects of androgen and estrogen on thymidine kinase and tissue plasminogen activator in the prostate of immature rats (author's transl)

Abstract

The effect of testosterone propionate (TP) or estradiol-17 beta (E2) on the activities of thymidine kinase (TK) and tissue plasminogen activator (Act) in the prostates of 22 day old immature SD rats was studied. The Tailor and fibrin plate methods were applied to measure the activities of TK and Act respectively. Act activity was expressed in terms of the Urokinase International Unit. After a single TP injection im, TK activity began to increase at 24 h and peaked at 48 h followed by a rapid decrease. The maximum activity, 40.0 +/- 11.5 pmol/mg protein/15 min, was 50 times higher at 48 h and peaked at 96 h, with a subsequent decline to the control value within 14 days. The maximum Act activity, 5.1 +/- 0.4 U/prostate, was 1.6 times the control value. The activities of both TK and Act altered depending on TP doses, 1 mg/100 g BW of TP brought about their maximum activities at 48 h and 96 h respectively. Three TK isozymes were obtained from the prostates by DEAE-cellulose column chromatography. Fraction A, which was eluted in O M NaCl, differed from other isozymes in that its activity was only slightly suppressed by dCTP and was elevated most conspicuously after TP injection. Elevated activities of both TK and Act after TP injection were completely inhibited by Puromycin or Actinomycin D. The results of the present experiment demonstrated that TK and Act were synthesized in the prostate cells after TP injection and were androgen dependent. E2 did not inhibit the elevation of TK and Act activities by TP injection. In the present study estrogen showed a synergetic effect with androgen on these two activities, especially TK, in the rat prostate.