The effect of testosterone on cell renewal and mitotic cycles in sex accessory glands of castrated mice.

Abstract

ABSTRACT The effect of testosterone propionate on cell renewal rate and mitotic cycle of castrated mice was investigated. 0.25 mg of the hormone was given thrice at 24 h intervals and 50 μc of 3H-thymidine was injected simultaneously with the last hormone injection. After this the mice were killed at 1 to 2 h intervals. Ventral prostates and seminal vesicles were weighed and the thymidine incorporation into their epithelia determined in radioautograms. A piece of proximal small intestine was used as reference tissue. The labelling index in the castrated control animals was 1.3 for the seminal vesicle; 68 h after testosterone treatment it was 44. The figures for the ventral prostate were 1.9 and 37, and for the small intestine 44 and 57. The mitotic index in the prostate of the experimental animals and that in the intestine of all the animals was 0.5; in the seminal vesicle it was 0.4. The mitotic index in the accessory glands of the control mice was very low. The specific activity of DNA per nucleus was higher in the hormone treated than in the control animals. The cell cycle (TC) in the prostate was shortened from about 900 h to 20 h after testosterone. The synthetic phase (TS) was shortened from 16 to 7 h, presynthetic (TG1) phase from 900 to 10 h, whereas the postsynthetic phase (TG2) remained unchanged. The corresponding figures for the seminal vesicle were: TG2 from 4.5 to 0.5 h, TS from 12 to 7 h, TG1 from 900 to 10 h and TC from 900 to 18 h. The changes in the intestinal epithelium were less marked: TC from 22 to 16 h, TS from 8.5 to 8 h, TG1 from 12 to 6 h, while TG2 remained unchanged.