Effect of long term androgen removal on androgen-induced proliferation of seminal vesicle cells in adult mice

Male mice were castrated on day 60 after birth; daily injections of testosterone propionate (TP, 4 micrograms/g b.wt) were started 1.2 or 6 months after the castration. The incorporation of 5-[125I]iodo-2'-deoxyuridine [( 125I]IdUrd) into the whole seminal vesicles was determined on various days after starting the TP injections as an index for proliferation. Although the peak of [125I]IdUrd uptake was observed 3 days after starting the TP injections in both short (1-2 months) and long (6 months) term castrated mice, the peak was significantly lower and the period of proliferation was longer in the long term group than in the short term group; the weights of seminal vesicles before TP injections were 6 and 10 mg in the long and short term groups, respectively. Although TP injections induced the proliferation of only epithelial cells in the short term group, the same treatment induced the proliferation of both epithelial and fibromuscular cells in the long term group. The deficient responsiveness to androgen of the seminal vesicle cells found in the long term castrated mice was completely recovered by TP pretreatment for 2 weeks. The present findings suggest that so-called imprinted cells in the mouse seminal vesicle induced by neonatal and prepubertal testicular androgens are very slowly lost at least in part by androgen removal for long periods such as more than 6 months in adult mice and that the loss is at least in part due to the death of fibromuscular cells, which is recovered rather quickly by androgen pretreatment.