[Histological and cell kinetic studies of the growth of rat prostate of various ages].

Histologic and cell-kinetic investigations were performed on the developing prostate of growing rats. The ages ranged from 1 day to 15 months. The most intensive cell proliferation is observed within the first 2 weeks after birth. Thereafter, the cell proliferation decreases continually as the cellular differentiation of the prostatic glandular epithelium increases to form well-differentiated secretory cells. The second peak of cell proliferation occurs with the beginning of sexual maturation and an elevated testosterone production. But the rapid increase of prostatic weight at that time is mainly caused by an increased formation of secretory and interstitial tissue fluids. The different lobes of the adult prostate all exhibit the same cellular proliferation pattern. The prostate belongs to the organs with stable growth pattern and an only small cellular turnover. Mitotic figures are extremely rare under normal conditions. But this low cellular proliferative activity may be easily changed, in contrast to other organs with stable tissue and steady-state growth, i.e., liver and kidney, in dependence of hormone levels.