Morphological study of the development of the disseminate prostate in intact and castrated male pigs aged two to six months.

The light-microscopical and ultrastructural differentiation of the disseminate prostate was studied in 12 boars and 8 barrows, ranging in age from 8 to 28 and 12 to 27 weeks, respectively. The barrows had been castrated at the age of 8 weeks. In young boars the prostate is organized in an inner zone and an outer zone. The glandular tubules of the latter are more differentiated than those in the inner zone. Sexual maturation in the prostate is characterized by almost complete reduction of the inner zone and concomitant enlargement of the outer zone. This differentiation of the inner zone occurs progressively and is manifested by a higher density of the glandular tubules, by a decrease in the number of basal cells and by an increase in the secretory tubular cells containing more microvilli, organelles and secretory vesicles. A few weeks after castration, the characteristic morphology of the undifferentiated inner zone is found throughout the entire glandular layer. The number of glandular tubules in barrows has decreased, and their cells show minimal secretory activity, nuclear indentations and a decrease in their organelles. A further castration effect is vacuolization of the perinuclear cytoplasm in numerous glandular cells.