Postnatal development of the prostate.

Postnatal development of the human prostate proceeds in the phases: (i) a regression period after birth, (ii) a quiescent period up to 12-14 years, and (iii) a maturation period between 14 and 18 years. During postnatal development no lobe formation is observed, but rather a differentiation gradient within the epithelial ducts. Morphogenesis and differentiation of the epithelial cords starts in an intermediate portion of the epithelial anlage and proceeds to the urethral and subcapsular portions. The latter is reached by about 17-18 years. Epithelial anlagen initially consist of a multilayered squamous or cuboidal epithelium which is transformed into a pseudostratified epithelium consisting of secretory, basal, neuroendocrine and mucous cells. The latter are lost during maturation. Secretion starts in adluminal cells (on day 12 in rat) which represent the major compartment of dividing cells. Onset for the expression of different secretory proteins (acid phosphatase, prostate specific antigen, beta-microseminoprotein) is identical in the individual secretory cell of the human prostate. Immature glandular outpocketings display a positive immunoreaction for basic fibroblast growth factor (bFGF) in the epithelium. Since no sign of leakage into the stroma is visible, the action of bFGF during epithelial/stromal interaction remains to be established.