Morphogenesis of ductal networks in the mouse prostate.

Postnatal growth and development of the glandular architecture of the ventral and dorsolateral lobes of the mouse prostate (VP and DLP) were investigated by microdissection techniques that permitted precise quantification of the numbers of primary ducts emerging from the urethra, the terminal ductal tips, and ductal branch-points. At birth both the right and left lobe of the VP consisted of 1-3 main ducts that had already undergone secondary and tertiary branching. In contrast, at birth the more complex DLP had 9-12 unbranched main ducts per lobe on both the right and left sides. During the first 15 days after birth, 80.7% of tips and 76.4% of branch-points of the adult gland formed in the VP, and 70.4% of tips and 53.6% of the branch-points formed in the DLP. Ductal branching was completed by 60 to 90 days. The DLP developed in three stages: first, formation of unbranched main ducts (first 10 days); second, distal branching of each main duct resulting in 3-5 terminal branches per main duct (10-15 days after birth); third, elaboration of intraductal mucosal infolding in distal ducts after 30 days of age. Ducts of the lateral prostate (LP), a ventrolateral subdivision of the DLP, initiated branching morphogenesis between 1 to 5 days after birth. The LP grew into and became embedded within the capsule of the VP, which may explain why the ductal architecture of these two lobes are similar. These heretofore unrecognized differences in the organogenesis and morphology of the mouse VP and DLP and the striking morphological heterogeneity both between and within the lobes of the mouse prostate may be morphological manifestations of functional heterogeneities within the prostate.