Regional Expression of Transforming Growth Factor-α in Rat Ventral Prostate during Postnatal Development, after Androgen Ablation, and after Androgen Replacement1

The prostate is a highly heterogeneous organ, composed of different types of epithelial and stromal cells organized regionally along the ductal network. Although androgen-stimulated growth and maintenance of the prostate gland primarily involve epithelial cells, it is unclear whether all epithelial cells are androgen dependent. Moreover, the actions of androgens may not be direct; a number of polypeptide growth factors, including transforming growth factor-α (TGFα), are postulated to mediate androgen action in the rat prostate. In this investigation, using an immunohistochemical technique, we examined the cellular and regional expression of TGFα in the rat ventral prostate during postnatal development to adulthood. TGFα-immunopositive cells were located throughout the ductal epithelium from postnatal days 5–20. By day 45 and thereafter, regional variation in TGFα expression became apparent; epithelial cells in the proximal segment exhibited intense staining, whereas those in the distal segment exhibited n...