The Ca2+-dependent protease inhibitor of rat ventral prostate: properties of the inhibitor and effects of castration on Ca2+-dependent protease and inhibitor activities

Effect of castration on metalloprotease activities in the lateral, dorsal, and anterior lobes of the rat prostate

Several proteolytic enzymes are involved in mediating the regression of the prostate gland following castration. A previous study showed that plasminogen activator activities are elevated only in the ventral lobe by castration in the rat. Since matrix metalloproteases represent a different class of protease that degrade extracellular matrix, this study examined their activities in the lateral, dorsal, and anterior lobes of the rat in response to androgen deprivation. The results indicate that, in contrast to plasminogen activators, metalloprotease activities are increased in the lateral, dorsal, and anterior lobes following orchiectomy. This suggests that differences in regulation of certain proteases by androgens may occur in individual prostatic lobes.

Immunocytochemical localization of cathepsin D in rat ventral prostate: evidence for castration-induced expression of cathepsin D in basal cells

Cathepsin D (EC3.4.23.5) is an aspartyl endopeptidase involved in lysosomal proteolysis. Its functional role is uncertain. This study was undertaken to determine the cellular and subcellular distribution of cathepsin D in the normal rat ventral prostate and its possible role in the castration-induced atrophy of the gland. Cathepsin D was localized immunohistochemically to perinuclear lysosomes in secretory cells, in capillary endothelial cells, and, occasionally, in stromal cells of the untreated animal. Castration resulted in an increased number of cathepsin D-positive cells in the stroma within 24 hr. By 48 hr after castration autophagolysosomes formed in secretory cells and apoptotic bodies appeared in the epithelium. Although apoptotic bodies generally contained immunoreactive cathepsin D, a subpopulation of larger apoptotic bodies, which commonly rested on the basement membrane and contained multiple inclusions, were more variable in cathepsin D expression. The induction of cathepsin D in dendritic cells basally oriented in the epithelium was noted at 4 days of castration. These cells had a phagocytic phenotype, were distributed periodically along the basement membrane, and were not found in ductal epithelia. Treatment with actinomycin D or hydrocortisone to reduce the rate of regression of the ventral prostate blocked the appearance of these cathepsin D-positive, basally oriented epithelial cells. Our data indicate that this cathepsin D-positive, phagocytic cell differentiates from a cell resident in the prostatic epithelium. We suggest that it differentiates from basal cells in the secretory tubuloalveolar portion of the gland and that it is involved in the destruction of regressed secretory cells.