Inhibition of prostate ductal morphogenesis by retinoic acid

Purpose: To examine the effect of retinoic acid on prostate ductal morphogenesis. Materials and Methods: Newborn male Balb/C mice were injected with 25 mg./kg. all-trans retinoic acid or vehicle alone. Animals were sacrificed at 60 days of age and prostate ductal morphology was quantitatively assessed by microdissection. Total prostate DNA was quantitated by DPA assay. Results: The greatest effect was seen in the ventral prostate. Retinoic acid treated animals showed a 20% decrease in mean number of branch-points (p = 0.0006) with a corresponding 13% decrease in duct tips (p = 0.026). The combined ventral and dorsal prostate showed an effect with a 12% decrease in ductal branchpoints (p = 0.048). There was no effect on animal or organ weight and no effect on DNA content within the prostate. There was no difference in the prostate histology of treated and control animals. Conclusion: Retinoic acid administration in the newborn period inhibits mouse prostate ductal morphogenesis. This effect appears independent of an inhibition of overall growth.