The application of immunoperoxidase methodology for the visualization of prolactin binding sites in human prostate tissue.

In previous studies the immunoperoxidase method was used to detect intracellular prolactin binding sites in epithelial cells of normal and neoplastic rat prostate. As an extension of this work, the same approach was used to test for and to localize prolactin binding sites in autopsy and biopsy specimens of formalin fixed, paraffin embedded human prostate. Rehydrated tissue sections were exposed to varying concentrations of human placental lactogen or human prolactin and then to human placental lactogen or human prolactin antisera. The loci of hormone binding were visualized by an immunoperoxidase staining sequence. Hormone pretreatment produced immunospecific, dose related staining inside epithelial cells of normal, hyperplastic, and neoplastic human prostate indicative of intracellular prolactin binding. The patterns of intracellular hormone binding in human prostate were similar to those seen previously in rat prostate tissue. The possible involvement of prolactin in prostatic cancer and the potential diagnostic value of the immunoperoxidase approach to hormone binding are discussed.