Immunohistochemical Localization of the Androgen Receptor in Rat and Human Tissues*

Immunohistochemical localization of the androgen receptor (AR) was performed in reproductive tissues, submaxillary gland, pituitary, and brain of the rat and in human prostate. AR was visualized using either of two polyclonal antibodies raised against peptides with sequences derived from rat and human AR. Tissue sections of 6-8 microns, frozen in isopentane and fixed in paraformaldehyde, were stained using immunoglobulin G fractions of immune, preimmune, and peptide-adsorbed immune sera in the avidin-biotin peroxidase procedure. AR was prominent in nuclei of acinar epithelial cells of epididymis, ventral prostate, seminal vesicle, and ductus deferens from the intact rat. Androgen withdrawal, 3 days after castration, resulted in the loss of receptor immunostaining, which was restored within 15 min of androgen administration. Stromal cell staining was absent or weak in the ventral prostate of intact rats, but was more evident in the epididymis. AR was confined to nuclei of cells within and bordering the interstitial compartment of the testis, including Sertoli cells, peritubular myoid cells, and interstitial cells, and was undetectable in germ cells. Submaxillary gland epithelial cells and a population of rat anterior pituitary cells showed strong nuclear staining of AR. In rat brain, AR was present in the medial preoptic, arcurate, and ventromedial nuclei of the hypothalamus, the medial nucleus of the amygdala, the CA-1 hippocampus, and the cortex. AR was prominent in acinar epithelial cells in human benign prostatic hyperplasia and was also present in stroma of fibromuscular benign hyperplasia. Heterogeneous staining was observed in stromal and epithelial cells of prostatic adenocarcinoma. The results of these studies indicate that AR can be detected immunohistochemically in a variety of tissues and cell types using antipeptide polyclonal antibodies. The presence of AR in tissues correlated with their known androgen responsiveness.