Immunocytochemical demonstration of insulin or insulin-like immunoreactivity in the rat prostate gland

The indirect immunocytochemical technique was used in conjunction with anti-insulin antisera to localize insulin-like immunoreactivity in tissue sections and primary cell cultures from rat prostate gland. Positive immunostaining for insulin-like reactivity was demonstrated in the epithelium of the prostate gland. There appeared to be some variation in the intensity and localization of the immunoreactivity within different regions of the gland. Prostatic epithelial cells grown in culture in an insulin-free medium displayed strong cytoplasmic immunostaining when treated with anti-insulin antisera, while nuclear staining was absent. These results demonstrate that insulin-like immunoreactivity is present in the epithelium of the prostate gland and suggest that there may be some local insulin or insulin-like synthesis in this organ.