The prostate of the gorilla.

The prostate gland from a 32-year-old gorilla was examined. The prostate weighed 15 g and was composed primarily of dilated cystic acinar areas with only modest stromal thickening. The acini were lined by a low cuboidal epithelium. A second minor population of smaller glands with extensive papillary projections was also present. The epithelial cells stained densely for acid phosphatase and prostatic-specific antigen. Human prostatic acid phosphatase content of the gland as determined by radioimmunoassay was 2.3 mg/g protein. This is the first published histologic description of a gorilla prostate. The animal was in late middle age but did not display predominant prostatic stromal hyperplasia. Prostatic acid phosphatase from the gorilla cross-reacts immunologically, or is identical to human prostatic acid phosphatase.