A spontaneous, nonacute, age-dependent prostatitis was found in a high incidence in the lateral prostatic lobes of Lewis rats. Such rats were treated with methylprednisolone, indometacin , testosterone, hexyloxyphenylproprionate , polyestradiol phosphate, various antibiotics, or were caged together with female rats. The effect of the different treatment modalities was evaluated microscopically by blind observation of the degree of inflammatory reaction in the lateral prostate. Methylprednisolone and the testosterone ester caused a reduction of the inflammatory reactions and so did caging with female rats. The similarity of the rat prostatitis to the human condition may suggest the possibility of using corticosteroids or androgens for the treatment of patients with nonacute prostatitis.

A high incidence of spontaneous, non-acute, age-dependent prostatitis was observed in the lateral prostate of Copenhagen rats and Wistar rats. The lumen of infected acini was filled with polymorphonuclear leucocytes, shed epithelial cells and cell residues. Epithelial cells lining such acini showed degenerative changes. Lymphocytes and macrophages were seen in the stroma. A histochemically observed increase in acid phosphatase and beta-glucuronidase activity in affected epithelial cells may indicate an increased lysosomal activity. Some bacteriological cultures of infected lateral prostates were positive for Proteus vulgaris and diphtheroids. It is suggested that this spontaneous rat prostatitis may be a useful model for the study of the pathogenesis and treatment of human non-acute prostatitis.

The results show that the pollen extract in Femal does not give the preparation any estrogenic effect. Thus, Femal, which has proven clinical efficacy, is a nonestrogenic alternative to hormone therapy in women with menopausal symptoms.

Ultrastructural, histological, and immunohistochemical studies were performed on lateral prostates of 1) aged rats from different strains, 2) rats permitted different levels of sexual activity, and 3) castrated rats. Antibodies against the following proteins were used as immunohistochemical markers: SVS II from seminal vesicle, LP 28 from lateral prostate, acid phosphatase isoenzymes from ventral prostate, transglutaminase from coagulating gland, and a commercial monoclonal antibody against cytokeratin. SVS II is a marker of lateral prostatic secretion, while immunoreactions to LP 28 and acid phosphatase (pI 7.1) were cytoplasmic. In aged animals the amount of intracellular secretion is decreased, and focally metaplastic transformation can be visualized by using immunohistochemical markers. Epithelial ultrastructure varied considerably with experimental conditions. Intensive sexual activity resulted in increased polymorphism and increased number of secretory granules within the glandular cells, while castration was followed by a rapid loss of secretory material. Also, in rats older than 10 months, a reduction in the number of secretion granules was common. The epithelium developed a positive immunoreaction to transglutaminase antibodies that were not observed in juvenile glands. Cells, presumably macrophages, which had an intense immunoreactivity for transglutaminase, were increased in number both within and outside the prostatic acini of aged rats. The possible interaction between secretory SVS II, a substrate of transglutaminase, the release of this enzyme from macrophages or its reflux from coagulating glands, the spontaneous cellular exfoliation that is due to decreased androgen levels, and dietary noxae may be of importance in the development of lateral prostatic nonbacterial inflammation in aged rats.

With the aim of studying a possible role of the fibromuscular stroma as growth regulator for the rat ventral prostate the weight, DNA content, and hydroxyproline content were analyzed in the ventral prostate of rats of varying age. Exogenous androgen increased the age-dependent weight and contents only in young and old rats. Orchiectomy reduced prostatic weight, DNA content, and hydroxyproline content although to different extent, and exogenous androgen restored the weight and contents. Exogenous estrogen to intact animals had effects similar to orchiectomy. Estrogen combined with androgen increased DNA content over that found in animals given androgen only, while weight and hydroxyproline content were not changed. It is concluded that the endogenous androgen determines the size of the prostate in young and old animals. Androgen also determines prostatic collagen content. The good correlation between prostatic DNA and hydroxyproline indicates a more or less fixed number of epithelial cells per amount of collagen. A hypothesis suggesting a crucial role for prostatic collagen in the growth-limiting mechanism in the prostate is presented.