Secretory immune system of the male reproductive tract: effects of dihydrotestosterone and estradiol on IgA and secretory component levels.

Immunoglobulin A (IgA) is present at mucosal sites of the body which are exposed to the external environment. In this study we evaluated the levels of IgA and its transport protein secretory component (SC) in organs of the male reproductive tract of both intact and castrate-hormone-treated rats. Our goals were to determine whether these proteins are present in the male reproductive tract and whether sex hormones can influence the amounts of IgA and SC in selected organs. We found that in intact animals, IgA was present in the prostate, epididymis, vas deferens and testis and that SC levels in the prostate were 22-fold greater than in these same organs. Dihydrotestosterone (DHT) and/or estradiol, when administered to castrate animals, dramatically increased the levels of prostatic SC. In contrast, the levels of IgA were only minimally affected. DHT administration also resulted in a significant increase in SC found in the seminal vesicles. These studies demonstrate that IgA and SC are present in the male reproductive tract of the rat. Further, they show that androgens and estrogens act at selected sites in the male reproductive tract to play an important role in maintaining SC levels and thereby suggest that these hormones influence the movement of IgA from tissues into secretions.