HUMAN LEYDIG-CELLS AND SERTOLI CELLS ARE PRODUCERS OF INTERLEUKIN-1 AND INTERLEUKIN-6

Interleukins (IL)-1 and -6 have been shown to be produced by several c ategories of cells in the rat testis and involved in the paracrine con trol of testicular function. Evidence of high amounts of IL-1 have bee n shown in the human testis, but nothing is known about its cellular o rigin. Furthermore, to our knowledge, the presence of IL-6 in the huma n testis has not yet been investigated. Therefore, the present study w as aimed at identifying IL-1 and -6 expression and production within t he human testis, using RT-PCR, bioassays, and enzyme linked immunosorb ent assays. We demonstrated that IL-1 and -6 messenger RNA and protein s were produced constitutively in vitro by human Leydig cell- and Sert oli cell-enriched preparations. FSH only stimulated IL-6 production by Sertoli cell-enriched preparations, but increased the release of both IL-1 and -6 in germ cell-depleted Sertoli cell cultures. In addition, lipopolysaccharides and latex beads enhanced the production of both c ytokines by Sertoli cell cultures, whereas human chorionic gonadotropi n and lipopolysaccharides enhanced the release of both cytokines by Le ydig cells. Enzyme linked immunosorbent assays and neutralization expe riments revealed that human Sertoli cells produce essentially the alph a form of IL-1, whereas both forms, alpha and beta, are present in Ley dig cells. The demonstration that human Leydig and Sertoli cells produ ce IL-1 and -6 under the control of gonadotropin hormones and exogenou s factors, opens the possibility to study the involvement of these cyt okines in the control of testis function, in normal and pathological c onditions in men.