STAGE-SPECIFIC IDENTIFICATION OF THE EXPRESSION OF GNRH MESSENGER-RNAAND LOCALIZATION OF THE GNRH RECEPTOR IN MATURE RAT AND ADULT HUMAN TESTIS

Purpose: To identify the expression of gonadotropin-releasing hormone (GnRH) messenger ribonuclueic acid (mRNA) and localize GnRH receptors in mature rat and adult human testes. Materials and Methods: In situ h ybridization and enzymatic receptor binding localization were performe d. Results: GnRH mRNA was expressed within the seminiferous tubules in both mature rat and adult human testis. In rats, expression of GnRH m RNA was identified in the Sertoli cells and spermatogenic cells of som e seminiferous tubules, but the other tubules did not express any hybr idization signal. In humans, expression of GnRH mRNA was identified on ly in some spermatogenic cells in some seminiferous tubules. The recep tors for GnRH were localized to cells in the interstitial tissues of t he testis, probably Leydig cells. Conclusion: The authors believe that the mature rat and adult human seminiferous tubular cells produce GnR H at the same specific stage of the spermatogenic cycle and that GnRH produced within seminiferous tubules, including Sertoli cells and sper matogenic cells, reacts with neighboring GnRH receptors in interstitia l cells, including Leydig cells. The GnRH produced from the Sertoli ce lls in seminiferous tubules would react with GnRH receptors in interst itial cells as a paracrine hormone.