ABSTRACT
<p><b>OBJECTIVE</b>To investigate the expression of inhibin B betaB subunits in human testicular tissues.</p><p><b>METHODS</b>Eighty-three cases of the azoospermia underwent testicular biopsy. In accordance with the pathological alterations of spermatogenesis, the samples were divided into four groups: Sertoli-cell-only syndrome (n = 21); hypospermatogenesis (n = 20), maturation arrest (n = 24) and almost normal spermatogenesis (n = 18). Immunohistochemical staining for inhibin B betaB subunits was conducted on the paraffin-embedded sections of different spermatogenesis to localize inhibin B betaB subunits in the seminiferous tubules.</p><p><b>RESULTS</b>Immunohistochemically, positive products of inhibin B betaB subunits were found in both the seminiferous tubules and interstitial tissues of the testis as brown or yellow particles in the cytoplasm. Leydig cells and early intermediate spermatogenic cells showed a very strong positivity; Sertoli cells in the seminiferous tubules were mostly positive; peritubular myoid cells showed a weak positive staining; but no positive expression of inhibin B betaB subunits was found in late spermatids and mature sperm.</p><p><b>CONCLUSION</b>Inhibin B may be produced by both Sertoli cells and early spermatogenic cells in the seminiferous tubules.</p>