OBJECTIVETo investigate the relationship between pathological alterations of spermatogenic impairment in seminiferous tubules and serum inhibin B concentration in patients with azoospermia and to verify the significance of INH B in evaluating spermatogenesis.

METHODSEighty-three cases of azoospermia underwent testicular biopsy for the purpose of diagnosis. In accordance with the pathological alterations of spermatogenesis in seminiferous tubules, 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). Serum INHB and FSH, LH, T concentrations were tested before testicular biopsy for each patient respectively.

RESULTSThe INHB levels were (20. 85 +/- 18.78) pg/ml, (67.25 +/- 40.98) pg/ml, (73.63 +/- 25.54) pg/ml and (149.48 +/- 27.92) pg/ml in the above four groups, respectively. There was no significant statistical difference in the level of serum INH B between maturation arrest and hypospermatogenesis groups (P > 0.05), and there was a very significant difference in almost normal spermatogenesis group and the other three groups, respectively (P < 0.001). There was no significant difference in the concentration of serum FSH when maturation arrest group compared with spermatogenesis group (P > 0.05), whereas between the other two groups and between each of them and maturation arrest or almost normal spermatogenesis there was a very significant difference in the level of serum FSH (P < 0.05); The concentrations of LH and T were not significantly different among the four groups (P > 0.05).

CONCLUSIONSerum INHB concentration was decreased when spermatogenesis got impaired. It dropped the most markedly in Sertoli cell-only syndrome group. INH B reflects directly the spermatogenic function in seminiferous tubules of the testis. Therefore, it could be considered valuable for spermatogenesis and potential fertility in patients with azoospermia.