RELATIONSHIP OF TESTICULAR VOLUME TO SEMEN PROFILES AND SERUM HORMONECONCENTRATIONS IN INFERTILE JAPANESE MALES

Objective-We studied the relationship between testicular volume and se men duality and also between testicular volume and seminiferous tubula r or Leydig cell function in infertile Japanese males. Methods-The tes ticular Volumes of 486 infertile Japanese males were measured by an or chidometer. Semen samples were analyzed according to the guidelines of the World Health Organization. Serum concentrations of follicle-stimu lating hormone (FSH), luteinizing hormone (LH), and testosterone were measured by radioimmunoassay. The subjects were divided into 10 groups according to testicular volume, and the variables from each group wer e analyzed and compared. Results-Testicular volume had the strongest p ositive correlation with sperm density, followed in decreasing order b y total sperm count per ejaculate, total motile sperm count per ejacul ate, and percentage of motile sperm. Testicular volume had the stronge st negative correlation with serum FSH concentrations, followed by ser um LH concentrations. In contrast, no significant correlations were fo und between testicular volume and semen volume or serum testosterone c oncentrations. Multiple regression analysis of dependence of testicula r volume on semen profiles and serum hormone concentrations revealed t hat the only significant factor was serum FSH concentration. Sperm den sity was under the limit of normal in patients with a testicular volum e of less than 30 mt. In these patients, serum FSH concentrations were abnormally increased. Patients with a testicular volume of less than 10 mt were azoospermic, while volumes of less than 20 mt were associat ed with severe oligozoospermia. Conclusions-Testicular volume has a di rect correlation with semen profiles, and the critical testicular volu me indicating normal testicular function is approximately 30 mt. The m easurement of testicular volume can be helpful for rapidly assessing f ertility at the initial physical examination.