Serum levels of dimeric and monomeric inhibins and the degree of seminal alteration in infertile men with varicocele

The aim of the present study was to establish the serum levels of inhibins and their relationship with the degree of seminal alteration in infertile men. Thirty-six patients with varicocele (Va) and seven non-obstructive azoospermic men (Az) were included. The Va group was divided into two subgroups: Va I (sperm concentration: >20 x 106; n = 21) and Va II (sperm concentration: < 20 x 106; n = 15). Twelve fertile men were included as a control group (Co). Semen analysis and serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), inhibin B and Pro-alphaC levels were determined. Serum inhibin B and T levels were significantly lower and FSH and LH significantly higher in group Az when compared with the Co. Inhibin B was unable to differentiate Va I from Va II groups. However, in Va II an increase in FSH levels was observed. An inverse correlation between inhibin B and FSH, a direct correlation between inhibin B and testosterone, sperm concentration, motility and morphology were found. No such correlations were seen when only the Va group was analysed. The lack of correlation between serum levels of inhibin B, gonadotrophins, sperm concentration and seminal parameters observed in Va, adds other factor to the complex pathophysiology of varicocele. Finally, further studies are needed to elucidate if oligozoospermic patients with varicocele have also an impaired negative feed-back mechanism that regulates FSH synthesis and secretion.