Leptin levels in infertile male patients are correlated with inhibin B, testosterone and SHBG but not with sperm characteristics

In the present study, differences in leptin levels between different groups of male patients presenting with infertility problems and possible correlations between leptin levels and clinical, spermiological, histological and hormonal characteristics were examined. Two hundred and ten male partners from infertile couples were included in the study. Based on clinical examination, spermiogram and testicular histology results, patients were divided into four groups: 42 men with non-obstructive azoospermia, 15 men with obstructive azoospermia, 68 men with oligoasthenoteratozoospermia and 85 men with normozoospermia. Serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), inhibin B, testosterone, sex hormone binding globulin (SHBG) and leptin were measured. After adjustment for body mass index, there was a negative correlation between serum levels of leptin and inhibin B, total testosterone and SHBG (r = -0.189, p = 0.009, r = -0.250, p = 0.001 and r =-0.221, p = 0.003 respectively) but there was no correlation between leptin and classical sperm characteristics. Our results therefore demonstrate a link between leptin and testicular function, independently of FSH and LH, possibly involving testosterone and SHBG through a regulation of Leydig cell function.