Introduction:  Leptin is a 167 - amino acid polypeptide hormone, identified in 1994 by positional cloning in the mouse and human. This hormone is secreted by the white adipose tissue in proportion to body energy (fat) stored. Leptin functions as a satiety factor in the regulation of body weight. So far, many studies have pointed to a direct role of leptin in the control of male reproductive function. However, in contrast to its well proven effects in female fertility.

Materials and Method: one  hundred male partners from infertile couples were included in the study. Based on clinical examination, spermiogram were divided into five groups:20 men with azoospermia, 20 men with oligozoospermia, 20 men with oligoasthenoteratozoospermia,  20 men with normozoospermia. Serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), inhibin and testosterone and leptin were measured.

Results: After adjustment for body mass index, there was a negative correlation between serum levels of leptin and inhibin B, total testosterone (r =-0.189, p =0.009 and  r = -0.250, p  0.001 respectively) but there was no correlation between leptin and classical sperm characteristics. Conclusions: Our results therefore demonstrate a link between leptin and testicular function, independently of FSH and LH, possibly involving testosterone through a regulation of Leydig cell function.