Melatonin hormone profile in infertile males

Abstract

Melatonin is a hormone produced by the pineal gland. There is much controversy about its relationship to the male reproductive process. In this study, seminal plasma as well as the serum melatonin levels were studied in different infertile male groups and were correlated with their semen parameters and hormonal levels. One hundred twenty male cases subdivided into six equal groups were consecutively included; fertile normozoospermic men, oligoasthenozoospermia (OA), OA with leucocytospermia, OA with varicocele, non-obstructive azoospermia (NOA) with high serum follicle stimulating hormone (FSH) and NOA with normal FSH. Semen analysis, estimation of melatonin, FSH, testosterone (T) and prolactin (PRL) hormone was carried out. Mean level of serum melatonin was higher than its corresponding seminal concentrations in all investigated groups with a positive correlation between their levels (r = 0.532, p = 0.01). Serum and seminal plasma melatonin levels in all infertile groups were reduced significantly compared with their levels in the fertile group. The lowest concentrations were in OA with leucocytospermia group. Melatonin in both serum and semen demonstrated significant correlation with sperm motility (r = 607, 0.623 respectively, p = 0.01). Serum melatonin correlated positively with serum PRL (r = 0.611, p = 0.01). It may be concluded that melatonin may be involved in the modulation of reproductive neuroendocrine axis in male infertility. Also, low levels of melatonin in semen were observed in infertile groups having reduced sperm motility, leucocytospermia, varicocele and NOA.

Antioxidant Systems and Oxidative Stress in the Testes

“…Secondly, melatonin is readily soluble in both lipid and aqueous environments and can readily cross the blood-testes barrier to protect the germinal epithelium. Melatonin levels in seminal plasma are depressed in infertile patients exhibiting poor motility, leukocytospermia, varicocele and non-obstructive azoospermia, all of which are conditions associated with oxidative stress in the male tract 44. Moreover, the intraperitoneal injection of melatonin has been shown to alleviate oxidative stress in the testes following the experimental induction of a left sided varicocele 45…”

Local Actions of Melatonin in Somatic Cells of the Testis

“…Melatonin seems to protect human spermatozoa from apoptosis [112]. At this point, low melatonin levels have been associated with reduced sperm motility and abnormal sperm progression in infertile patients [113,114]. Moreover, melatonin levels in serum and seminal plasma of infertile patients suffering from oligoasthenozoospermia or non-obstructive azoospermia are significantly reduced compared with those quantified in fertile men [114].…”

Local Actions of Melatonin in Somatic Cells of the Testis

“…Melatonin also seems to protect human spermatozoa from apoptosis [34]. In fact, low melatonin levels have been associated with reduced sperm motility and abnormal sperm progression [35,36]. Moreover, melatonin serum and seminal plasma levels in infertile patients suffering from oligoasthenozoospermia or non-obstructive azoospermia are significantly reduced compared with those quantified in fertile men [36].…”