Leptin, an adipocyte-derived hormone, serves numerous physiological functions in the body, particularly during puberty and reproduction. The exact mechanism by which leptin activates the gonadotropin-releasing hormone (GnRH) neurons to trigger puberty and reproduction remains unclear. Given the widespread distribution of leptin receptors in the body, both central and peripheral mechanisms involving the hypothalamic-pituitary-gonadal axis have been hypothesized. Leptin is necessary for normal reproductive function, but when present in excess, it can have detrimental effects on the male reproductive system. Human and animal studies point to leptin as a link between infertility and obesity, a suggestion that is corroborated by findings of low sperm count, increased sperm abnormalities, oxidative stress, and increased leptin levels in obese men. In addition, daily leptin administration to normal-weight rats has been shown to result in similar abnormalities in sperm parameters. The major pathways causing these abnormalities remain unidentified; however, these adverse effects have been attributed to leptin-induced increased oxidative stress because they are prevented by concurrently administering melatonin. Studies on leptin and its impact on sperm function are highly relevant in understanding and managing male infertility, particularly in overweight and obese men.
The declining trend of male fecundity is a major global health and social concern. Among numerous other confounding factors, variations in male fertility parameters in different regions have repeatedly been suggested to be influenced by geographic locations. The impact of overall lifestyle, behavioural patterns, ethnicity, work stress and associated factors upon health differ greatly between developed and developing countries. These factors, individually or in combination, affect male reproductive functions ensuing the discrepancies in semen qualities in connection with geographic variations. However, reports comparing semen characteristics between developed and developing countries are sparse. The present study finds its novelty in presenting a comparison in semen parameters of infertile men in the United States (n = 76) that fairly represents the population of a highly developed region and Iraq (n = 102), the representative of male populations of a developing region. Samples were collected and analysed according to WHO (WHO laboratory manual for the examination and processing of human semen, WHO; 2010) criteria by means of the Mann-Whitney test. The US population demonstrated lower sperm concentration, total count, and total and progressive sperm motility with a higher seminal total antioxidant capacity (TAC) as compared to the Iraqi population. This report encourages further investigations concerning the confounding factors leading to such alterations in semen qualities between these two geographic areas.
This study investigated the effect of treatment with the proprietary standardized, water-soluble extract of the root of the Malaysian plant, Eurycoma longifolia Jack, which is thought to enhance male fertility with regard to higher semen volumes, sperm concentrations, the percentage of normal sperm morphology and sperm motility in male partners of sub-fertile couples with idiopathic infertility. A total of 350 patients were given 200 mg of the extract daily and follow-up semen analyses were performed every 3 months for 9 months. Of these 350 patients, 75 patients completed one full cycle of 3 months. Follow-up semen analyses in these patients showed significant improvement in all semen parameters. The proprietary extract of Eurycoma longifolia Jack significantly improved the sperm quality in these patients, allowing for 11 (14.7%) spontaneous pregnancies.