Melatonin and male reproduction.
Melatonin is a neurohormone secreted by the pineal gland whose concentrations in the body are regulated by both the dark-light and seasonal cycles. The reproductive function of seasonal breeding animals is clearly influenced by the circadian variation in melatonin levels. Moreover, a growing body of evidence indicates that melatonin has important effects in the reproduction of some non-seasonal breeding animals. In males, melatonin affects reproductive regulation in three main ways. First, it regulates the secretion of two key neurohormones, GnRH and LH. Second, it regulates testosterone synthesis and testicular maturation. Third, as a potent free radical scavenger that is both lipophilic and hydrophilic, it prevents testicular damage caused by environmental toxins or inflammation. This review summarizes the existing data on the possible biological roles of melatonin in male reproduction. Overall, the literature data indicate that melatonin affects the secretion of both gonadotropins and testosterone while also improving sperm quality. This implies that it has important effects on the regulation of testicular development and male reproduction.
College of Animal Sciences, Jilin University, 5333 Xi'an Avenue, Changchun, Jilin Province 130062, PR China.
Chunjin
C
Li
College of Animal Sciences, Jilin University, 5333 Xi'an Avenue, Changchun, Jilin Province 130062, PR China. Electronic address: xzhou65@vip.sina.com.
Xu
X
Zhou
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002940:Circadian Rhythm / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D056084:Genetic Fitness / Q000235:genetics; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007986:Luteinizing Hormone / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D010870:Pineal Gland / Q000254:growth & development / Q000378:metabolism; D012098:Reproduction / Q000235:genetics*; D055101:Semen Analysis; D015398:Signal Transduction; D013737:Testis / Q000254:growth & development / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism*
D000975:Antioxidants; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007986:Luteinizing Hormone; D008550:Melatonin
Antioxidant; Male reproduction; Melatonin; Sperm; Testis