title: Unpredictable chronic stress-induced reproductive suppression associated with the decrease of kisspeptin immunoreactivity in male mice.
abstract: Environmental stress affects various parts of mammals typically through the circulation of stress hormones. It has been identified as one of the possible reasons for male reproductive difficulties, but the complex mechanisms responsible for stress-induced reproductive suppression are poorly understood. Here, we examined the relationship between chronic environmental stress and hypothalamic kisspeptin, a recently discovered upstream regulator of the reproductive endocrine feedback system. We studied male mice under an unpredictable chronic stress procedure to replicate the situation of animals under chronic stress. Histological and immunohistochemical analyses were performed focusing on kisspeptin neurons in the arcuate hypothalamic nucleus (ARC) and DNA fragmented cells in seminiferous tubules. Although the ARC was not morphologically altered in either the stressed or non-stressed group, granular kisspeptin immunoreactivities decreased slightly in the stress group. In the testes of the stress group, several signs of testicular degeneration were observed, including increased numbers of ssDNA-positive cells per seminiferous tubule, thinning, vacuoled seminiferous epithelia and multinucleated giant cells. The decreases in kisspeptin in the stress group might be due to other hypothalamic peptides, such as corticotropin-releasing hormone and leptin, whose receptors are known to coexpress in the ARC. In addition, environmental stress directly and indirectly affects testicular function through stress hormones and gonadotropins. In summary, our findings enhance the understanding of stress-induced reproductive suppression possibly mediated by kisspeptin in the ARC.
authors.affiliation: Laboratory of Molecular Morphology, Department of Animal Science, Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo 657-8501, Japan.
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Hirano
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Takuya
authors.initials: T
authors.lastname: Omotehara
authors.forename: Atsutoshi
authors.initials: A
authors.lastname: Tatsumi
authors.forename: Rie
authors.initials: R
authors.lastname: Hashimoto
authors.forename: Yuria
authors.initials: Y
authors.lastname: Umemura
authors.forename: Daichi
authors.initials: D
authors.lastname: Nagahara
authors.forename: Youhei
authors.initials: Y
authors.lastname: Mantani
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Yokoyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitagawa
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Hoshi
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism / Q000502:physiology*; D053938:DNA Fragmentation; D007150:Immunohistochemistry; D059648:Kisspeptins / Q000032:analysis / Q000378:metabolism / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011897:Random Allocation; D012098:Reproduction / Q000502:physiology*; D018709:Statistics, Nonparametric; D013312:Stress, Physiological / Q000502:physiology*; D013737:Testis / Q000502:physiology*
chemical_list: D059648:Kisspeptins