Thanyaporn SenaraiJirawat SaetanMontakan TamtinWattana WeerachatyanukulPrasert SobhonPrepee SretarugsaMahidol UniversityPrince of Songkla UniversityCoastal Fisheries Research and Development BureauBurapha University2018-12-112019-03-142018-12-112019-03-142016-08-01Cell and Tissue Research. Vol.365, No.2 (2016), 265-277143208780302766X2-s2.0-84958752203https://repository.li.mahidol.ac.th/handle/123456789/42929© 2016, Springer-Verlag Berlin Heidelberg. Our previous studies have demonstrated that lamprey gonadotropin-releasing hormone-III (lGnRH-III)-like peptide occurs in the central nervous system (CNS) of decapod crustaceans (Macrobrachium rosenbergii, Penaeus monodon, Portunus pelagicus), and that lGnRH-III is the most potent in stimulating ovarian maturation compared with other GnRH isoforms. In this study, we examined the localization of lGnRH-III-like peptide in the CNS and male reproductive organs of the blue swimming crab by using anti-lGnRH-III as a probe. In the brain, lGnRH-III immunoreactivity (−ir) was detected in neurons of clusters 6, 10, 11, 14/15, 16, and 17 and in many neuropils. In the subesophageal ganglion, lGnRH-III-ir was present in neurons of the dorso-lateral and ventro-medial clusters. In the thoracic ganglia, lGnRH-III-ir was observed in the large-sized neurons between the thoracic neuropils and in the ventromedial cluster of the abdominal ganglia. In the testis, lGnRH-III-ir was detected in nurse cells, hemocytes, spermatids 2, and the outer and inner zones of the acrosomes of spermatozoa. Bioassay showed that lGnRH-III significantly increased the testis-somatic index, the percentage of late stages of seminiferous tubules (stages VII–IX), the diameter of the seminiferous tubules, and the number of BrdU-labeled early germ cells compared with the control groups. Thus, lGnRH-III-like peptide exists in the male crab and possibly enhances germ cell proliferation and maturation in the testes, leading to increased sperm production.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyMedicineArticleSCOPUS10.1007/s00441-016-2375-0