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Titolo:
Roles of melatonin in gonadal maturation of underyearling precocious male masu salmon
Autore:
Amano, M; Iigo, M; Ikuta, K; Kitamura, S; Yamada, H; Yamamori, K;
Indirizzi:
Kitasato Univ, Sch Fisheries Sci, Sanriku, Iwate 0220101, Japan Kitasato Univ Sanriku Iwate Japan 0220101 , Sanriku, Iwate 0220101, Japan St Marianna Univ, Sch Med, Dept Anat, Kawasaki, Kanagawa 2168511, Japan StMarianna Univ Kawasaki Kanagawa Japan 2168511 Kanagawa 2168511, Japan Natl Res Inst Aquaculture, Nikko Branch, Utsunomiya, Tochigi 3211661, Japan Natl Res Inst Aquaculture Utsunomiya Tochigi Japan 3211661 3211661, Japan
Titolo Testata:
GENERAL AND COMPARATIVE ENDOCRINOLOGY
fascicolo: 2, volume: 120, anno: 2000,
pagine: 190 - 197
SICI:
0016-6480(200011)120:2<190:ROMIGM>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
GONADOTROPIN-RELEASING-HORMONE; TROUT ONCORHYNCHUS-MYKISS; RAINBOW-TROUT; BINDING-SITES; CARASSIUS-AURATUS; NONMAMMALIAN VERTEBRATES; ATLANTIC SALMON; BRAIN; PHOTOPERIOD; GOLDFISH;
Keywords:
melatonin; oral administration; photoperiod; testicular maturation; masu salmon;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Amano, M Kitasato Univ, Sch Fisheries Sci, Sanriku, Iwate 0220101, Japan Kitasato Univ Sanriku Iwate Japan 0220101 , Iwate 0220101, Japan
Citazione:
M. Amano et al., "Roles of melatonin in gonadal maturation of underyearling precocious male masu salmon", GEN C ENDOC, 120(2), 2000, pp. 190-197

Abstract

Testicular maturation of underyearling precocious male masu salmon (Oncorhynchus masou) is affected by photoperiod. It is accelerated by a short photoperiod (light-dark cycles of 8:16 h; LD 8:16) and delayed by a long photoperiod (LD 16:8). Circulating melatonin levels are high during the night andlow during the day:the duration of the nocturnal elevation is longer undera short than under a long photoperiod, suggesting mediation of photoperiodic signals by melatonin. This study examined whether melatonin administration mimics short photoperiodic effects and whether it accelerates the testicular development of underyearling male masu salmon reared under a long photoperiod. Fish were randomly selected in June and were divided into two groups. They were reared under LD 16:8 (lights on 04:00-20:00 h) and fed pellets sprayed with melatonin (0.5 mg melatonin/kg body weight/day) or vehicle once a day at 11:00 h until October. The plasma melatonin profile of the melatonin-treated group was similar to that expected under a short photoperiod. Melatonin treatment had a stimulatory effect on the gonadosomatic index and pituitary gonadotropin (GTH) I contents. plasma testosterone levels weresignificantly higher in the melatonin-treated group than in the control group in August. However, spermiation was observed in October in both groups and no significant differences were observed in GTH II contents in the pituitary in the two groups throughout the experiment. These results suggest that mimicking a short photoperiod by melatonin administration stimulated testicular development but did not completely activate the brain-pituitary-gonadal axis in precocious male masu salmon. Thus, melatonin is suggested to be one of the factors that mediates the transduction of photoperiodic information to the brain-pituitary-gonadal axis. (C) 2000 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 22/01/20 alle ore 22:28:29