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Ontogeny of energy homeostatic pathways via neuroendocrine signaling in Atlantic salmon
Author(s) -
Moen AnneGrethe Gamst,
Murashita Koji,
Finn Roderick Nigel
Publication year - 2010
Publication title -
developmental neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.716
H-Index - 129
eISSN - 1932-846X
pISSN - 1932-8451
DOI - 10.1002/dneu.20803
Subject(s) - biology , energy homeostasis , cart , downregulation and upregulation , ghrelin , ontogeny , leptin , medicine , endocrinology , neuropeptide y receptor , homeostasis , neuropeptide , endocrine system , hormone , microbiology and biotechnology , receptor , gene , genetics , mechanical engineering , engineering , obesity
Leptin and ghrelin are known to regulate energy homeostasis via hypothalamic neuropeptide signaling in mammals. Recent studies have discovered that these hormones exist in teleosts, however, very little is known concerning their role during teleost ontogeny. Here, we have examined the steady state levels of leptins, ghrelins, their target neuropetides and several growth factors during Atlantic salmon development. Initial experiments revealed differential expression of leptin genes and ghrelin isoforms during embryogenesis. In larvae, equal upregulation of ghrl1 and ghrl2 was observed just prior to exogenous feeding while a surge of lepa1 occurred one week after first‐feeding. Subsequent dissection of the embryos and larvae showed that lepa1 , cart , pomca1, and agrp are supplied as maternal transcripts. The earliest zygotic expression was observed for lepa1 and cart at 320 day degrees. By 400 day degrees, this expression was localized to the head and coincided with upregulation of ghrl2 and npy . Over the hatching period growth factor signaling predominated. The ghrelin surge prior to first‐feeding was exclusively localized in the internal organs and coincided with upregulation of npy and agrp in the head and agrp in the trunk. One week after exogenous feeding was established major peaks were detected in the head for lepa1 and pomca1 with increasing levels of cart , while lepa1 was also significantly expressed in the trunk. By integrating theses data into an ontogenetic model, we suggest that the mediation of Atlantic salmon energy homeostatic pathways via endocrine and neuropeptide signaling retains putative features of the mammalian system. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 649–658, 2010