Production, gene structure and characterization of two orthologs of leptin and a leptin receptor in tilapia

Cloning, tissue distribution and effects of fasting on mRNA expression levels of leptin and ghrelin in red-bellied piranha (Pygocentrus nattereri)

“…This widespread distribution of leptin has also been observed in other fish species, such as zebrafish (Gorissen et al, 2009), yellow catfish, Pelteobagrus fulvidraco (Gong et al, 2013), Chinese perch, Siniperca chuatsi (He et al, 2013), common carp (Tang et al, 2013), Atlantic salmon (Ronnestad et al, 2010), grouper , Ya fish, Schizothorax prenanti and tilapia (Shpilman et al, 2014). Leptin-like immunoreactivity has also been shown in stomach and/or intestine of several fish species, including trout (Bosi et al, 2004;Ettore et al, 2012;Muruzabal et al, 2002), Murray cod, Maccullochella peelii peelii (Ettore et al, 2012), seabass, Dicentrarchus labrax (Gambardella et al, 2010a;Russo et al, 2011), goldfish C. auratus (Russo et al, 2011) and small-spotted catshark, Scyliorhinus canicula (Gambardella et al, 2010b), suggesting that leptin could have peripheral actions on both gastrointestinal processes and regulation of feeding.…”

“…Inconsistent results have been obtained in previous studies examining the effects of fasting on leptin mRNA expression in fish, perhaps indicative of species-and tissue-specific roles for leptin in the regulation of food intake and energy metabolism. Fasting does not affect leptin expression in either liver or hypothalamus of goldfish (Tinoco et al, 2012), brain of tilapia, Oreochromis niloticus (Shpilman et al, 2014) or liver of common carp (Huising et al, 2006), suggesting that leptin might not be involved the long-term regulation of food intake and energy metabolism in these species. In other fish species, species-specific fasting-induced changes in the leptin system have been observed.…”

Two leptin genes and a leptin receptor gene of female chub mackerel (Scomber japonicus): Molecular cloning, tissue distribution and expression in different obesity indices and pubertal stages

“…Based on structural analysis using 3D modeling, chub mackerel leptin was highly conserved with human leptin-containing four a-helix domainsthis sequence and structural characteristics correspond with those of all fish species reported. However, a recent study indicated that mammalian leptin showed low affinity for the Nile tilapia piscine leptin receptor (Shpilman et al, 2014). Nevertheless, the leptins of mammals and fish differ both functionally and physiologically.…”

“…Notably, Salmonidae and Cyprinidae possess duplicated lepa genes (lepa-1 and lepa-2). Conversely, not only lepa but also a highly divergent leptin gene, lepb, have been found in the zebrafish (Danio rerio) (Gorissen et al, 2009), medaka (Oryzias latipes) , orange spotted grouper (Epinephelus coioides) (Zhang et al, 2013) and Nile tilapia (Oreochromis niloticus) (Shpilman et al, 2014). In mammalians, leptin is produced by fat cells and previous reports showed that leptin genes are expressed primarily in the liver of fish (Gorissen et al, 2009;Huising et al, 2006;Kurokawa et al, 2005;Rønnestad et al, 2010;He et al, 2013).…”

Effects of recombinant human leptin administration on hepatic lipid metabolism in yellow catfish Pelteobagrus fulvidraco: In vivo and in vitro studies

“…In mammals, leptin, a hormone secreted from adipose tissue, is a member of the class-1 alpha helical cytokines (Zhang et al, 1994). Since its discovery in 1994, the biology and physiological roles of leptin has been extensively studied, with the special emphasis on the regulation of food intake and energy homeostasis (Friedman and Halaas, 1998;Klok et al, 2007), but information regarding its role in teleosts is still limited (Volkoff et al, 2003;de Pedro et al, 2006;Shpilman et al, 2014). In contrast to mammals, whose adipose tissue is the main site of leptin synthesis (Zhang et al, 1994;Montague et al, 1997), in fish the liver was an important site for leptin expression (Kurokawa et al, 2005;Murashita et al, 2008;Gong et al, 2013).…”