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Gen Comp Endocrinol 2018 02 19;257:122-129. Epub 2017 Aug 19.

Department of Organismal Biology, Comparative Physiology, Evolutionary Biology Centre, Uppsala University, SE-752 36 Uppsala, Sweden. Electronic address:

Leptin modulates all levels of the reproductive endocrine axis in mammals, and in turn, both leptin and the leptin receptor are regulated by sex steroids. The aim of this study was to investigate if sex steroids regulate the leptin system also in fish. Immature one-year old male Atlantic salmon parr were implanted with Silclear capsules that were either empty or filled with 11-ketoandrostenedione (11KA) or testosterone (T) and the effects of 35-days treatment were investigated on measures of maturation, gene expression of leptin (lepa1, lepa2), leptin receptor (lepra1) and circulating plasma leptin. Read More

PLoS One 2015 30;10(9):e0138857. Epub 2015 Sep 30.

Department of Arctic and Marine Biology, UiT-The Arctic University of Norway, Tromsø, Norway.

The highly seasonal anadromous Arctic charr (Salvelinus alpinus) was used to investigate the possible involvement of altered gene expression of brain neuropeptides in seasonal appetite regulation. Pro-opiomelanocortin (POMCA1, POMCA2), Cocaine and amphetamine regulated transcript (CART), Agouti related Peptide (AgRP), Neuropeptide Y (NPY) and Melanocortin Receptor 4 (MC4-R) genes were examined. The function of centrally expressed Leptin (Lep) in fish remains unclear, so Lep (LepA1, LepA2) and Leptin Receptor (LepR) genes were included in the investigation. Read More

Gen Comp Endocrinol 2015 Sep 30;221:156-64. Epub 2015 Jan 30.

Department of Organismal Biology, Comparative Physiology, Evolutionary Biology Centre, Uppsala University, SE-752 36 Uppsala, Sweden. Electronic address:

In mammals, leptin plays an important role in puberty and reproduction and leptin is regulated by sex steroids. Elevated leptin levels have been associated with sexual maturation in some teleosts such as Atlantic salmon. In the present study, primary cultures of Atlantic salmon hepatocytes were used to investigate the direct effects of different sex steroids on expression of the two salmon leptin-a genes, lepa1 and lepa2. Read More

Gen Comp Endocrinol 2014 Aug 10;204:60-70. Epub 2014 May 10.

Department of Organismal Biology, Comparative Physiology, Evolutionary Biology Centre, Uppsala University, SE-752 36 Uppsala, Sweden. Electronic address:

In mammals, leptin acts as an adiposity signal and is a crucial link between nutritional status and the reproductive axis. So far the link between leptin and energy balance during sexual maturation in teleosts has been poorly investigated. In this study, seasonal gene expression changes in two leptin genes (lepa1 and lepa2) and the leptin receptor were investigated during early sexual maturation in male Atlantic salmon parr under fully fed (control) and feed restricted conditions from April through September. Read More

Gen Comp Endocrinol 2013 Mar 27;183:83-8. Epub 2012 Nov 27.

Department of Biology, University of Bergen, Bergen High Technology Centre, Bergen, Norway.

Atlantic salmon was used to investigate the effect of long- and short-term dietary ration on the tissue expression levels of leptins. Compared to ad libitum fed fish (0.8-3kg), 6months of dietary restriction (60%) resulted in significantly lower body mass and adiposity, but did not produce a clear effect on the expression levels of either lepa1 or lepa2. Read More

Fish Physiol Biochem 2013 Feb 7;39(1):103-6. Epub 2012 Oct 7.

Department of Organismal Biology, Comparative Physiology, Evolutionary Biology Center, Uppsala University, Norbyvägen 18A, 752 36, Uppsala, Sweden.

Leptin plays an important role in energy homeostasis and reproductive function in mammals, while its function in fish is still poorly understood, especially its role in reproduction. In the present study, leptin gene expression and circulating leptin plasma levels were measured during sexual maturation in male Atlantic salmon parr. In maturing male salmon, higher hepatic leptin (lepa1) gene expression levels were observed during mid-spermatogenesis compared to immature fish. Read More

Gen Comp Endocrinol 2012 Sep 23;178(2):330-7. Epub 2012 Jun 23.

Faculty of Biosciences, Fisheries and Economy, University of Tromsø, N-9037 Tromsø, Norway.

The aim of this study was to investigate whether the seasonal feeding cycle of the anadromous Arctic charr (Salvelinus alpinus) is regulated by a lipostatic mechanism and if leptin (Lep) might act as an endocrine signal of adiposity. Offspring of anadromous Arctic charr with a body mass of 121 g were divided into two treatment groups; one was given feed in excess from March to November, and the other was fasted between April and early June and fed in excess thereafter. In the continuously fed group there was an 8-fold increase in body mass, and a doubling of percentage body fat, from March to August, after which there was no further increase. Read More

Gen Comp Endocrinol 2012 Jan 10;175(1):153-62. Epub 2011 Nov 10.

Department of Zoology/Zoophysiology, University of Gothenburg, Box 463, SE-405 30 Gothenburg, Sweden.

The growth-promoting effects of in vivo growth hormone (GH) treatment were studied in relation to size and lipid content of energy stores including liver, mesentery, white muscle and belly flap in rainbow trout. In order to elucidate endocrine interactions and links to regulation of growth, adiposity and energy metabolism, plasma levels of GH, insulin-like growth factor I (IGF-I), leptin (Lep) and ghrelin, were assessed and correlated to growth and energy status. In addition tissue-specific expression of lepa1 mRNA was examined. Read More

Int J Biol Macromol 2012 Jan 6;50(1):214-8. Epub 2011 Nov 6.

School of Military Preventive Medicine, Fourth Military Medical University, Xi'an, China.

The crude polysaccharide (LEP) was extracted by hot water from the fruiting bodies of Lentinus edodes, and further purified by DEAE-cellulose and Sepharose CL-6B chromatography, giving three polysaccharide fractions coded as LEPA1, LEPB1 and LEPC1. In this study, their chemical and physical characteristics of polysaccharide fractions and antioxidant capacities, including scavenging activity against hydroxyl radicals, superoxide radicals and Fe(2+)-chelating ability, were valuated. The results showed that LEPC1 exhibited significantly antioxidant activity at a concentration-dependent manner. Read More

Gen Comp Endocrinol 2012 Jan 12;175(1):92-9. Epub 2011 Oct 12.

Evolutionary Biology Centre, Department of Organismal Biology/Comparative Physiology, Uppsala University, SE-752 36 Uppsala, Sweden.

Leptin is a pleiotropic hormone and plays a key role in body weight regulation, energy homeostasis and lipid store utilization in mammals. In this study, we investigated the effect of feed-restriction on leptin genes (lepa1 and lepa2), leptin receptor (lepr) gene expression and plasma leptin levels in juvenile Atlantic salmon parr. Feed restriction was performed from late April to mid-June, in order to gain insight into the role of the leptin system in energy balance regulation and adiposity in juvenile salmon. Read More

Comp Biochem Physiol A Mol Integr Physiol 2011 Jan 16;158(1):79-86. Epub 2010 Sep 16.

Department of Biology, University of Bergen, Box 7803, NO-5020 Bergen, Norway.

Leptin (Lep) is a key factor for the energy homeostasis in mammals, but the available data of its role in teleosts are not conclusive. There are large sequence differences among mammalian and teleost Lep, both at the gene and protein level. Therefore, in order to characterize Lep function in fish, the use of species-specific Lep is crucial. Read More

Dev Neurobiol 2010 Aug;70(9):649-58

Department of Biology, University of Bergen, Bergen High Technology Center, Norway.

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. Read More