Roles of leptin and ghrelin in adipogenesis and lipid metabolism of rainbow trout adipocytes in vitro

• Leptin and ghrelin are important regulators of energy homeostasis in mammals, whereas their physiological-roles in fish have not been fully elucidated. In the present study, the effects of leptin and ghrelin on adipogenesis, lipolysis and on expression of lipid metabolism-related genes were examined in rainbow trout adipocytes in vitro. Leptin expression and release increased from preadipocytes to mature adipocytes in culture, but did not affect the process of adipogenesis. While ghrelin and its receptor were identified in cultured differentiated adipocytes, ghrelin did not influence either preadipocyte proliferation or differentiation, indicating that it may have other adipose-related roles. Leptin and ghrelin increased lipolysis in mature freshly isolated adipocytes, but mRNA expression of lipolysis markers was not significantly modified. Leptin significantly suppressed the fatty acid transporter-1 expression, suggesting a decrease in fatty acid uptake and storage, but did not affect expression of any of the lipogenesis or beta-oxidation genes studied. Ghrelin significantly increased the mRNA levels of lipoprotein lipase, fatty acid synthase and peroxisome proliferator-activated receptor-beta, and thus appears to stimulate synthesis of triglycerides as well as their mobilization. Overall, the study indicates that ghrelin, but not leptin seems to be an enhancer of lipid turn-over in adipose tissue of rainbow trout, and this regulation may at least partly be mediated through autocrine/paracrine mechanisms. The mode of action of both hormones needs to be further explored to better understand their roles in regulating adiposity in fish. (C) 2015 Elsevier Inc. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Biologi -- Zoologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Zoology (hsv//eng)

Nyckelord

Leptin

Ghrelin

Insulin

Adipocyte primary culture

Isolated mature adipocytes

Lipolysis

receptor (ghs-r)-like receptor

messenger-rna expression

bream

sparus-aurata

oncorhynchus-mykiss

gene-expression

food-intake

sea

bream

oreochromis-mossambicus

cultured preadipocytes

3t3-l1

preadipocytes

Biochemistry & Molecular Biology

Physiology

Zoology

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