RESUMO
Ghrelin (orexigenic) and nesfatin-1 (anorexigenic) are two peptides with opposing actions on food intake regulation and are mainly expressed in the hypothalamus and gut of mammals and fish. Both are involved in the regulation of a wide range of physiological processes in vertebrates, including metabolism, growth, and reproduction. However, the anatomical relationship between these peptides and the nutrient assimilation processes are not well understood. Thus, the aim of this work was to determine the localization of ghrelin, nesfatin-1, and several enzymes involved in the digestive process (lipoprotein lipase, aminopeptidase A, trypsin, and sucrase-isomaltase) in the intestine of pejerrey (Odontesthes bonariensis), a species with commercial importance in South America. We observed co-localization of ghrelin and nesfatin-1 in enteroendocrine cells, absorptive cells, and in cells of the lamina propia. Approximately half of the cells displaying ghrelin-like immunoreactivity co-localized the NUCB2/nesfatin-1-like signal. In addition, both peptides showed co-localization with lipoprotein lipase, aminopeptidase A, trypsin, or sucrase-isomaltase. All digestive enzymes except for aminopeptidase A and trypsin, showed high co-localization (68-88%) with both ghrelin-like and NUCB2/nesfatin-1-like signals in absorptive, enteroendocrine, and lamina propria cells. Together, our results provide immunohistochemical evidence supporting a role for both ghrelin and NUCB2/nesfatin-1 in the regulation of nutrient assimilation in fish. Anat Rec, 302:973-982, 2019. © 2018 Wiley Periodicals, Inc.
Assuntos
Proteínas de Peixes/análise , Peixes/metabolismo , Grelina/análise , Mucosa Intestinal/enzimologia , Nucleobindinas/análise , Animais , Proteínas de Peixes/metabolismo , Grelina/metabolismo , Imuno-Histoquímica , Nucleobindinas/metabolismo , Nutrientes/metabolismo , América do SulRESUMO
Pejerrey, Odontesthes bonariensis, is an euryhaline fish of commercial importance in Argentina. This work aimed to determine if water salinity affects the expression of genes involved in somatic growth (gh; ghr-I; ghr-II; igf-I), lipid metabolism (Δ6-desaturase) and food intake (nucb2/nesfatin-1). First, we identified the full-length cDNA sequences of Δ6-desaturase (involved in lipid metabolism) and nesfatin-1 (an anorexigen). Then, pejerrey juveniles were reared during 8weeks in three different water salinity conditions: 2.5g/L (S2.5), 15g/L (S15) and 30g/L (S30) of NaCl. Brain, pituitary, liver and muscle samples were collected in order to analyze mRNA expression. The expression of gh and ghr-II mRNAs increased in the pituitary of fish reared at S2.5 and S30 compared with the S15 group. The expression of ghr-I was higher in the liver of S30 group compared to S2.5 and S15. Igf-I mRNA expression in liver increased with the increment of water salinity, while it decreased in the muscle of S15 and S30 groups. Δ6-desaturase expression increased in S2.5 group compared to S15 in both liver and muscle. S30 caused a decrease in the Δ6-desaturase expression in liver compared to S15. The S30 treatment produced an increase in nucb2/nesfatin-1 mRNA expression in the brain and liver compared to S2.5 and S15. The changes in gene expression observed could help pejerrey perform better during salinity challenges. The S30 condition would likely promote pejerrey somatic growth in the long term.
Assuntos
Ingestão de Alimentos/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Perciformes/genética , Cloreto de Sódio/farmacologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , DNA Complementar/genética , DNA Complementar/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Ingestão de Alimentos/genética , Hormônio do Crescimento/genética , Hormônio do Crescimento/metabolismo , Linoleoil-CoA Desaturase/genética , Linoleoil-CoA Desaturase/metabolismo , Metabolismo dos Lipídeos/genética , Fígado/efeitos dos fármacos , Fígado/crescimento & desenvolvimento , Fígado/metabolismo , Músculos/efeitos dos fármacos , Músculos/metabolismo , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Nucleobindinas , Especificidade de Órgãos , Perciformes/crescimento & desenvolvimento , Perciformes/metabolismo , Hipófise/efeitos dos fármacos , Hipófise/crescimento & desenvolvimento , Hipófise/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , SalinidadeRESUMO
In mammals and fish, somatic growth and metabolism are coordinated by the GH-IGF axis, composed of growth hormone (GH), growth hormone receptors I and II (GHR-I and GHR-II), and the insulin-like growth factors I and II (IGF-I and IGF-II). In order to determine if dietary macronutrients regulate the hepatopancreatic expression of ghr-I, ghr-II, igf-I and igf-II independently of circulating GH, organ culture experiments were conducted. Briefly, goldfish hepatopancreas sections were incubated with different doses of glucose; L-tryptophan; oleic acid; linolenic acid (LNA); eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). After two and four hours of treatment, the expression of ghr-I, ghr-II, igf-I and igf-II mRNAs was quantified. We found that glucose and L-tryptophan globally upregulate the mRNA expression of ghr-I; ghr-II; igf-I and igf-II. Duration of exposure, and unsaturation level of fatty acids differentially modulate ghr-I, ghr-II and igf-II mRNA expression. Additionally, we found that fatty acids increase the expression of igf-I depending on incubation time and fatty acid class. In conclusion, here we present evidence for GH-independent, direct effects exerted by dietary macronutrients on GHR and IGF in goldfish hepatopancreas.