Glucose, amino acids and fatty acids directly regulate ghrelin and NUCB2/nesfatin-1 in the intestine and hepatopancreas of goldfish (Carassius auratus) in vitro.
Bertucci, J. I., Blanco, A. M., Canosa, L. F. and Unniappan, S.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico Chascomus. Av. Intendente Marino Km 8,200, CC 164 (7130), Chascomus, Prov. de Buenos Aires, Argentina. Electronic address: jbertucci@intech.gov.ar.
Departamento de Fisiologia (Fisiologia Animal II), Facultad de Biologia, Universidad Complutense de Madrid. Calle Jose Antonio Novais 12, 28040, Madrid, Spain. Electronic address: ayelenmelisablanco@ucm.es.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico Chascomus. Av. Intendente Marino Km 8,200, CC 164 (7130), Chascomus, Prov. de Buenos Aires, Argentina. Electronic address: lcanosa@intech.gov.ar.
Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, S7N 5B4, Canada. Electronic address: suraj.unniappan@usask.ca.
Ghrelin and nesfatin-1 are two peptidyl hormones primarily involved in food intake regulation. We previously reported that the amount of dietary carbohydrates, protein and lipids modulates the expression of these peptides in goldfish in vivo. In the present work, we aimed to characterize the effects of single nutrients on ghrelin and nesfatin-1 in the intestine and hepatopancreas. First, immunolocalization of ghrelin and NUCB2/nesfatin-1 in goldfish hepatopancreas cells was studied by immunohistochemistry. Second, the effects of 2 and 4hour-long exposures of cultured intestine and hepatopancreas sections to glucose, l-tryptophan, oleic acid, linolenic acid (LNA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on ghrelin and nesfatin-1 gene and protein expression were studied. Co-localization of ghrelin and NUCB2/nesfatin-1 in the cytoplasm of goldfish hepatocytes was found. Exposure to glucose led to an upregulation of preproghrelin and a downregulation of nucb2/nesfatin-1 in the intestine. l-Tryptophan mainly decreased the expression of both peptides in the intestine and hepatopancreas. Fatty acids, in general, downregulated NUCB2/nesfatin-1 in the intestine, but only the longer and highly unsaturated fatty acids inhibited preproghrelin. EPA exposure led to a decrease in preproghrelin, and an increase in nucb2/nesfatin-1 expression in hepatopancreas after 2h. These results show that macronutrients exert a dose- and time-dependent, direct regulation of ghrelin and nesfatin-1 in the intestine and hepatopancreas, and suggest a role for these hormones in the digestive process and nutrient metabolism.
Comparative Biochemistry and Physiology. Part A: Molecular and Integrative Physiology 206: 24-35 (2017)