Direct actions of macronutrient components on goldfish hepatopancreas in vitro to modulate the expression of ghr-I, ghr-II, igf-I and igf-II mRNAs.
Bertucci, J. I., Blanco, A. M., Canosa, L. F. and Unniappan, S.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico Chascomus, Buenos Aires, Argentina.
Departamento de Fisiologia (Fisiologia Animal II), Facultad de Biologia, Universidad Complutense de Madrid, Madrid, Spain.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico Chascomus, 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, Saskatoon, Saskatchewan, Canada. Electronic address: suraj.unniappan@usask.ca.
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.
General and Comparative Endocrinology 250: 1-8 (2017)