Teleost fishes represent a highly diverse group consisting of more than 20,000 species living across all aquatic environments. This group has significant economical, societal and environmental impacts, yet research efforts have concentrated primarily on salmonid and cyprinid species. This review examines carbohydrate/glucose metabolism and its regulation in these model species including the role of hormones and diet. Over the past decade, molecular tools have been used to address some of the downstream components of these processes and these are incorporated to better understand the roles played by carbohydrates and their regulatory paths. Glucose metabolism remains a contentious area as many fish species are traditionally considered glucose intolerant and, therefore, one might expect that the use and storage of glucose would be considered of minor importance. However, the actual picture is not so clear since the apparent intolerance of fish to carbohydrates is not evident in herbivorous and omnivorous species and even in carnivorous species, glucose is important for specific tissues and/or for specific activities. Thus, our aim is to up-date carbohydrate metabolism in fish, placing it to the context of these new experimental tools and its relationship to dietary intake. Finally, we suggest that new research directions ultimately will lead to a better understanding of these processes.

Glucose metabolism in fish: a review

The insulin-like growth factor (IGF) system plays a central role in the neuroendocrine regulation of growth in all vertebrates. Evidence from studies in a variety of vertebrate species suggest that this growth factor complex, composed of ligands, receptors, and high-affinity binding proteins, evolved early during vertebrate evolution. Among nonmammalian vertebrates, IGF signaling has been studied most extensively in fish, particularly teleosts of commercial importance. The unique life history characteristics associated with their primarily aquatic existence has fortuitously led to the identification of novel functions of the IGF system that are not evident from studies in mammals and other tetrapod vertebrates. Furthermore, the emergence of the zebrafish as a preferred model for development genetics has spawned progress in determining the requirements for IGF signaling during vertebrate embryonic development. This review is intended as a summary of our understanding of IGF signaling, as revealed through research into the expression, function, and evolution of IGF ligands, receptors, and binding proteins in fish.

Insulin-like growth factor signaling in fish.

Growth hormone and insulin-like growth factors in fish: where we are and where to go.

Utilisation of dietary carbohydrates in farmed fishes: New insights on influencing factors, biological limitations and future strategies

This communication summarizes viewpoints, discussion, perspectives, and questions, put forward at a workshop on “Growthhormone and insulin-like growth factors in Wsh” held on September 7th, 2004, at the 5th International Symposium on Fish Endocri-nology in Castellon, Spain. 2005 Elsevier Inc. All rights reserved. Keywords: Growth Hormone and insulin -like growth factors in Wsh 1. Growth hormone Growth hormone (GH) is a pluripotent hormone pro-duced by the pituitary gland in teleosts as in other verte-brates. GH brings about its action by binding to a singlepass-transmembrane receptor, the GH receptor (GHR),in target tissue. Ligand binding induces receptor dimer-ization producing an active trimeric complex (for review,see Perez-Sanchez et al., 2002). GH has been sequencedand/or the protein isolated from scores of teleosts, vari-ous immunoassays established, and a number of GH-transgenic Wsh strains established. Over the last twodecades, many aspects of GH physiology have been thesubject of intense research in Wsh such as the salmonids,cyprinids, and sparids. In Wsh, GH participates in almostall major physiological processes in the body includingthe regulation of ionic and osmotic balance, lipid, pro-tein, and carbohydrate metabolism, skeletal and soft tis-sue growth, reproduction and immune function. Recentstudies have indicated that GH aVects several aspects ofbehaviour, including appetite, foraging behaviour,aggression, and predator avoidance, which in turn hasecological consequences (for reviews, see Bjornsson,1997; Bjornsson et al., 2004; Perez-Sanchez, 2000; Peterand Marchant, 1995).Despite the vast body of knowledge which exists doc-umenting GH action in teleost Wsh, the mode of GHaction remains a major discussion topic (for review, seeBjornsson et al., 2004). Generalized claims have beenmade that most/all GH eVects are indirect, based on anoutdated mammalian view where the pituitary/hepaticGH/IGF-I system was seen as an “axis” with IGF-Imediating the physiological action of GH (for review,see Bjornsson et al., 2004; Butler and Le Roith, 2001).

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Growth hormone and insulin-like growth factors in Wsh: Where we are and where to go

The relative function of IGF-I and insulin on fish muscle metabolism and growth has been investigated by the isolation and culture at different stages (myoblasts at day 1, myocytes at day 4, and my...

https://www.physiology.org/doi/pdf/10.1152/ajpregu.00459.2003

Metabolic and mitogenic effects of IGF-I and insulin on muscle cells of rainbow trout.

Six new dinuclear complexes obtained by reaction oftrans-[CrF(H2O)(pn)2](ClO4) (pn=1,2-diaminopropane) and [M(CN)4]2− (M=Ni, Pd or Pt), [Co(CN)6]3−, [Cr(CN)6]3− and [CrNO(CN)5]3− have been isolated. They have been characterised by chemical analysis, electronic and i.r. spectra and conductivity measurements. In order to compare the behaviour of these compounds with the ethylenediamine(en) and 1,3-diaminopropane (tn) analogues, previously described, the new compoundscis-[CrFX(pn)2]X (X=Cl, Br or I) have been also obtained and characterised. The derivatives of the anion [Pt(CN)4]2− show Pt-Pt interactions in both the solid state and in solution.

María Laura Martínez

Papers

Metabolic and mitogenic effects of IGF-I and insulin on muscle cells of rainbow trout.

Dinuclear complexes with a μ-cyano-ligand. — Part VII. Synthesis and characterization of several derivatives oftrans-[CrF(H2O)(1,2-diaminopropane)2]2+