Plasma levels of insulin, glucagon and glucagon-like peptide in salmonids of different weights

Sundby, Anne; Eliassen, Knut Arnet; Refstie, Terje; Plisetskaya, Erika M.

doi:10.1007/bf02265143

Cited by 43 publications

(17 citation statements)

References 19 publications

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“…Plasma levels of insulin in one-and two-year old Atlantic salmon, kept in fresh water during the period of parr-smolt transformation, were in the same range as previously reported values for salmonids, including one-year old farmed Atlantic salmon at the west coast of the U.S.A. (Plisetskaya et al 1994a), immature Atlantic salmon (Sundby et al 1991) and coho salmon during the period of parr-smolt transformation (Plisetskaya et al 1988; i 4 ab I 7 7…”

Section: Discussionsupporting

confidence: 69%

“…However, absolute values of plasma insulin, even measured by homologous radioimmunoassay, are not very informative by themselves because they may result from a number of processes, such as insulin synthesis, secretion, binding to the target tissues, clearance rates etc. It is known that most often these values reflect the nutritional status of the fish (reviewed by Mommsen and Plisetskaya 1991), and may be correlated to fish weight, so that the larger fish have higher plasma insulin titers (Sundby et al 1991). In the present study, the one-year Atlantic salmon were considerably smaller in 1992 than in 1990.…”

Section: Discussionmentioning

confidence: 99%

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Plasma levels of insulin and liver glycogen contents in one- and two-year old Atlantic salmon (Salmo salar L.) during the period of parr-smolt transformation

Mayer

Borg

Plisetskaya

1994

Fish Physiol Biochem

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Plasma levels of insulin were measured by specific radioimmunoassay in 1-year and 2-year old Atlantic salmon (Salmo salar) parr during the period of parr-smolt transformation. The two-year old fish were of two different categories; silvering pre-smolts and previously mature male parr. If insulin plays an important role in parr-smolt transformation and/or subsequent osmoregulatory changes it was expected that the pre-smolts would show a different insulin profile compared to the mature male parr and one-year old parr, both of which show impaired hypoosmoregulatory ability compared to smolts. Measurements were taken during two separate years. Between January and April both categories of two-year old fish had generally higher plasma levels of insulin compared to the non-smolting one-year old parr. In the pre-smolts insulin levels ranged from 4.0 to 7.9 ng ml(-1), and from 7.8 to 16.7 ng ml(-1) in 1990 and 1992 respectively, while in the previously mature males the same respective values were from 4.3 to 10.0 ng ml(-1), and from 6.6 to 24.1 ng ml(-1). In the two-year old fish, whether pre-smolts or mature males, plasma insulin levels peaked between 1-2 months before final smoltification, after which insulin titers declined sharply. In 1990, the 1-year old parr showed a dual peak in plasma insulin. Insulin first peaked in February (7.8 ng ml(-1)), and then again in April-May (7.7 ng ml(-1)), while in 1992 the 1-year old parr showed a number of smaller transient peaks (5-7 ng ml(-1)) between March-May, followed by sharp elevation of insulin levels in June. Liver glycogen contents were at their highest (3.5-5.0 g 100 g(-1) I liver wet weight) in March in both 1-year and 2-year old fish. Glycogen levels were low during the later stages of parr-smolt transformation, before rising again in June in both the 1-year old and precociously mature parr, but not in the smolts.

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Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Plasma levels of insulin and liver glycogen contents in one- and two-year old Atlantic salmon (Salmo salar L.) during the period of parr-smolt transformation

Mayer

Borg

Plisetskaya

1994

Fish Physiol Biochem

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“…1, Table 2). Insulin stimulates amino acid uptake and protein synthesis especially in the muscle tissues (Murat et al 1981;Matty 1986), and thereby exerting a growth promoting effect in salmonids (Donaldson et al 1979;Ablett et al 1981;Sundby et al 1991;Rungruangsak-Torrissen et al 1999a). Moreover, the profiles of trypsin expression as well as chymotrypsin expression (Fig.…”

Section: Discussionmentioning

confidence: 95%

Digestive efficiency, free amino acid pools and quality of growth performance in Atlantic salmon (Salmo salar L.) affected by light regimes and vaccine types

Rungruangsak‐Torrissen

Sunde

Berg

et al. 2008

Fish Physiol Biochem

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This study comprised the results of three different seawater trials using unique combination of techniques to study protease digestive efficiency and growth performance quality to illustrate the effects of light regimes and vaccine types in Atlantic salmon (Salmo salar L.). Fish with higher growth had higher trypsin (T) and chymotrypsin (C) specific activities with higher T/C ratio or slope T/C ratio [calculated from the regression between trypsin (y) and chymotrypsin (x) specific activities] in the pyloric caeca. The T/C ratios indicated fish growth rates over a period of 1-2 months, while the slope T/C ratios indicated fish growth rates at sampling. Adaptation period for adjustment to the new environment of continuous light was 70 days, indicated by the differences in trypsin specific activities and the crossing of slope T/C ratio regressions following with the changes in growth rate directions between the control and the treated group. Vaccine types affected fish vertebral growth, and additional continuous light enhanced the impact of vaccines on fish growth during springtime, indicated by differences in slope T/C ratios. Continuous light stimulated fish growth during winter to spring, when the natural day length was short, without significantly changing white muscle and oocyte qualities in the fish of about 500 g, except for significantly increased white muscle RNA concentration. Continuous light also reduced fish growth rate later during summer, when the natural day length was long, by precedently decreasing the T/C ratio in late spring. Interestingly, plasma levels of free lysine related to tryptic digestion were correlated with trypsin specific activity levels. Continuous light caused higher levels of most free amino acids (FAA) involved in nitrogen metabolism, higher incorporation of essential FAA for protein synthesis, and higher protein turnover rate (free hydroxyproline levels) in both plasma and white muscle. However, continuous light did not affect higher protein content, intracellular buffering capacity and RNA levels in the white muscle of the fish of about 1 kg, probably due to limitation of FAA available for protein synthesis. It is therefore suggested that enhancing fish growth by continuous light stimulation should be accompanied by increasing availability or content of dietary protein (and probably minerals), which in turn would improve the quality of fish growth performance through increasing fillet protein concentration, strengthening vertebral growth, and delaying oocyte development.

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“…Thus, in the present study insulin was delivered at a constant rate using implanted pumps while the trout were fed for 1 or 5 days with a carbohydrate-enriched diet to determine whether exogenous insulin could improve glycemia in this 'glucose-intolerant' species. Bovine insulin levels were estimated at 6ngml -1 across all trout implanted with pumps containing insulin; these circulating insulin values are relatively low when compared with trout plasma insulin values estimated by the partly homologous RIA analysis (bonito) (Capilla et al, 2003;Novoa et al, 2004), but within the physiological range when compared with fully homologous RIA analysis (salmon) (Sundby et al, 1991a;Sundby et al, 1991b). …”

Section: Discussionmentioning

confidence: 99%

“…Insulin functions primarily as an anabolic hormone by stimulating postprandial glucose uptake by liver and skeletal muscle, depressing rates of hepatic gluconeogenesis, and activating glycogenesis and lipogenesis. However, the fact that some carnivorous species remained 'glucose intolerant', even when insulin was effectively secreted (Moon, 2001), and that insulin levels correlate with fish mass (Sundby et al, 1991b) suggests also that this hormone can have an important role on fish growth and development (Mommsen and Plisetskaya, 1991). In fish, although the most prominent response to exogenous insulin injection is hypoglycemia (Ince, 1983), both the magnitude and duration of this effect are dependent on insulin type and dose, the route of injection, the season, nutritional state and previous nutritional history (Ince, 1983;Mommsen and Plisetskaya, 1991).…”

Section: Introductionmentioning

confidence: 99%

Effects of insulin infusion on glucose homeostasis and glucose metabolism in rainbow trout fed a high-carbohydrate diet

Polakof

Moon

Aguirre

et al. 2010

Journal of Experimental Biology

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SUMMARYThe origin for the poor glucose utilization in carnivorous fish species fed high carbohydrate diets remains under debate. In the present study, we have fed rainbow trout a diet containing 30% carbohydrate for 1 or 5 days. In both cases, fish were implanted with mini-osmotic pumps releasing 0.7i.u.kg -1 day -1 bovine insulin, and mRNA transcripts and the protein phosphorylation status of proteins controlling glycemia and glucose-related metabolism were studied in fish killed 6h after the last meal. We demonstrate that when the exposure occurs over a short term (30h), insulin exerts beneficial actions on trout glucose homeostasis, including a lowered glycemia and increased hepatic lipogenic and glycogenic potentials. However, when trout were fed for 5 days, these beneficial actions of insulin infusion were no longer observed. Thus, the increased lipogenic potential observed after one single meal was not present, and this together with the increased glycogenesis and the decreased glucose exported to the blood from the liver explains the lack of hypoglycemic action of insulin. The fact that insulin improved glucose homeostasis when administrated over a short time period implies that endogenous insulin secretion is inadequate in trout to deal with this amount of dietary carbohydrates. Moreover, the fact that a longer exposure to insulin resulted in a reduced response indicates that the rainbow trout is sensitive to insulin, re-enforcing the hypothesis that the hyperglycemia observed following a high carbohydrate meal is an insulin secretion issue rather an insulin action issue.Key words: insulin, fish, dietary carbohydrate, glucose utilization, glucose metabolism. THE JOURNAL OF EXPERIMENTAL BIOLOGY 4152related to a problem of either insulin secretion or insulin action. Therefore, the objectives of the present study on the carnivorous rainbow trout were: (1) to study the metabolic effects of continuous exogenous insulin infusion in fish fed with a high carbohydrate diet for one (test meal) or 5 days; and (2) to evaluate the ability of insulin to improve trout glycemic control when fed with a high carbohydrate diet. In addition, for the first time the three main insulin targets, skeletal muscle, white adipose tissue (WAT) and liver, were studied at both the biochemical and the molecular levels to analyze the potential molecular origins of the plasma glucose profiles observed in fish fed with a high carbohydrate diet. Thus, glycemia, glycogen levels and the mRNA levels of the main proteins involved in glucose metabolism were studied in liver, skeletal muscle and WAT. MATERIALS AND METHODS FishImmature rainbow trout (Oncorhynchus mykiss Walbaum) were obtained from the INRA experimental fish farm facilities of Donzacq (Landes, France). Fish were maintained in tanks kept in open circuits with 17°C well-aerated water and a controlled photoperiod (light:dark 12h:12h), and were fed with a standard trout commercial diet during the acclimation period (T-3P classic, Trouw, France). Experimental protocolsFor susta...

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Plasma levels of insulin, glucagon and glucagon-like peptide in salmonids of different weights

Cited by 43 publications

References 19 publications

Plasma levels of insulin and liver glycogen contents in one- and two-year old Atlantic salmon (Salmo salar L.) during the period of parr-smolt transformation

Plasma levels of insulin and liver glycogen contents in one- and two-year old Atlantic salmon (Salmo salar L.) during the period of parr-smolt transformation

Digestive efficiency, free amino acid pools and quality of growth performance in Atlantic salmon (Salmo salar L.) affected by light regimes and vaccine types

Effects of insulin infusion on glucose homeostasis and glucose metabolism in rainbow trout fed a high-carbohydrate diet

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