“In vivo” effects of insulin on carbohydrate metabolism of catfish (Ictalurus melas)

Ottolenghi, C; Puviani, A.C.; Baruffaldi, A.; Brighenti, L

doi:10.1016/0300-9629(82)90007-x

Cited by 25 publications

(12 citation statements)

References 23 publications

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“…The enhanced transcript levels for key enzymes (FAS and G6PDH) and transcriptional factors involved in lipogenesis (SREBP-1c-like) support an increased lipogenic potential as previously reported in trout, with insulin and glucose as major regulators (Cowley and Sheridan, 1993;Polakof et al, 2009). The increased glycogen levels previously reported in catfish (Ottolenghi et al, 1982), and the decreased G6Pase mRNA levels shown here, further support the idea that insulin is stimulating glycogen deposition and depressing glucose export to the blood, thus preventing the hyperglycemia observed in the saline-control group. These results are further supported by the report that the repression of the G6Pase1 gene by glucose is overcome by insulin (Polakof et al, 2009); thus, it is not surprising that the poor inhibition of the G6Pase gene in trout fed carbohydrates (Panserat et al, 2001a) could be increased by the addition of insulin, improving glycemic control in insulin-infused trout.…”

Section: Insulin Improves Glycemia After Feeding One High-carbohydratsupporting

confidence: 89%

“…These results are similar to those found by Sundby et al in Atlantic salmon fed with a diet containing 19% carbohydrates and receiving a single insulin administration (Sundby et al, 1991c), even though plasma insulin (exogenous) levels were higher than in the present study. Other studies reported similar results, but comparisons are often difficult as the diets used contained a lower carbohydrate content (~5%), or the insulin dose was pharmacological and the animal model different (omnivorous species) (Ottolenghi et al, 1982). Trout with insulin pumps for 30h displayed liver changes that help to explain the lower glycemia exhibited in these fish compared with the saline-control group.…”

Section: Insulin Improves Glycemia After Feeding One High-carbohydratmentioning

confidence: 82%

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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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Section: Insulin Improves Glycemia After Feeding One High-carbohydratsupporting

confidence: 89%

Section: Insulin Improves Glycemia After Feeding One High-carbohydratmentioning

confidence: 82%

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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“…This increased storage of glucose as glycogen after insulin administration was previously reported in several fish species (Bhatt et al, 1980;Emdin, 1982;Ottolenghi et al, 1982) and could be related to the changes in Akt protein found in skeletal muscle. After insulin injection we detected not only more active (phosphorylated) Akt but also more total Akt protein, probably resulting in a greater magnitude of insulinstimulated signal (Gosmanov et al, 2004), allowing a faster and stronger response of the muscle to the hormone stimulation.…”

Section: Acute Insulin Administration: Metabolic Regulation In Musclesupporting

confidence: 74%

“…Regarding glucose uptake, in addition to GLUT4 (glucose transporter type 4) translocation to the plasma membrane in response to insulin in fish skeletal muscle (Díaz et al, 2007), both GLUT1 (glucose transporter type 1) and GLUT4 gene expression are regulated by this hormone in vivo and in vitro (Capilla et al, 2002;Díaz et al, 2009). On the other hand, although insulin administration often results in unspecific glycogen fluctuations (Mommsen and Plisetskaya, 1991), the most common response is the depletion of hepatic glycogen stores in vivo (Bhatt et al, 1980;Ottolenghi et al, 1982), while a more consistent glycogenic response is found in vitro (Foster and Moon, 1990;Ottolenghi et al, 1981). The response of muscle glycogen to insulin administration seems to be more consistent, as in several fish species muscle glycogen levels increase following physiological hormone injection (Bhatt et al, 1980;Ottolenghi et al, 1982).…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, although insulin administration often results in unspecific glycogen fluctuations (Mommsen and Plisetskaya, 1991), the most common response is the depletion of hepatic glycogen stores in vivo (Bhatt et al, 1980;Ottolenghi et al, 1982), while a more consistent glycogenic response is found in vitro (Foster and Moon, 1990;Ottolenghi et al, 1981). The response of muscle glycogen to insulin administration seems to be more consistent, as in several fish species muscle glycogen levels increase following physiological hormone injection (Bhatt et al, 1980;Ottolenghi et al, 1982). Concurrent with its action on glucose uptake, insulin depresses the rate of gluconeogenesis in some salmonids (De la Higuera and Cárdenas, 1986), but not in other fish species (Mommsen and Plisetskaya, 1991).…”

Section: Introductionmentioning

confidence: 99%

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Insulin-induced hypoglycaemia is co-ordinately regulated by liver and muscle during acute and chronic insulin stimulation in rainbow trout (Oncorhynchus mykiss)

Polakof

Skiba‐Cassy

Choubert

et al. 2010

Journal of Experimental Biology

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SUMMARYThe relative glucose intolerance of carnivorous fish species is often proposed to be a result of poor peripheral insulin action or possibly insulin resistance. In the present study, data from aortic cannulated rainbow trout receiving bovine insulin (75 mIU kg -1 ) injections show for the first time their ability to clear glucose in a very efficient manner. In another set of experiments, mRNA transcripts and protein phosphorylation status of proteins controlling glycaemia and glucose-related metabolism were studied during both acute and chronic treatment with bovine insulin. Our results show that fasted rainbow trout are well adapted at the molecular level to respond to increases in circulating insulin levels, and that this hormone is able to potentially improve glucose distribution and uptake by peripheral tissues. After acute insulin administration we found that to counter-regulate the insulininduced hypoglycaemia, trout metabolism is strongly modified. This short-term, efficient response to hypoglycaemia includes a rapid, coordinated response involving the reorganization of muscle and liver metabolism. During chronic insulin treatment some of the functions traditionally attributed to insulin actions in mammals were observed, including increased mRNA levels of glucose transporters and glycogen storage (primarily in the muscle) as well as decreased mRNA levels of enzymes involved in de novo glucose production (in the liver). Finally, we show that the rainbow trout demonstrates most of the classic metabolic adjustments employed by mammals to efficiently utilize glucose in the appropriate insulin context.

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Effects of diet and feeding time on daily variations in plasma insulin, hepatic c-AMP and other metabolites in a teleost fish,Dicentrarchus labrax L.

González

Zanuy

Carrillo

1988

Fish Physiol Biochem

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Juvenile sea bass, 1.5 years old, of mixed sex, held on long photoperiods were fed early on the photoperiod and late on the photoperiod, using different diets. Fish fed natural diets showed a daily rhythmicity of plasma insulin, liver c-AMP, plasma glucose, liver glycogen and muscle glycogen content, however, fish fed a commercial diet did not show this daily rhythmicity except for plasma insulin levels. In addition, these fish had significantly lower levels of plasma insulin, liver c-AMP and plasma glycerol than the group fed on the natural diets at similar feeding times. The time of feeding also induced different rhythmicity patterns in hormones and metabolites as well as a significant change in their mean levels. These facts are discussed in relation with the pre-feeding activity and increased appetite exhibited by the fish fed late on the photoperiod and with their implications on fish culture.

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“In vivo” effects of insulin on carbohydrate metabolism of catfish (Ictalurus melas)

Cited by 25 publications

References 23 publications

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

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

Insulin-induced hypoglycaemia is co-ordinately regulated by liver and muscle during acute and chronic insulin stimulation in rainbow trout (Oncorhynchus mykiss)

Effects of diet and feeding time on daily variations in plasma insulin, hepatic c-AMP and other metabolites in a teleost fish,Dicentrarchus labrax L.

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