Ketone Body Metabolism in the Carp Cyprinus carpio: Biochemical and 1H NMR Spectroscopical Analysis

Segner, Helmut; Dölle, Andreas; Böhm, R.

doi:10.1016/s0305-0491(96)00213-1

Cited by 33 publications

(19 citation statements)

References 25 publications

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“…Finally, the maintained FBPase activity in the liver of starved dentex with respect to controls supports the important role of this process in the maintenance of plasma glucose levels during prolonged food deprivation in fish (Navarro and Gutiérrez 1995). Previous studies also reported such maintained gluconeogenic capacity in other starved fish such as Atlantic salmon, S. salar (Soengas et al 1996), carp, C. carpio (Segner et al 1997), and trout, O. mykiss (Kirchner et al 2005), whereas an enhanced FBPase activity in starved gilthead sea bream, S. aurata, has been reported (Metón et al 2003;Sangiao-Alvarellos et al 2005). Although amino acids derived from protein hydrolysis may be important precursors for glucose synthesis under such circumstances (Suárez and Mommsen 1987), the inhibition of ALAT activity in liver seems to reflect a reduced use of this important glucogenic amino acid.…”

Section: Liversupporting

confidence: 75%

Metabolic adjustments of Dentex dentex to prolonged starvation and refeeding

Pérez‐Jiménez

Cardenete

Hidalgo

et al. 2012

Fish Physiol Biochem

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The particular metabolic strategies of the common dentex (Dentex dentex) to face a period of prolonged starvation and subsequent refeeding were assessed. Plasma metabolites, endogenous reserves, and the activity of key enzymes of intermediary metabolism in liver, white muscle, and heart were evaluated. Plasma glucose, total lipid, triglycerides, total-, HDL- and LDL-cholesterol, and protein levels, liver, and white muscle glycogen, and perivisceral, and muscle fat were significantly reduced by starvation, whereas liver lipid content was surprisingly increased. Those enzymes involved in phosphorylation and oxidation of glucose and lipid synthesis, as well as alanine aminotransferase activity, were significantly depressed in liver of starved fish. The increase in β-hydroxyacyl-CoA dehydrogenase (HOAD) indicated an enhanced fatty acid oxidation during starvation. Part of the acetyl-CoA generated by β-oxidation was oxidized in the hepatic Krebs cycle, as reflected the increased citrate synthase (CS) activity. The oxaloacetate required for the reaction catalized by CS activity would be supplied by aspartate aminotransferase (ASAT) activity whose activity was also enhanced. Glutamate dehydrogenase also increased to deaminate the glutamate produced by transaminases, especially by the increased ASAT activity. Liver gluconeogenesis of starved fish was maintained at the same rate that in controls, with glycerol playing an important role as glucogenic substrate. The increased hepatic β-hydroxybutyrate dehydrogenase (β-OHBDH) activity indicates that part of the acetyl-CoA arriving from β-oxidation was being diverted for ketone bodies production with dentex liver playing an important role in providing ketone bodies as fuels for other tissues under such circumstances. Most enzyme activities in white muscle of starved dentex were significantly depressed. In heart, starvation induced an important inhibition of those enzymes involved in glucose and protein metabolism, whereas CS, HOAD, and β-OHBDH activities were maintained at control levels. Although several biomarkers assayed returned to control values after refeeding, many others did not, which indicate that after 3 weeks of refeeding, pre-starved dentex is still experiencing a transient period of metabolic adjustments directed toward the restoration of body mass.

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Section: Liversupporting

confidence: 75%

Metabolic adjustments of Dentex dentex to prolonged starvation and refeeding

Pérez‐Jiménez

Cardenete

Hidalgo

et al. 2012

Fish Physiol Biochem

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“…Plasma levels of β-hydroxybutyrate actually decreased with fasting for the salmon S. salar (518). Given the apparent lack of a ketone response with fasting among lung and teleost fishes, ketones apparently contribute little to fueling their metabolism (or to preserving proteins) during episodes of fasting (42,190,397,501,518,601).…”

Section: Ketone Bodiesmentioning

confidence: 98%

“…The livers of these fish (primary site of ketone synthesis) similarly lacked any change with estivation in the activities of the ketone-synthesizing enzymes β-hydroxybutyrate dehydrogenase (β-HBDH) and succinyl-CoA ketotransferase (190). Fasts of 60 days and up to 150 days, respectively, for the carp C. carpio and sea bass D. labrax generated no change in plasma concentrations of acetoacetate and no detection of β-hydroxybutyrate (501,601). Plasma levels of β-hydroxybutyrate actually decreased with fasting for the salmon S. salar (518).…”

Section: Ketone Bodiesmentioning

confidence: 99%

Integrative Physiology of Fasting

Secor

Carey

2016

Comprehensive Physiology

150

144

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Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting.

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“…During acute seawater (SW) acclimation, these animals overcome an increase in plasma osmolality of as much as 175 mOsm through active excretion of ions, consuming 20-68% of their total metabolic energy demand (Morgan et al 1997, Boeuf & Payan 2001. The primary site of ion exchange is the gill (Evans et al 2005), which has a low capacity for the oxidation of fatty acids or ketones (Segner et al 1997, Crockett et al 1999. Gill ionocytes utilize glucose from adjacent glycogen-rich cells , and collectively the gill may represent only a fraction (3-8%) of the energy demand (Morgan & Iwama 1999), suggesting that other tissues contribute to the bulk of the expenditure (e.g.…”

Section: Introductionmentioning

confidence: 99%

Role for leptin in promoting glucose mobilization during acute hyperosmotic stress in teleost fishes

Baltzegar

Reading

Douros

et al. 2013

Journal of Endocrinology

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Osmoregulation is critical for survival in all vertebrates, yet the endocrine regulation of this metabolically expensive process is not fully understood. Specifically, the function of leptin in the regulation of energy expenditure in fishes, and among ectotherms, in general, remains unresolved. In this study, we examined the effects of acute salinity transfer (72 h) and the effects of leptin and cortisol on plasma metabolites and hepatic energy reserves in the euryhaline fish, the tilapia (Oreochromis mossambicus). Transfer to 2/3 seawater (23 ppt) significantly increased plasma glucose, amino acid, and lactate levels relative to those in the control fish. Plasma glucose levels were positively correlated with amino acid levels (R 2 Z0.614), but not with lactate levels. The mRNA expression of liver leptin A (lepa), leptin receptor (lepr), and hormone-sensitive and lipoprotein lipases (hsl and lpl) as well as triglyceride content increased during salinity transfer, but plasma free fatty acid and triglyceride levels remained unchanged. Both leptin and cortisol significantly increased plasma glucose levels in vivo, but only leptin decreased liver glycogen levels. Leptin decreased the expression of liver hsl and lpl mRNAs, whereas cortisol significantly increased the expression of these lipases. These findings suggest that hepatic glucose mobilization into the blood following an acute salinity challenge involves both glycogenolysis, induced by leptin, and subsequent gluconeogenesis of free amino acids. This is the first study to report that teleost leptin A has actions that are functionally distinct from those described in mammals acting as a potent hyperglycemic factor during osmotic stress, possibly in synergism with cortisol. These results suggest that the function of leptin may have diverged during the evolution of vertebrates, possibly reflecting differences in metabolic regulation between poikilotherms and homeotherms.

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Ketone Body Metabolism in the Carp Cyprinus carpio: Biochemical and 1H NMR Spectroscopical Analysis

Cited by 33 publications

References 25 publications

Metabolic adjustments of Dentex dentex to prolonged starvation and refeeding

Metabolic adjustments of Dentex dentex to prolonged starvation and refeeding

Integrative Physiology of Fasting

Role for leptin in promoting glucose mobilization during acute hyperosmotic stress in teleost fishes

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