The Enzymatic and Metabolic Effects of Extended Food Deprivation in Rana pipiens

Blier, Pierre; Guderley, Helga

doi:10.1086/physzool.59.2.30156037

Cited by 6 publications

(6 citation statements)

References 29 publications

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“…The starvation-induced decrease in glycolytic enzymatic capacity, especially HK, in cuttlefish tissues is similar to the well-established, rapid (days) downregulation of glycolysis in starved mammals (Cherel et al 1988;Pilkis et al 1988;Gibson and Harris 2002) and certain other vertebrates (Moon and Johnston 1980;Blier and Guderley 1986;Foster and Moon 1991;Metón et al 1999;Secor and Carey 2016). The time scale of the response in cuttlefish, with significant decreases generally occurring only after long-starvation, suggests that circulating glucose is used as fuel early in starvation but later conserved for essential tissues (e.g.…”

Section: Starvation Responses: Glycolytic Capacity Is Downregulated Wsupporting

confidence: 66%

Enzymatic capacities of metabolic fuel use in cuttlefish (Sepia officinalis) and responses to food deprivation: insight into the metabolic organization and starvation survival strategy of cephalopods

et al. 2016

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Food limitation is a common challenge for animals. Cephalopods are sensitive to starvation because of high metabolic rates and growth rates related to their "live fast, die young" life history. We investigated how enzymatic capacities of key metabolic pathways are modulated during starvation in the common cuttlefish (Sepia officinalis) to gain insight into the metabolic organization of cephalopods and their strategies for coping with food limitation. In particular, lipids have traditionally been considered unimportant fuels in cephalopods, yet, puzzlingly, many species (including cuttlefish) mobilize the lipid stores in their digestive gland during starvation. Using a comprehensive multi-tissue assay of enzymatic capacities for energy metabolism, we show that, during long-term starvation (12 days), glycolytic capacity for glucose use is decreased in cuttlefish tissues, while capacities for use of lipid-based fuels (fatty acids and ketone bodies) and amino acid fuels are retained or increased. Specifically, the capacity to use the ketone body acetoacetate as fuel is widespread across tissues and gill has a previously unrecognized capacity for fatty acid catabolism, albeit at low rates. The capacity for de novo glucose synthesis (gluconeogenesis), important for glucose homeostasis, likely is restricted to the digestive gland, contrary to previous reports of widespread gluconeogenesis among cephalopod tissues. Short-term starvation (3-5 days) had few effects on enzymatic capacities. Similar to vertebrates, lipid-based fuels, putatively mobilized from fat stores in the digestive gland, appear to be important energy sources for cephalopods, especially during starvation when glycolytic capacity is decreased perhaps to conserve available glucose.

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Section: Starvation Responses: Glycolytic Capacity Is Downregulated Wsupporting

confidence: 66%

Enzymatic capacities of metabolic fuel use in cuttlefish (Sepia officinalis) and responses to food deprivation: insight into the metabolic organization and starvation survival strategy of cephalopods

et al. 2016

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“…Frogs accumulate glycogen with the onset of cold weather (Pasanen and Koskela, 1974;Smith, 1950). However, this requires that the appropriate cue, low temperature, is present and that food is still available from which glycogen reserves can be created (Blier and Guderley, 1986). In the previous studies of gray treefrogs, all of the animals were 'step-acclimated'.…”

Section: Table·2 Survival Of Gray Treefrogs Of Both Species and Frommentioning

confidence: 99%

Geographic variation in energy storage and physiological responses to freezing in the gray treefrogsHyla versicolorandH. chrysoscelis

Irwin

Lee

2003

Journal of Experimental Biology

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SUMMARYThe physiological responses supporting freeze tolerance in anurans are well known, but the evolution of this trait remains little studied. This is the first common-garden study of geographic variation in cryoprotective responses to freezing and the degree of freeze tolerance. We studied the gray treefrogs(Hyla versicolor and H. chrysoscelis) from sympatric sites in Minnesota, Indiana and Missouri. Patterns in the literature suggest that northern frogs produce more cryoprotectants upon freezing, but we found no geographic variation in cryoprotective responses or degree of freeze tolerance. The concentration of glucose produced upon freezing was higher than previously reported for this species (liver: 475 μmol g–1dry mass). Unfrozen frogs had high levels of glycerol (liver: approx. 150μmol g–1 dry mass), and did not produce more upon freezing. Liver glycogen content (concentration multiplied by liver mass) was highest in frogs from Minnesota and Missouri, and was stored in preference to lipids in Minnesota frogs, possibly to provide energy for the longer northern winters. Minnesota frogs accumulated more ice (53.4±1.8%) after freezing to–2.5°C than Indiana frogs (45.5±3.3%). The two species differed in body size but not in any of the physiological parameters measured. We conclude that these populations show no adaptive variation in freeze tolerance and that comparing published studies may be misleading because of different acclimation and feeding regimes.

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“…Frogs accumulate large glycogen deposits in the autumn, which must arise from gluconeogenesis, given their carnivorous diets (Blier and Guderley 1986). Hepatic gluconeogenesis has been difficult to quantify, although Woof and Janssens (1978) and Blier and Guderley (1986) have reported activities of liver enzymes necessary for glucose production.…”

Section: Gluconeogenesis and Dietmentioning

confidence: 99%

Section: Gluconeogenesis and Dietmentioning

confidence: 99%

“…Hepatic gluconeogenesis has been difficult to quantify, although Woof and Janssens (1978) and Blier and Guderley (1986) have reported activities of liver enzymes necessary for glucose production. Fasting at either 22 or 4°C increased liver PEPCK, but decreased FBPase activities below those of PEPCK in Rana pipiens (Blier and Guderley 1986). Injection of cortisol led to confusing and often conflicting changes in enzyme activities, leading Woof and Janssens (1978) to conclude that low metabolic rates and seasonal effects may mask cortisol actions.…”

Section: Gluconeogenesis and Dietmentioning

confidence: 99%

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Adaptation, constraint, and the function of the gluconeogenic pathway

Moon¹

1988

Can. J. Zool.

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and the function of the gluconeogenic pathway. Can. J . Zool. 66: 1059 -1068.Gluconeogenesis is responsible for the de novo synthesis of glucose (and glycogen) from precursors including lactate, amino acids, glycerol, and fructose. This metabolic sequence is highly constrained by design features including enzyme composition and tissue localization, but demonstrates a variety of adaptive patterns which are critical to the maintenance of blood glucose levels optimal for animal function. This review identifies the adaptive responses of gluconeogenesis when glucose levels are challenged by changes in diet (both quality and quantity) and in activity level, and by environmental disturbances. Five adaptive patterns are identified: (i) quantitative changes in gluconeogenic enzyme activities and their subcellular distribution; (ii) alterations in tissue demand for glucose; (iii) existence of in situ skeletal muscle lactate cycling; (iv) quantity and type of gluconeogenic precursors; and (v) regulation of gluconeogenesis. The validity of the omnivorous mammalian model in our understanding of gluconeogenesis is discussed. MOON, T. W. 1988. Adaptation, constraint, and the function of the gluconeogenic pathway. Can. J. Zool. 66 : 1059 -1068.La glyconCogCnkse est responsable de la synthkse de novo du glucose (et du glycogkne) a partir de precurseurs, notamment le lactate, les acides aminCs, le glycCrol et le fructose. Cette sequence mCtabolique est soumise aux contraintes imposees par des caractCristiques structurales, telles la nature des enzymes et leur repartition dans les tissus, mais fait preuve de propriCtCs d'adaptation determinantes pour que soient maintenues dans le sang des concentrations glycCmiques essentielles au fonctionnement optimal de I'animal. Cette revision a pour but d'identifier les reactions d'adaptation de la glyconCogCnkse lorsque les concentrations glycCmiques sont menacees par des changements (qualitatifs et quantitatifs) dans le rkgime alimentaire et dans l'intensitk de I'activitC, et aussi par des perturbations de l'environnement. Cinq propriCtCs d'adaptation ont pu etre reconnues : (i) des changements quantitatifs dans I'activitC des enzymes de la glyconCogCnkse et dans leur repartition au niveau infracellulaire, (ii) des modifications de la demande tissulaire en glucose, (iii) I'existence d'un cycle du lactate in situ dans les muscles squelettiques, (iv) la quantitC et le type particuliers des precurseurs glyconCogCniques et (v) la regulation de la glyconeogenkse. La validit6 du modkle du mammifkre omnivore pour faciliter la comprehension de la glyconCogCnkse fait I'objet d'une discussion.[Traduit par la revue]

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The Enzymatic and Metabolic Effects of Extended Food Deprivation in Rana pipiens

Cited by 6 publications

References 29 publications

Enzymatic capacities of metabolic fuel use in cuttlefish (Sepia officinalis) and responses to food deprivation: insight into the metabolic organization and starvation survival strategy of cephalopods

Enzymatic capacities of metabolic fuel use in cuttlefish (Sepia officinalis) and responses to food deprivation: insight into the metabolic organization and starvation survival strategy of cephalopods

Geographic variation in energy storage and physiological responses to freezing in the gray treefrogsHyla versicolorandH. chrysoscelis

Adaptation, constraint, and the function of the gluconeogenic pathway

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