Regulation of pyruvate dehydrogenase and pyruvate dehydrogenase phosphate phosphatase activity in rat epididymal fat-pads. Effects of starvation, alloxan-diabetes and high-fat diet

Stansbie, D.; Denton, R M; Bridges, B J; Pask, H. T.; Randle, P. J.

doi:10.1042/bj1540225

Cited by 106 publications

(56 citation statements)

References 35 publications

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“…These values are similar to those obtained by Stansbie et al [7] (49%) but differ from those obtained by ourselves and others using gastrocnemius or mixed hindlimb musclese.g. Hennig et al [4] (15%), Hagg et al [10] (22%0), and Caterson et al [8] (68%).…”

Section: Resultssupporting

confidence: 88%

“…This is due to difficulties with extraction and assay of the enzyme from this highly fibrous tissue. Indeed, reports of changes in °70PDHa have been variable both with regard to estimates of total PDH complex activity and %PDHa (compare [4,[7][8][9]). Despite this it has been reported that °70PDHa is reduced by starvation in gastrocnemius muscle [4,10] and that muscle PDH complex activity is increased by insulin [11].…”

Section: Introductionmentioning

confidence: 99%

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Effect of starvation and insulin in vivo on the activity of the pyruvate dehydrogenase complex in rat skeletal muscles

et al. 1989

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The in vivo responses of pyruvate dehydrogenase (PDH) complex to starvation and insulin was assessed in heart, diaphragm and red quadrieeps muscle. PDH complex activity was decreased by starvation (3.4-10.2-fold), the magnitude of change depending on muscle type. Insulin increased PDH activity in all muscle types. In fed rats, this effect was relatively small (1.25-1.29-fold). In starved rats there were effects in heart (4.3-fold) and red quadrioeps (l.7-fold) but no effect in diaphragm. These results demonstrate that PDH complex in different groups of muscle has different insulin sensitivity (particularly in tissues from starved animals).

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Section: Resultssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Effect of starvation and insulin in vivo on the activity of the pyruvate dehydrogenase complex in rat skeletal muscles

et al. 1989

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“…min-' . g tissue-' were found which, allowing for differences in assay temperature, are very similar to those reported for rat liver [6,9,10]; in addition 16-17% of the activity was in the active state, again in good agreement with [9,10].…”

Section: Resultssupporting

confidence: 82%

“…Samples of liver, perirenal adipose tissde or placenta were removed as quickly as possible and frozen in liquid nitrogen. Preparation of tissue extracts and assay of 'initial' (PDHa) and 'total' PDH activity were carried out as described by Stansbie et al [6] except that the assays were performed at 37'C instead of 192 30°C. Protein concentration of the homogenates was determined by the method in [7].…”

Section: Materials Aud Methodsmentioning

confidence: 99%

Pyruvate dehydrogenase and the regulation of glucose metabolism in ruminant tissues

1980

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“…49 Total PDHC activities in white adipose tissue were not measured in the present study. However, a previous study 13 reported that both active and total PDHC activities were depressed by high-fat feeding in epididymal fat pads of young male rats. Another study demonstrated that antecedent high-fat feeding prolonged the response of white adipose tissue PDHC to an intravenous glucose challenge in overnight-starved rats.…”

Section: Discussionmentioning

confidence: 82%

The impact of increased dietary lipid on the regulation of glucose uptake and oxidation by insulin in brown- and a range of white-adipose-tissue depots in vivo

Holness

Sugden

1999

Int J Obes

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OBJECTIVE: To determine: (a) whether active pyruvate dehydrogenase (PDH a ) activity in interscapular brown adipose tissue (IBAT) is acutely regulated by altered insulin status at euglycaemia; (b) the relationship between glucose uptakeaphosphorylation and PDH a activities in IBAT in vivo; and (c) the impact of increased dietary lipid on the regulation of glucose uptake and oxidation by insulin in IBAT in comparison with that exerted on various white adipose tissue depots. DESIGN: Rats were provided with either a standard diet (8% fat, 72% carbohydrate, by energy) or a diet moderately high in saturated fat (47%, by energy) and low in carbohydrate (33%, by energy) for four weeks. Rats were studied in the absorptive state, in the post-absorptive state or after 2.5 h euglycaemic hyperinsulinaemia. Tissues sampled included IBAT and four white adipose tissue depots, two abdominal (parametrial (PM) and perirenal (PR)) and two super®cial (subcutaneous (SC) and interscapular (IS)). MEASUREMENTS: Whole-body glucose disposal was estimated using [3-3 H]glucose. Glucose uptakeaphosphorylation in vivo was estimated using 2-deoxy[1-3 H]-D-glucose. Insulin action was evaluated using the euglycaemic-hyperinsulinaemic clamp technique. PDH a activity was assayed spectrophotometrically in freeze-clamped tissue extracts. PDH kinase (PDK) activities were assayed in mitochondrial extracts by rates of ATP-dependent PDH a inactivation. RESULTS: Whole-body glucose disposal was decreased by high-fat-feeding in the post-absorptive state (P`0.05) and during euglycaemic hyperinsulinaemia (P`0.01). Glucose transportaphosphorylation in IBAT was decreased by highfat feeding in the absorptive (P`0.001) and post-absorptive states (by 84%, P`0.05) and during steady-state euglycaemic hyperinsulinaemia (by 73%, P`0.001). IBAT PDH a activities were suppressed by high-fat feeding. Euglycaemic hyperinsulinaemia in post-absorptive control rats increased PDH a activities in IBAT (P`0.001) to values comparable to those found in the absorptive state. Although IBAT PDH a activities were increased by euglycaemic hyperinsulinaemia in post-absorptive high-fat-fed rats, they remained lower (by 55%; P`0.01) than those of controls. The failure of hyperinsulinaemia to normalise IBAT pyruvate dehydrogenase complex (PDHC) activities in high-fat-fed rats was associated with a stable 1.4-fold increase in IBAT PDK activity. High-fat feeding decreased glucose utilisation rates in the post-absorptive state in IS, but not in SC, PM or PR white adipose tissue depots. Euglycaemic hyperinsulinaemia signi®cantly increased glucose utilisation in three out of the four depots of the control rats, but did not elicit statistically-signi®cant changes in high-fat-fed rats. High-fat feeding in¯uenced PDH a activity in PR, but was without signi®cant effect on PDH a activity in PM, SC and IS. CONCLUSIONS: The results demonstrate that PDH a activity in the IBAT of rats maintained on standard diet responds to changes in insulin concentrations over the low physiological range, and that i...

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Regulation of pyruvate dehydrogenase and pyruvate dehydrogenase phosphate phosphatase activity in rat epididymal fat-pads. Effects of starvation, alloxan-diabetes and high-fat diet

Cited by 106 publications

References 35 publications

Effect of starvation and insulin in vivo on the activity of the pyruvate dehydrogenase complex in rat skeletal muscles

Effect of starvation and insulin in vivo on the activity of the pyruvate dehydrogenase complex in rat skeletal muscles

Pyruvate dehydrogenase and the regulation of glucose metabolism in ruminant tissues

The impact of increased dietary lipid on the regulation of glucose uptake and oxidation by insulin in brown- and a range of white-adipose-tissue depots in vivo

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