Rapid activation of glycogen phosphorylase by steroid hormones in cultured rat hepatocytes

Gómez-Muñoz, Antonio; Hales, Paul; Brindley, David N.; Sancho, María J.

doi:10.1042/bj2620417

Cited by 30 publications

(29 citation statements)

References 53 publications

(62 reference statements)

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“…While there is no evidence for any direct effects of cortisol on fish muscle glycogen metabolism, dexamethasone (a glucocorticoid analog) increases the activities of both Phos a and GSase I in rat hepatocyte primary culture, and stimulates glycogenolysis. These effects are independent of changes in the levels of Phos or GSase mRNA or protein synthesis, but dependent upon extracellular [Ca 2+ ], suggesting glucocorticoids may activate Phos and GSase by modifying their phosphorylation state (Baqué et al, 1986;Gomez-Muñoz et al, 1989). Current hypotheses are that glucocorticoids initiate rapid signaling via nongenomic mechanisms, though whether membrane-initiated steroid signaling is the proximate cause remains to be seen (for reviews, see Falkenstein et al, 2000;Lösel and Wehling, 2003).…”

Section: Discussionmentioning

confidence: 99%

A regulatory role for cortisol in muscle glycogen metabolism in rainbow troutOncorhynchus mykissWalbaum

Milligan

2003

Journal of Experimental Biology

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SUMMARY To test the hypothesis that cortisol has a regulatory role in fish muscle glycogenesis post-exercise, rainbow trout were treated 1 h prior to exercise with either saline (control) or metyrapone (2-methyl-1,2-di-3-pyridyl-1-propanone) to block cortisol synthesis. Following exercise(time 0), half of the metyrapone-treated fish received a single injection of cortisol, to mimic the post-exercise rise usually observed. Muscle glycogen and the relative activities of glycogen phosphorylase a (Phos a) and glycogen synthase I (GSase I), regulatory enzymes for glycogen resynthesis, were monitored 4 h post-exercise. Metyrapone treatment succeeded in blocking the post-exercise rise in plasma cortisol(17±2 vs 118±13 ng ml–1 in controls at time 0), and cortisol injection resulted in a larger and more prolonged cortisol increase than in controls (159±22 vs 121±14 ng ml–1 in controls at 1 h). Muscle glycogen was completely restored in the metyrapone-treated fish within 2 h after exercise(8.3±0.6 vs 8±0.7 μmol g–1pre-exercise), only partially restored in control fish at 4 h (5.4±01.4 vs 8.8±1.3 μmol g–1 pre-exercise), and not at all in cortisol-treated fish (1.0±0.5 μmol g–1at 4 h). The rapid glycogen resynthesis in the metyrapone-treated fish was associated with a more rapid inactivation of Phos a and stimulation of GSase I compared to controls. In cortisol-treated fish, Phos a activity persisted throughout 4 h post-exercise; there was also a significant stimulation of GSase I activity. As a consequence of dual activation of Phos a and GSase I, glycogen cycling probably occurred, thus preventing net synthesis. This explains why the post-exercise elevation of cortisol inhibits net glycogen synthesis in trout muscle.

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Section: Discussionmentioning

confidence: 99%

A regulatory role for cortisol in muscle glycogen metabolism in rainbow troutOncorhynchus mykissWalbaum

Milligan

2003

Journal of Experimental Biology

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“…Rates of lactate release were calculated from lactate accumulated in the incubation medium as measured with a spectrophotometric lactate dehydrogenase method [20]. Intracellular accumulation of 2-deoxy-d-[ 3 H 2,6 ]glucose was determined as described [19] and was corrected using d-[U- 14 C]sucrose as a marker for the extracellular space (referred to as glucose transport). The net rate of methionine incorporation into protein was calculated from the conversion of […”

Section: Analysesmentioning

confidence: 99%

“…Measurement period After pretreatment, muscles were transferred into identical medium (one muscle strip in 3 ml medium per flask) additionally supplemented with trace amounts of d-[U- 14 …”

Section: Muscle Incubationmentioning

confidence: 99%

“…Whereas effects of progesterone on pancreatic beta cells, hepatocytes and adipocytes [7,[13][14][15] are likely to influence glucose metabolism of skeletal muscle indirectly, the possible contribution of direct actions on muscle has received little attention. Based on promising results reported two decades ago [10,16], the present study set out to close this gap in knowledge.…”

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confidence: 99%

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Progesterone impairs cell respiration and suppresses a compensatory increase in glucose transport in isolated rat skeletal muscle: a non-genomic mechanism contributing to metabolic adaptation to late pregnancy?

et al. 2007

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Aims/hypothesis The aim of the study was to gain better insight into the mechanisms responsible for impaired glucose metabolism during late pregnancy. We explored the direct effects of progesterone on glucose metabolism of skeletal muscle. Methods Specimens of skeletal muscle from untreated rats were incubated with progesterone and rates of substrate fluxes through the various pathways of glucose metabolism were analysed. Results Progesterone dose-dependently reduced the rates of glucose and pyruvate oxidation (insulin-stimulated rates after 5 h of exposure to 1 and 10 μmol/l progesterone: glucose oxidation, −6±4%, NS, and −39±4%, p<0.001; pyruvate oxidation, −28±2% and −55±4%, p<0.001 each) and increased lactate release (+28±4% and +58±9%, p<0.005 each), which indicated inhibition of mitochondrial respiratory function. Impairment of cell respiration, e.g. by the specific inhibitor rotenone, is known to trigger a compensatory increase in glucose transport, but this response was blunted in the case of progesterone (change of glucose transport in response to 10 μmol/l progesterone vs 60 nmol/l rotenone, both causing a reduction in glucose oxidation by −39%: progesterone, +14±8% vs rotenone, +84±23%, p< 0.03). Further experiments dealt with the underlying mechanisms and revealed a rapid mode of action (50 μmol/l progesterone, reduction in insulin-stimulated glucose oxidation after 30 min: −29±7%, p<0.01) not affected by blockers of gene expression or the nuclear progesterone receptor. Conclusions/interpretation Progesterone inhibits cell respiration and at the same time suppresses a compensatory increase in glucose transport, causing cellular carbohydrate deficiency in isolated rat skeletal muscle. This effect is mediated by a direct, rapid and non-genomic mechanism and could contribute to pregnancy-associated changes in glucose homeostasis.

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“…Moreover, it has been described that cortisol and other steroid hormones modify calcium metabolism and alter the cyclic nucleotide levels, inducing the stimulation of calcium binding to liver plasma membrane [9][10][11]. It has been reported that testosterone, estradiol, progesterone, dexamethasone and cortisol provoke a rapid activation of glycogen phosphorylase in liver and cultured rat hepatocytes [12,13]. This glycogenolytic effect is earlier than and independent of the stimulation of protein synthesis and it is not accompanied by a rise in cAMP levels.…”

mentioning

confidence: 94%

Characterization of specific corticosterone binding sites in adrenal cortex plasma membrane and their localization by autoradiographic studies

Andrés

Marino

et al. 1997

Cellular and Molecular Life Sciences (CMLS)

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Specific corticosterone binding to calf adrenal cortex plasma membrane was measured using the biologically active radioligand [3H]corticosterone. Corticosterone binding was found to be time-dependent, saturable and reversible, and was reduced by more than 70% when membranes were pretreated with proteases. The population of corticosterone binding sites in calf adrenal cortex plasma membrane was homogeneous and displayed the following characteristics: equilibrium dissociation constant Kd = 77 +/- 8 nM and maximum specific binding capacity Bmax = 70,378 +/- 6,385 fmol/mg protein. The relative affinities of several structural analogues of steroids were deduced from competition assays. From these experiments we can conclude that the plasma membrane binding site characterized is selective for corticosterone and progesterone derivatives, and different from nuclear glucocorticoid, mineralocorticoid, estrogen and progestin receptors. Likewise, this corticosterone binding site is independent of mineralocorticoid and Na+, K(+)-ATPase digitalis receptors. From autoradiographic studies we suggest these corticosterone binding sites are located in the whole adrenal cortex.

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Rapid activation of glycogen phosphorylase by steroid hormones in cultured rat hepatocytes

Cited by 30 publications

References 53 publications

A regulatory role for cortisol in muscle glycogen metabolism in rainbow troutOncorhynchus mykissWalbaum

A regulatory role for cortisol in muscle glycogen metabolism in rainbow troutOncorhynchus mykissWalbaum

Progesterone impairs cell respiration and suppresses a compensatory increase in glucose transport in isolated rat skeletal muscle: a non-genomic mechanism contributing to metabolic adaptation to late pregnancy?

Characterization of specific corticosterone binding sites in adrenal cortex plasma membrane and their localization by autoradiographic studies

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