Decrease in liver norepinephrine in response to exercise and hypoglycemia

Winder, W. W.; Beattie, M. A.; Piquette, Craig A.; Holman, R. T.

doi:10.1152/ajpregu.1983.244.6.r845

Cited by 5 publications

(7 citation statements)

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“…The increase in hepatic norepinephrine spillover observed in the present study is consistent with the demonstration that the rat liver is depleted of norepinephrine during prolonged exercise due, presumably, to norepinephrine release from sympathetic nerve terminals in the liver (29). Sympathetic innervation of the liver has been proposed to have an important function in the stimulation of hepatic glucose production during exercise on the basis of two premises.…”

supporting

confidence: 90%

Sympathetic drive to liver and nonhepatic splanchnic tissue during heavy exercise

Coker

Krishna

Lacy

et al. 1997

Journal of Applied Physiology

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The contribution of sympathetic drive and vascular catecholamine delivery to the splanchnic bed during heavy exercise was studied in dogs that underwent a laparotomy during which flow probes were implanted onto the portal vein and hepatic artery and catheters were inserted into the carotid artery, portal vein, and hepatic vein. At least 16 days after surgery, dogs completed a 20-min heavy exercise protocol (mean work rate of 5.7 +/- 1 miles/h, 20 +/- 2% grade). Arterial epinephrine (Epi) and norepinephrine (NE) increased by approximately 500 and approximately 900 pg/ml, respectively, after 20 min of heavy exercise. Because Epi is not released from the splanchnic bed and because Epi fractional extraction (FX) = NE FX, NE uptake by splanchnic tissue can be calculated despite simultaneous release of NE. Basal nonhepatic splanchnic (NHS) FX increased from a basal rate of 0.52 +/- 0.09 to a peak of 0.64 +/- 0.05 at 10 min of exercise. Hepatic Epi FX increased from a basal rate of 0.68 +/- 0.10 to 0.81 +/- 0.09 at 20 min of exercise. Even though NHS extraction of Epi reduced portal vein Epi levels by approximately 60%, the release of NE from NHS tissue maintained portal vein NE at levels similar to those in arterial blood. NHS NE spillover increased from a basal rate of 5.7 +/- 1.4 to 11.7 +/- 2.8 ng x kg(-1) x min(-1) at 20 min of exercise. Hepatic NE spillover increased from a basal rate of 5.0 +/- 1.2 ng x kg(-1) x min(-1) to a peak of 14.2 +/- 2.8 ng x kg(-1) x min(-1) at 15 min of exercise. These results show that 1) approximately two- and threefold increases in NHS and hepatic NE spillover occur during heavy exercise, demonstrating that sympathetic drive to these tissues contributes to the increase in circulating NE; 2) the high catecholamine FX by the NHS tissues results in an Epi level at the liver that is considerably lower than that in the arterial blood; and 3) circulating NE delivery to the liver is sustained despite high catecholamine FX due to simultaneous NHS NE release.

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supporting

confidence: 90%

Sympathetic drive to liver and nonhepatic splanchnic tissue during heavy exercise

Coker

Krishna

Lacy

et al. 1997

Journal of Applied Physiology

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“…A few reports in the literature discuss the effects of physical training and acute exercise on changes in liver norepinephrine. 9,15 However, less is known about the influence of a hypoxic condition and HE training on norepinephrine in the liver. In our experiments, the liver norepinephrine concentrations in HS and HE groups were significantly lower when compared with concentrations for the NS group.…”

Section: Discussionmentioning

confidence: 99%

Effect of Hypoxia on Norepinephrine of Various Tissues in Rats

Ohkuwa

Itoh

Yamamoto

et al. 2005

Wilderness & Environmental Medicine

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“…Im in uitro-Test fallt die Aktivitat dieser Enzyme in Gegenwart von cAMP ab. Als Erklarung hierfiir wird eine allosterische Hemmung durch cAMP angesehen (GARGES et al 1982, SWILLENS et al 1982 (WINDER et al 1982, 1983, PILKIS et al 1986). Dabei wurden die zwei Isoenzyme der CAMP-abhangigen Proteinkinase unterschiedlichen regulatorischen StellgroDen zugeordnet (MUMBY et al 1988).…”

Section: Diskussionunclassified

Reinigung und Charakterisierung von cAMP‐abhängigen Proteinkinasen bei Hefen in einem Saccharomyces cerevisiae Wildstamm und ausgewählten Mutanten des cAMP‐Stoffwechsels

Sachse¹,

Jeleń²

1991

J. Basic Microbiol.

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Protein kinases represent a diverse family of enzymes that play a critical role in regulation. Among nearly 100 known protein kinases, the cAMP-dependent enzyme is best understood biochemically. Unlike other protein kinases, cAMP-dependent protein kinase consists of two different types of subunits that dissociate, a regulatory subunit (R), which is the receptor for cAMP, and a catalytic subunit (C). In the absence of cAMP, the enzyme exists as an inactive tetramer, R2C2. The binding of intracellular cAMP to the R subunit decreases the affinity of the R subunit for the C subunit by approximately four orders of magnitude and, under physiological conditions, leads to dissociation of the holoenzyme into R2(cAMP)4 dimer and two free C subunits that are catalytically active. Mutants of the cAMP metabolism, adenylate cyclase and cell cycle mutants, provided further information about protein synthesis and cellular growth in Saccharomyces cerevisiae. The purified protein kinases were divided into different types according to their elution profiles from the DEAE-cellulose matrix. Two types of cAMP-dependent and two types of cAMP-independent protein kinases were isolated from the wild strain. Differences in the activities of the kinases in the mutants showed a close relationship to the locus of the respective mutations in the cell-cycle. Some properties of the protein kinases are discussed with respect to individual mutations.

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Decrease in liver norepinephrine in response to exercise and hypoglycemia

Cited by 5 publications

References 0 publications

Sympathetic drive to liver and nonhepatic splanchnic tissue during heavy exercise

Sympathetic drive to liver and nonhepatic splanchnic tissue during heavy exercise

Effect of Hypoxia on Norepinephrine of Various Tissues in Rats

Reinigung und Charakterisierung von cAMP‐abhängigen Proteinkinasen bei Hefen in einem Saccharomyces cerevisiae Wildstamm und ausgewählten Mutanten des cAMP‐Stoffwechsels

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