Allometry of mammalian cellular oxygen consumption

Porter, Richard K.

doi:10.1007/pl00000902

Cited by 77 publications

(83 citation statements)

References 47 publications

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“…Doses of PC-SPES used in our studies were calculated using an allometric exponent of 0.75 (based on whole body oxygen consumption) (Porter, 2001) and agree with the previous work of Kubota et al (2000). PC-SPES doses of 50 and 250 mg/kg/day in a 200-mg rat translates to approximately three and 13 capsules of PC-SPES per day, respectively, for a 70-kg human.…”

Section: Downloaded Fromsupporting

confidence: 71%

In Vivo Effect of PC-SPES on Prostate Growth and Hepatic CYP3A Expression in Rats

Wadsworth¹,

Poonyagariyagorn²,

Sullivan³

et al. 2003

J Pharmacol Exp Ther

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PC-SPES, a proprietary mixture composed of eight different herbs, is used worldwide as an alternative treatment by prostate cancer patients. It has been suggested that the clinical and in vitro antitumor activity exhibited by PC-SPES may be due to estrogenic activity, which in turn may be mediated by the presence of undeclared prescription drug contaminants. Here, we evaluated the in vivo effects of two different commercial lots of PC-SPES in male and female rats. Our high-pressure liquid chromatography analysis coupled with gas chromatography/ mass spectrometry analysis by an independent laboratory suggested that PC-SPES lot 5430125 was contaminated with diethylstilbestrol (DES), whereas lot 5431249 was not. Treatment of male rats with PC-SPES lot 5430125 or DES alone reduced the weight of androgen target organs and decreased circulating levels of sex steroids and luteinizing hormone, whereas lot 5431249 was without effect. In addition, lot 5430125 and DES, but not lot 5431249 increased uterine weight in female rats. These results suggest that the inhibitory effects on androgen targets are mediated through suppression of the hypothalamicpituitary axis and this suppression is probably due to DES contamination. We assessed the effects of both lots of PC-SPES and DES on hepatic cytochrome P450 expression and activity. Both lots of PC-SPES and DES reduced CYP3A activity and protein levels. Because the response of CYP3A to PC-SPES was not dependent on whether it contained DES, a phytochemical component of PC-SPES is most likely responsible for this effect. Inhibition of CYP3A has important implications for potential herbal-drug interactions.

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Section: Downloaded Fromsupporting

confidence: 71%

In Vivo Effect of PC-SPES on Prostate Growth and Hepatic CYP3A Expression in Rats

Wadsworth¹,

Poonyagariyagorn²,

Sullivan³

et al. 2003

J Pharmacol Exp Ther

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“…MnSOD is localised exclusively within the mitochondrial matrix, so between-species differences in cellular mitochondrial abundance would influence scaling behaviour of any mitochondrial protein. Although the scaling of mitochondrial abundance with species MLSP should be negative (Porter 2001), and therefore further enforce the above correlation, we nonetheless measured CS activity as a proxy for mitochondrial number and found no relationship between brain CS activity and MLSP (data not shown). Also, MnSOD did not correlate with CS activity (data not shown), further indicating that the MnSOD correlation was not due simply to increased mitochondrial abundance in long-lived species.…”

Section: Resultsmentioning

confidence: 61%

“…Previous comparative studies of SOD have simply measured total activity, or KCN inhibitable activity, in tissue homogenates (Tolmasoff et al 1980;Sohal et al 1990;López-Torres et al 1993;Pérez-Campo et al 1994). As MnSOD is an exclusively mitochondrial enzyme and mitochondrial abundance scales negatively with species body mass in most tissues (Porter 2001), it is also necessary to take this into account when assessing relative MnSOD levels. Similar to CuZnSOD, we found no correlation between the activity of liver or heart MnSOD and animal MLSP.…”

Section: Discussionmentioning

confidence: 99%

Antioxidant enzyme activities are not broadly correlated with longevity in 14 vertebrate endotherm species

Page

Richardson

Wiens

et al. 2010

AGE

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The free radical theory of ageing posits that accrual of oxidative damage underlies the increased cellular, tissue and organ dysfunction and failure associated with advanced age. In support of this theory, cellular resistance to oxidative stress is highly correlated with life span, suggesting that prevention or repair of oxidative damage might indeed be essential for longevity. To test the hypothesis that the prevention of oxidative damage underlies longevity, we measured the activities of the five major intracellular antioxidant enzymes in brain, heart and liver tissue of 14 mammalian and avian species with maximum life spans (MLSPs) ranging from 3 years to over 100 years. Our data set included Snell dwarf mice in which life span is increased by ∼50% compared to their normal littermates. We found that CuZn superoxide dismutase, the major cytosolic superoxide dismutase, showed no correlation with MLSP in any of the three organs. Similarly, neither glutathione peroxidase nor glutathione reductase activities correlated with MLSP. MnSOD, the sole mitochondrial superoxide dismutase in mammals and birds, was positively correlated with MLSP only for brain tissue. This same trend was observed for catalase. For all correlational data, effects of body mass and phylogenetic relatedness were removed using residual analysis and Felsenstein's phylogenetically independent contrasts. Our results are not consistent with a causal role for intracellular antioxidant enzymes in longevity, similar to recent reports from studies utilising genetic modifications of mice (Pérez et al., Biochim Biophys Acta 1790:1005-1014). However, our results indicate a specific augmentation of reactive oxygen species neutralising activities in brain associated with longevity.

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“…A number of studies have compared the scaling of metabolic rate of individual cells of endotherms (Porter 2001;West et al 2002). Some of the best data available come from Porter and colleagues (Porter andBrand 1995a, 1995b;Porter 2001) and Brown et al (2007), although the results of these two studies are totally opposed.…”

Section: Implications For Capillary Densities Cellular Metabolic Ratmentioning

confidence: 99%

“…Some of the best data available come from Porter and colleagues (Porter andBrand 1995a, 1995b;Porter 2001) and Brown et al (2007), although the results of these two studies are totally opposed. Porter and Brand measured the metabolic rates of isolated liver cells taken from mammals ranging in size from 20-g mice to 200-kg horses and found that they do indeed scale with mass Ϫ0.18 (Porter and Brand 1995b), close to the WBE expectation of mass Ϫ0.25 for freshly isolated cells.…”

Section: Implications For Capillary Densities Cellular Metabolic Ratmentioning

confidence: 99%

Testing Metabolic Theories

Kearney

White

2012

The American Naturalist

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. abstract: Metabolism is the process by which individual organisms acquire energy and materials from their environment and use them for maintenance, differentiation, growth, and reproduction. There has been a recent push to build an individual-based metabolic underpinning into ecological theory-that is, a metabolic theory of ecology. However, the two main theories of individual metabolism that have been applied in ecology-Kooijman's dynamic energy budget (DEB) theory and the West, Brown, and Enquist (WBE) theoryhave fundamentally different assumptions. Surprisingly, the core assumptions of these two theories have not been rigorously compared from an empirical perspective. Before we can build an understanding of ecology on the basis of individual metabolism, we must resolve the differences between these theories and thus set the appropriate foundation. Here we compare the DEB and WBE theories in detail as applied to ontogenetic growth and metabolic scaling, from which we identify circumstances where their predictions diverge most strongly. Promising experimental areas include manipulative studies of tissue regeneration, body shape, body condition, temperature, and oxygen. Much empirical work designed specifically with DEB and WBE theory in mind is required before any consensus can be reached on the appropriate theoretical basis for a metabolic theory of ecology.

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Allometry of mammalian cellular oxygen consumption

Cited by 77 publications

References 47 publications

In Vivo Effect of PC-SPES on Prostate Growth and Hepatic CYP3A Expression in Rats

In Vivo Effect of PC-SPES on Prostate Growth and Hepatic CYP3A Expression in Rats

Antioxidant enzyme activities are not broadly correlated with longevity in 14 vertebrate endotherm species

Testing Metabolic Theories

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