| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
-tocopherol content of mitochondria on the production of superoxide anion radicals
Department of Biological Sciences, Southern Methodist University, Dallas, Texas 75275, USA
1Correspondence: Department of Biological Sciences, Southern Methodist University, 220 Fondren Science Bldg., Dallas, TX 75275, USA. E-mail: rsohal{at}mail.smu.edu
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
-tocopherol on the rate of mitochondrial superoxide anion radical
(
) generation were examined in
skeletal muscle, liver, and kidney of 24-month-old mice. Mice were
orally administered -tocopherol (200
mg·kg-1·day-1) alone, CoQ10
(123 mg·kg-1·day-1) alone, or the two
together for 13 wk. Administration of -tocopherol resulted in an
~sevenfold elevation of mitochondrial -tocopherol content. Intake
of CoQ10 alone caused an ~fivefold increase in CoQ
content (CoQ9 and/or CoQ10) and -tocopherol
of mitochondria. The rate of generation by submitochondrial particles (SMPs) was inversely related
to their -tocopherol content but unrelated to CoQ content.
Experimental in vitro augmentation of SMPs with varying
amounts of -tocopherol caused an up to ~50% decrease in the rate
of generation. Similar in
vitro augmentations of SMPs with CoQ10 had
previously been found to have no effect on the rate of
generation The
CoQ10-induced elevation of -tocopherol in the present
study was inferred to be due to a ‘sparing/regeneration’ by CoQ.
Results indicate the involvement of -tocopherol in the elimination
of mitochondrially generated .—Lass,
A., Sohal, R. S. Effect of coenzyme Q10 and
-tocopherol content of mitochondria on the production of superoxide
anion radicals.
Key Words: antioxidants • free radicals • oxidative stress • aging
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
2
3
4
5)
. The superoxide anion
radical (), the first
molecular species in the univalent pathway of oxygen reduction, is
mainly generated in the mitochondrial electron transport chain
primarily by the autoxidation of ubisemiquinone (2
, 6
7
8
9)
.
The rate of mitochondrial
generation has been
shown to vary in different tissues (10)
and species
(11)
, and to be inversely correlated with the maximum life
span of mammalian (12)
and insect species
(13)
.
The nature of the mechanisms underlying the variations in the rate of
mitochondrial
generation is presently unclear; however, its elucidation is of
considerable importance for understanding the physiological and
pathological processes associated with oxidative stress. In a previous
study (12)
, we examined the relationship between the rate
of generation and
coenzyme Q (CoQ) content (CoQ9 plus
CoQ10) in submitochondrial particles (SMPs) of
various mammalian species. Although there was no demonstrable
correlation between the rate of
generation and the
total amount of CoQ, the amount of CoQ9, the
predominant CoQ homologue in relatively short-lived mammals, was found
to be directly related to the rate of
generation. In
contrast, the amount of CoQ10, the predominant
CoQ homologue in relatively long-lived mammals, exhibited an inverse
correlation with the rate of
generation. The
in vitro augmentation of mitochondrial CoQ with varying
amounts of CoQ10 had no effect on the rate of
generation, whereas
CoQ9 augmentation caused a small rise in the rate
of generation.
Altogether, results of this study suggested that factors additional to
the CoQ9 concentration were involved in the
determination of the rate of mitochondrial
generation
(12)
.
The purpose of the present study was to further explore the mechanisms
involved in the modulation of the rate of mitochondrial
generation. The
possibility that -tocopherol content of mitochondria may be one of
the factors governing the rate of mitochondrial
generation was
examined. The rationale for this hypothesis is that -tocopherol can
directly react with
(8
, 14
15
16)
(Eq. 1)
, forming the tocopheroxyl radical,
which in turn can react with ubiquinol (CoQH2,
the reduced form of CoQ) to regenerate -tocopherol
(17
18
19)
(Eq. 2)
. Furthermore, we previously demonstrated
that recycling of -tocopherol in mitochondrial membranes is directly
dependent on the molar ratio of CoQ and -tocopherol
(20)
. Collectively, such studies suggested an
interrelationship between CoQ, -tocopherol, and
generation.
 |
 |
generation can be varied experimentally by dietary supplementation with
-tocopherol and/or CoQ10. Elevation in the
in vivo amounts of mitochondrial -tocopherol and/or CoQ
(CoQ9 and/or CoQ10) was
achieved by the oral administration of -tocopherol alone,
CoQ10 alone, or both together. Results indicate
that increased amounts of -tocopherol, but not CoQ, cause a decrease
in the rate of
generation. The existence of a direct relationship between
mitochondrial -tocopherol concentration and the rate of
generation was
experimentally demonstrated by the in vitro augmentation of
mitochondria with varying amounts of -tocopherol. |
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
-tocopherol, -tocopherol acetate,
ferricytochrome c (type VI), superoxide dismutase (SOD),
rotenone, and antimycin A were purchased from Sigma (St. Louis, Mo.).
Ethylenedinitrilo-tetraacetic acid disodium salt dihydrate (EDTA) was
purchased from Fisher Scientific. Ubiquinol-9 and ubiquinol-10 were
obtained by reduction of corresponding quinones with sodium borohydride
(Sigma), as described by Takada et al. (21)
.
Animals
A total of 49 male C57BL/6JNia mice, 24 months of age were
housed 2 per cage in 30.4 x 18 x 12.8 cm clear
polycarbonate cages that were modified into two separate housing units
with a stainless steel divider. Mice were fed ad libitum and
housed at an ambient temperature of 23 ± 1°C, with a 12 h,
light-dark cycle beginning at 0600 h.
Separate groups of the mice were assigned to orally receive daily
treatment (0.1 ml) of either -tocopherol acetate (200 mg/kg body
mass) alone, CoQ10 (123 mg/kg body mass) alone,
-tocopherol acetate and CoQ10 together, or the
vehicle (soybean oil) for 13 wk. Mice were killed by carbon dioxide
asphyxiation 24 h after the last treatment.
Isolation of mitochondria
Tissues were homogenized in 10 volumes (w/v) of the indicated
tissue-specific isolation buffer. Mitochondria were isolated from the
supernatant by differential centrifugation. Liver, kidney, and upper
hind limb skeletal muscle were prepared, respectively, according to
Sohal et al. (22)
, Lash and Sall (23)
, and
Trounce et al. (24)
. Bovine heart mitochondria were
prepared as described previously (12)
. Samples to
determine the amounts of CoQ and -tocopherol were stored at -80°C
for up to 1 month. Protein content was determined by the BCA protein
assay, according to the manufacturer’s instructions (Pierce, Rockford,
Ill.).
Extraction and quantification of coenzyme Q and -tocopherol
Extractions were performed as described by Takada et al.
(21)
. Briefly, 20–100 µl of the sample, 10 µl EDTA
(10%, w/v), and 750 µl of hexane:ethanol (5:2) were mixed together
for 30 s, using a vortex. The mixture was centrifuged for 3 min at
4000 x g and 400 µl of the hexane layer was
collected, dried under a stream of helium, and dissolved in 100 µl of
ethanol.
Quantification of CoQ and -tocopherol was performed by HPLC
according to Lass and Sohal (20)
. An aliquot of the
ethanol extract (5–20 µl) was chromatographed on a reverse phase
C18 HPLC column (25.0 cm x 0.46 cm, 5 µM,
Supelco Inc., Bellefonte, Pa.), using a mobile phase consisting of
0.7% NaClO4 in ethanol:methanol:70%
HClO4 (900:100:1, v/v/v) at a flow rate of 1.2
ml/min. The eluent was monitored with an electrochemical detector (ESA
Coulochem II, ESA Inc., Bedford, Mass.). The settings of the
electrochemical detector were guard cell (upstream of the injector),
+200 mV; conditioning cell (downstream of the column), -550 mV;
analytical cell, +150 mV. The concentrations of ubiquinone-9,
ubiquinone-10, ubiquinol-9, ubiquinol-10, and (±)--tocopherol were
obtained by comparison of the peak areas with those of standard
solutions of known concentrations. Concentrations of
CoQ9 and CoQ10 represent
the sum of the respective quinone and quinol forms.
Preparation of SMPs
To prepare submitochondrial particles (SMPs), the mitochondrial
pellets of various tissues were resuspended in 30 mM potassium
phosphate buffer, pH 7.0, and sonicated three times (each consisting of
a 30 s pulse) at 1 min intervals, at 4°C. The sonicated
mitochondria were centrifuged at 8250 x g for 10 min
to remove the unbroken organelles; the supernatant was recentrifuged at
80,000 x g for 45 min, and the resulting pellet was
washed and resuspended in 0.1 M phosphate buffer, pH 7.4, as described
previously (11)
.
In vitro augmentation of bovine heart SMPs
with -tocopherol
Bovine heart SMPs (~0.6 µg protein in 0.1 mM potassium
phosphate buffer, pH 7.4) were freeze-dried and -tocopherol,
dissolved in pentane, was added to the residue to give a final
concentrations of ~0, 2.5, 5, 10, and 20 nmol/mg SMP protein. SMPs
were then dried under a stream of helium and 200 µl of 0.1 mM
potassium phosphate buffer (pH 7.4, at 4°C) was added. The mixture
was sonicated for ~2 s with a Branson 2200 water bath sonicator
(Branson Ultrasonics Co., Danbury, Conn.).
Measurement of superoxide anion radical generation
()
The rate of
generation by SMPs was measured as SOD-inhibitable reduction of
acetylated ferricytochrome c (25)
, as described
previously (11)
. The reaction mixture contained 10 µM
acetylated ferricytochrome c, 6 µM rotenone, 1.2 µM
antimycin A, 100 units of SOD/ml (in the reference cuvette), and
10–100 µg SMP protein in 100 mM potassium phosphate buffer, pH 7.4.
The reaction was started by addition of 7.5 mM succinate and the
reduction of acetylated ferricytochrome c was followed at
550 nm (
=27,700
M-1cm-1).
Measurement of oxygen consumption
The rate of respiration of SMPs was measured polarographically
using a Clark-type electrode (YSI Inc., Yellow Springs Instruments Co.,
Yellow Springs, Ohio) at 37°C. The incubation mixture consisted of
buffer (154 mM KCl, 3 mM MgCl2, 10 mM
KPO4, 0.1 mM EGTA, pH 7.4), 30–100 µg of SMP
protein, and 7 mM succinate.
Statistical analysis
Data for the amounts of -tocopherol,
CoQ9, and CoQ10 and rates
of generation and
oxygen consumption were analyzed separately by one-way analysis of
variance (ANOVA) for skeletal muscle, liver, and kidney. Planned
individual comparisons of each treatment group with the control group
were made using a single degree of freedom F test based on the analysis
error term. The effect of -tocopherol on the rates of
generation and oxygen
consumption was also evaluated by one-way ANOVA.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
-tocopherol alone, CoQ10 alone, both
together, or soybean oil (=control) for 13 wk. The amounts of
CoQ9, CoQ10, and
-tocopherol were subsequently determined in mitochondria isolated
from the upper hind limb skeletal muscle, liver, and kidney.
Effect of -tocopherol administration on mitochondrial
-tocopherol and CoQ content
The concentration of -tocopherol in mitochondria from all three
tissues examined was elevated in the experimental animals that were
administered exogenous -tocopherol; however, the magnitude of the
elevation varied in different tissues (Table 1
). For instance, the increase in -tocopherol content was 70% in the
skeletal muscle, 650% in the liver, and only 40% in the kidney.
Intake of -tocopherol alone had no effect on the amounts of
mitochondrial CoQ9 or
CoQ10.
|
Effect of CoQ10 administration on mitochondrial CoQ and
-tocopherol content
CoQ in the mouse mitochondria consisted of two main homologues,
CoQ9 and CoQ10. In the
control mice, CoQ9 constituted ~90% and
CoQ10 ~10% of the total amount of
mitochondrial CoQ. In the mice administered CoQ10
alone, mitochondrial CoQ10 content increased
370% in the liver, 70% in the kidney, and only 20% (n.s.) in the
skeletal muscle (Table 1)
. In contrast, the mitochondrial
CoQ9 content in these mice increased
significantly only in the kidney.
Rather unexpectedly, CoQ10 administration alone
was found to also cause an elevation in the mitochondrial
-tocopherol content. The magnitude of this increase was virtually
the same as that induced by the administration of -tocopherol alone,
viz, 90% in skeletal muscle, 690% in liver, and 7% in kidney (Table 1)
.
Effect of coadministration of -tocopherol and CoQ10
on their mitochondrial content
When -tocopherol and CoQ10 were
administered together, -tocopherol content of mitochondria was
elevated roughly to the same level as when -tocopherol was
administered alone (Table 1)
. In contrast, the magnitude of the
increases in the amounts of CoQ9 or
CoQ10 in such mice was less than that of those
administered CoQ10 alone.
Altogether, results of the studies involving -tocopherol and
CoQ10 intake indicated that -tocopherol
content of mitochondria can be greatly augmented by the administration
of either -tocopherol or CoQ10 to the mice. In
contrast, mitochondrial CoQ content (CoQ9 and/or
CoQ10) could be increased only by the
administration of CoQ10.
Effect of -tocopherol and/or CoQ10
administration on the rates of
generation and oxygen consumption of SMPs
The rates of
generation in SMPs of skeletal muscle, liver, and kidney of mice
administered -tocopherol alone (which had elevated levels of
-tocopherol, but not of CoQ9 or
CoQ10), were 15 to 35% lower than in the
controls (see Figs. 1
,
2and
3), whereas the rates of oxygen consumption of these SMPs remained
unchanged compared to controls (Figs. 1
2
3
, inset).
|
|
|
The rates of
generation in the SMPs of mice administered CoQ10
were found to be decreased in the skeletal muscle and liver (which had
elevated -tocopherol content), but not in the kidney (which showed
increases only in the levels of CoQ10 and
CoQ9 but not of -tocopherol; see Figs. 1
2
3
and Table 1
). Compared to controls, the rates of oxygen consumption of
SMPs in the CoQ10-administered mice remained
unaffected in skeletal muscle and liver but decreased in the kidney
(Figs. 1
2
3
, inset). These data suggested that increased levels of
mitochondrial -tocopherol were associated with decreased rates of
generation but
unrelated to the rates of oxygen consumption.
The rates of
generation in SMPs of
the skeletal muscle, liver, and kidney of mice administered
-tocopherol and CoQ10 together were ~20%
lower than in the controls (Figs. 1
2
3)
. In contrast, the rates of
oxygen consumption were unaffected in SMPs from liver and kidney, but
increased by ~15% in the SMPs of skeletal muscle (Figs. 1
2
3
,
inset).
To better understand their interrelationships, the rates of
generation by SMPs in
all the four groups of animals were correlated with the amounts of
-tocopherol, CoQ9,
CoQ10, and
CoQ9+CoQ10. The rates of
generation were found
to be inversely correlated with the amounts of mitochondrial
-tocopherol, reaching statistical significance in the liver and
kidney (P<0.05), but not skeletal muscle (Fig. 4
). In contrast, neither CoQ9,
CoQ10, nor the sum of the two were correlated
with the rates of
generation (data not shown).
|
Effect of in vitro -tocopherol augmentation of bovine heart SMPs
on the rates of generation and
oxygen consumption
To determine directly whether elevation in the amounts of
-tocopherol could specifically cause a decrease in the rate of
generation, bovine
heart SMPs were reconstituted with different amounts of -tocopherol.
Bovine heart SMPs were selected for this study for two main reasons.
First, the -tocopherol content of the bovine heart mitochondria is
more than 10-fold lower than that in the murine mitochondria. Thus, it
was thought that experimental variations in -tocopherol content
might elicit a relatively more explicit response in the bovine SMPs.
Second, a practical reason was that the relatively high amount of SMPs
needed for the reconstitution experiments could not be conveniently
obtained from the mouse.
The natural (endogenous) amounts of -tocopherol and
CoQ10 in bovine heart SMPs were, respectively,
0.02 ± 0.01 and 6.3 ± 0.12 nmol/mg protein. As shown in
Fig. 5
, elevation of the amounts of -tocopherol ranging from ~0
(controls) to 5 nmol/mg protein caused an up to ~50% decrease in the
rate of generation.
Relatively higher amounts of -tocopherol had no further effect on
the rate of
generation. In contrast, the rates of oxygen consumption in bovine
heart SMPs, augmented with different amounts of -tocopherol (0 to 20
nmol/mg protein), remained unaltered. Altogether, these results
indicated that elevation of -tocopherol content of mitochondria
in vitro or in vivo caused a decrease (maximally
50% and 30%, respectively) in the rate of
generation in SMPs.
|
We have previously shown (12)
that in vitro
augmentation of bovine heart SMPs with CoQ9
caused an elevation in the rates of
generation, whereas
CoQ10 augmentation had no effect. Rates of oxygen
consumption of such SMPs were unaffected by augmentation with
CoQ9 or CoQ10.
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
-tocopherol content in the mouse can cause a decrease
in the rate of
generation by SMPs without lowering their rate of oxygen consumption.
Elevation in mitochondrial -tocopherol concentration in mice can be
achieved by the administration of -tocopherol alone, of
CoQ10 alone, or of the two together.
A considerable degree of variation in the incorporation of
-tocopherol in the mitochondria was encountered in different
tissues. For instance, -tocopherol administration resulted in a
~1.5-fold increase in mitochondrial -tocopherol content in the
kidney and a ~7-fold elevation in the liver. Nevertheless,
mitochondrial -tocopherol content was found to be inversely
correlated in each tissue with the rate of
generation by SMPs.
Whether such a correlation was merely due to fortuitousness or
reflected a cause and effect relationship between -tocopherol and
generation was
resolved experimentally by the reconstitution of SMPs with varying
amounts of -tocopherol. The finding that -tocopherol augmentation
of SMPs could induce an up to 50% decrease in the rate of
generation
demonstrated the causal basis of this association as well as the
maximal limit of this effect. The observation that despite the
tremendous variations in the augmented amounts of -tocopherol (1.5
to 7-fold) in mitochondria in different tissues, the relative decrease
in the rate of
generation by SMPs remained rather constant (between 25 and 30%), also
supports the inference that the inhibitory effect of -tocopherol on
the rate of
generation may have a maximal limit. On the basis of such in
vitro as well as ex vivo data, it can be reasonably
concluded that -tocopherol is one of the factors governing the rate
of generation. We
previously found that augmentation of SMPs with
CoQ10 in vitro without altering the
-tocopherol content had no effect on the rate of
generation, whereas
augmentation with CoQ9, which is believed to be
relatively more oxidizable, resulted in an increase in the rate of
generation, which
would seem to rule out the possibility that the decline observed in the
rate of generation in
mice administered with CoQ10 was due to an
increase in the CoQ content.
The mechanism by which -tocopherol lowers the rate of
generation in SMPs is
presently unclear; however, there are several lines of evidence in the
literature suggesting that -tocopherol may interact with
. For instance, it has
been demonstrated that -tocopherol can react directly with
in the liposomal
membranes to form -tocopheroxyl radical (Eq. 1)
with a rate constant
of 4.5 x 103
M-1s-1 (8
, 14
15
16)
. More recently, Cadenas et al. (26)
have
shown that the chromanoxyl radical of Trolox, a water-soluble analog of
-tocopherol, can be reduced by
with a rate constant
of 4.5 x 108
M-1s-1 (Eq. 3)
. Since
this reaction is thermodynamically more favorable than the reaction
between and
-tocopherol (Eq. 1)
, the authors proposed that
might play a role in
the repair of -tocopheroxyl radical.
 |
and -tocopherol
cannot be determined on the basis of the present study, the results
clearly indicate that -tocopherol can lower the apparent rate of
generation. Since
-tocopherol decreases the rate of
generation by SMPs
without affecting the rate of their oxygen consumption, a physiological
implication of this study may be that -tocopherol decreases the
proportion of mitochondrially consumed oxygen that is diverted to the
production of .
Another perspective may be that whereas superoxide dismutase
constitutes the main mechanism for the elimination of
, -tocopherol acts
as an auxiliary in this process.
A notable effect of CoQ10 administration to the
mice was that it resulted in an increase not only in the CoQ content of
mitochondria, but also the mitochondrial level of -tocopherol, which
in turn was inversely correlated with a decrease in the rate of
generation. Indeed,
the magnitude of the increase in mitochondrial -tocopherol content
in mice administered CoQ10 alone was similar to
that achieved by administration of -tocopherol alone. In contrast,
-tocopherol administration to the mice increased only the level of
-tocopherol in mitochondria and not of CoQ, demonstrating that
CoQ10 is capable of enhancing the mitochondrial
-tocopherol level, but not vice versa. Several lines of
evidence suggest that this peculiar relationship may be due to a
‘sparing/regeneration’ effect of CoQ on -tocopherol. For instance,
CoQ has been shown in homogeneous solutions (19)
and
membranes (17
18
19
20)
to react with tocopheroxyl radicals, to
regenerate -tocopherol (Eq. 2)
. We have previously demonstrated that
the loss of -tocopherol in mitochondrial membranes can be
progressively stemmed by an elevation of the molar ratios of CoQ and
-tocopherol present (20)
. Although CoQ (particularly
the reduced, quinol form) is known to be able to scavenge radicals
(27
, 28)
, its reactivity with peroxyl radicals is much
lower than that of -tocopherol [ubiquinol-9:
k1 = 3.4 x
105 M-1
s-1 (29)
; -tocopherol:
k1 = 3.3 x
106 M-1
s-1 (30)
], which renders this a
less likely mechanism by which CoQ may spare -tocopherol. Another
explanation, albeit speculative, for the increase in mitochondrial
-tocopherol levels in CoQ10-administered
animals may be that the mitochondrial uptake of CoQ and of
-tocopherol are linked together so that an increase in the CoQ
content would necessarily elevate the -tocopherol concentration.
Although the actual mechanism remains obscure, any of these
aforementioned scenarios could result in a concomitant increase in
-tocopherol content after CoQ administration.
Altogether, results of this study indicate that enhancement of
mitochondrial -tocopherol content, either directly by the
administration of -tocopherol to the animals or indirectly by the
intake of CoQ10, can cause a decrease in
mitochondrial
generation. The in vitro studies, demonstrating the
inhibitory effects of -tocopherol on the rates of
generation of SMPs,
provide experimental confirmation of the existence of a cause and
effect relationship.
|
ACKNOWLEDGMENTS |
|---|
|
FOOTNOTES |
|---|
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
-tocopherol inhibits autooxidation of mitochondrial membranes. Arch. Biochem. Biophys. 352,229-236[Medline]
This article has been cited by other articles:
|
|
 |
|
  A. Storch, W. H. Jost, P. Vieregge, J. Spiegel, W. Greulich, J. Durner, T. Muller, A. Kupsch, H. Henningsen, W. H. Oertel, et al. Randomized, Double-blind, Placebo-Controlled Trial on Symptomatic Effects of Coenzyme Q10 in Parkinson Disease Arch Neurol, July 1, 2007; 64(7): 938 - 944. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S.-K. Park and T. A. Prolla Gene expression profiling studies of aging in cardiac and skeletal muscles Cardiovasc Res, May 1, 2005; 66(2): 205 - 212. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. A. Starkov, G. Fiskum, C. Chinopoulos, B. J. Lorenzo, S. E. Browne, M. S. Patel, and M. F. Beal Mitochondrial {alpha}-Ketoglutarate Dehydrogenase Complex Generates Reactive Oxygen Species J. Neurosci., September 8, 2004; 24(36): 7779 - 7788. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-A. Gomez, X. Molero, E. Vaquero, A. Alonso, A. Salas, and J.-R. Malagelada Vitamin E attenuates biochemical and morphological features associated with development of chronic pancreatitis Am J Physiol Gastrointest Liver Physiol, July 1, 2004; 287(1): G162 - G169. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. W. Shults, R. Haas, D. Oakes, K. Kieburtz, S. Plumb, I. Shoulson, R. Kurlan, M. F. Beal, J. Juncos, R. Watts, et al. The Effect of Coenzyme Q10 Therapy in Parkinson Disease Could Be Symptomatic--Reply Arch Neurol, August 1, 2003; 60(8): 1172 - 1173. [Full Text] [PDF]
|
|
|
|
 |
|
 F. Petrat, S. Pindiur, M. Kirsch, and H. de Groot NAD(P)H, a Primary Target of 1O2 in Mitochondria of Intact Cells J. Biol. Chem., January 24, 2003; 278(5): 3298 - 3307. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Jonassen, P. L. Larsen, and C. F. Clarke A dietary source of coenzyme Q is essential for growth of long-lived Caenorhabditis elegans clk-1 mutants PNAS, December 28, 2000; (2000) 21337498. [Abstract] [Full Text]
|
|
|
|
|
|
T. Jonassen, P. L. Larsen, and C. F. Clarke A dietary source of coenzyme Q is essential for growth of long-lived Caenorhabditis elegans clk-1 mutants PNAS, January 16, 2001; 98(2): 421 - 426. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
