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1.
Summary. Muscle carnosine synthesis is limited by the availability of β-alanine. Thirteen male subjects were supplemented with β-alanine
(CarnoSyn™) for 4 wks, 8 of these for 10 wks. A biopsy of the vastus lateralis was obtained from 6 of the 8 at 0, 4 and 10 wks. Subjects undertook a cycle capacity test to determine total work done (TWD)
at 110% (CCT110%) of their maximum power (Wmax). Twelve matched subjects received a placebo. Eleven of these completed the CCT110% at 0 and 4 wks, and 8, 10 wks. Muscle biopsies were obtained from 5 of the 8 and one additional subject. Muscle carnosine
was significantly increased by +58.8% and +80.1% after 4 and 10 wks β-alanine supplementation. Carnosine, initially 1.71 times
higher in type IIa fibres, increased equally in both type I and IIa fibres. No increase was seen in control subjects. Taurine
was unchanged by 10 wks of supplementation. 4 wks β-alanine supplementation resulted in a significant increase in TWD (+13.0%);
with a further +3.2% increase at 10 wks. TWD was unchanged at 4 and 10 wks in the control subjects. The increase in TWD with
supplementation followed the increase in muscle carnosine. 相似文献
2.
Summary. Mice were supplemented with β-alanine (3%) in drinking water for one week. β-Alanine intake reduced hepatic taurine levels,
but elevated cysteine levels significantly. Hepatotoxicity of CCl4 in mice fed with β-alanine was decreased as determined by changes in serum enzyme activities. Hepatic glutathione and taurine
concentrations after CCl4 challenge were increased markedly by β-alanine intake. The enhanced availability of cysteine for synthesis of glutathione
and/or taurine appears to account for the hepatoprotective effects of β-alanine against CCl4-induced liver injury. 相似文献
3.
High-intensity exercise results in reduced substrate levels and accumulation of metabolites in the skeletal muscle. The accumulation
of these metabolites (e.g. ADP, Pi and H+) can have deleterious effects on skeletal muscle function and force generation, thus contributing to fatigue. Clearly this
is a challenge to sport and exercise performance and, as such, any intervention capable of reducing the negative impact of
these metabolites would be of use. Carnosine (β-alanyl-l-histidine) is a cytoplasmic dipeptide found in high concentrations in the skeletal muscle of both vertebrates and non-vertebrates
and is formed by bonding histidine and β-alanine in a reaction catalysed by carnosine synthase. Due to the pKa of its imidazole
ring (6.83) and its location within skeletal muscle, carnosine has a key role to play in intracellular pH buffering over the
physiological pH range, although other physiological roles for carnosine have also been suggested. The concentration of histidine
in muscle and plasma is high relative to its K
m with muscle carnosine synthase, whereas β-alanine exists in low concentration in muscle and has a higher K
m with muscle carnosine synthase, which indicates that it is the availability of β-alanine that is limiting to the synthesis
of carnosine in skeletal muscle. Thus, the elevation of muscle carnosine concentrations through the dietary intake of carnosine,
or chemically related dipeptides that release β-alanine on absorption, or supplementation with β-alanine directly could provide
a method of increasing intracellular buffering capacity during exercise, which could provide a means of increasing high-intensity
exercise capacity and performance. This paper reviews the available evidence relating to the effects of β-alanine supplementation
on muscle carnosine synthesis and the subsequent effects on exercise performance. In addition, the effects of training, with
or without β-alanine supplementation, on muscle carnosine concentrations are also reviewed. 相似文献
4.
Effects of high salt diets and taurine on the development of hypertension in the stroke-prone spontaneously hypertensive rat 总被引:3,自引:0,他引:3
Summary. Taurine is present in high concentrations in mammalian tissues and has been implicated in cardiovascular control mechanisms.
The aim of the present study was to evaluate the ability of taurine to attenuate salt-induced elevations in blood pressure
and markers of damage to the kidney and cardiovascular system in stroke prone spontaneously hypertensive rats (SPSHR). Male
SPSHR (6 weeks old) were placed on high salt diets that contained 1% (w/w) NaCl added to their normal chow for 84 days and
then were switched to 3% added NaCl for the remaining 63 days of the study. SPSHR was given 1.5% taurine in the drinking water
(n = 8), a taurine free diet (n = 8) or normal chow (n = 8). A final control group (n = 6) was not given high salt diets.
High salt diets caused an acceleration in the development of hypertension in all groups. Taurine supplementation reduced ventricular
hypertrophy and decreased urinary excretion of protein and creatinine. The taurine free diet did not alter serum or urinary
excretion of taurine, but did result in elevated urinary nitrogen excretion, increased serum cholesterol levels, and impaired
performance in a spatial learning task. Alterations in dietary taurine intake did not alter urinary or serum electrolytes
(Na+, K+), but taurine supplementation did attenuate a rise in serum calcium seen with the high salt diets. Urinary excretion (μg/24
h) of epinephrine and dopamine was significantly reduced in SPSHR given 1% NaCl in the diet, but this effect was not seen
in SPSHR on taurine free or supplemented diets. Taurine supplementation showed cardioprotective and renoprotective effects
in SPSHR given high salt diets.
Received April 12, 1999/Accepted September 13, 1999 相似文献
5.
Stout JR Cramer JT Zoeller RF Torok D Costa P Hoffman JR Harris RC O'Kroy J 《Amino acids》2007,32(3):381-386
Summary. This study examined the effects of 28 days of β-alanine supplementation on the physical working capacity at fatigue threshold
(PWCFT), ventilatory threshold (VT), maximal oxygen consumption (
O2-MAX), and time-to-exhaustion (TTE) in women. Twenty-two women (age ± SD 27.4 ± 6.1 yrs) participated and were randomly assigned
to either the β-alanine (CarnoSyn™) or Placebo (PL) group. Before (pre) and after (post) the supplementation period, participants
performed a continuous, incremental cycle ergometry test to exhaustion to determine the PWCFT, VT,
O2-MAX, and TTE. There was a 13.9, 12.6 and 2.5% increase (p < 0.05) in VT, PWCFT, and TTE, respectively, for the β-alanine group, with no changes in the PL (p > 0.05). There were no changes for
O2-MAX (p > 0.05) in either group. Results of this study indicate that β-alanine supplementation delays the onset of neuromuscular
fatigue (PWCFT) and the ventilatory threshold (VT) at submaximal workloads, and increase in TTE during maximal cycle ergometry performance.
However, β-alanine supplementation did not affect maximal aerobic power (
O2-MAX). In conclusion, β-alanine supplementation appears to improve submaximal cycle ergometry performance and TTE in young women,
perhaps as a result of an increased buffering capacity due to elevated muscle carnosine concentrations. 相似文献
6.
Parildar-Karpuzoğlu H Doğru-Abbasoğlu S Balkan J Aykaç-Toker G Uysal M 《Amino acids》2007,32(1):115-119
Summary. We aimed to investigate the effect of decreased taurine levels on endogenous and induced lipid peroxide levels in liver, brain,
heart and erythrocytes as well as prooxidant and antioxidant balance in the liver of rats administered β-alanine (3%, w/v)
in drinking water for 1 month to decrease taurine levels of tissues. This treatment caused significant decreases in taurine
levels of liver (86%), brain (36%) and heart (15%). We found that endogenous and ascorbic acid-, NADPH- and cumene hydroperoxide-induced
malondialdehyde (MDA) levels did not change in the liver, brain and heart homogenates following β-alanine treatment. Also,
H2O2-induced MDA levels remained unchanged in erythrocytes. In addition, we did not observe any changes in levels of MDA, diene
conjugates, glutathione, α-tocopherol, ascorbic acid and the activities of superoxide dismutase, glutathione peroxidase and
glutathione transferase in the liver. According to this, buffering or sequestering capacity of tissues to exogenous stimuli
was not influenced by reduced taurine levels in tissues of rats. 相似文献
7.
Silva LA Silveira PC Ronsani MM Souza PS Scheffer D Vieira LC Benetti M De Souza CT Pinho RA 《Cell biochemistry and function》2011,29(1):43-49
Infrequent exercise, typically involving eccentric actions, has been shown to cause oxidative stress and to damage muscle tissue. High taurine levels are present in skeletal muscle and may play a role in cellular defences against free radical‐mediated damage. This study investigates the effects of taurine supplementation on oxidative stress biomarkers after eccentric exercise (EE). Twenty‐four male rats were divided into the following groups (n = 6): control; EE; EE plus taurine (EE + Taurine); EE plus saline (EE + Saline). Taurine was administered as a 1‐ml 300 mg kg?1 per body weight (BW) day?1 solution in water by gavage, for 15 consecutive days. Starting on the 14th day of supplementation, the animals were submitted to one 90‐min downhill run session and constant velocity of 1·0 km h?1. Forty‐eight hours after the exercise session, the animals were killed and the quadriceps muscles were surgically removed. Production of superoxide anion, creatine kinase (CK) levels, lipoperoxidation, carbonylation, total thiol content and antioxidant enzyme were analysed. Taurine supplementation was found to decrease superoxide radical production, CK, lipoperoxidation and carbonylation levels and increased total thiol content in skeletal muscle, but it did not affect antioxidant enzyme activity after EE. The present study suggests that taurine affects skeletal muscle contraction by decreasing oxidative stress, in association with decreased superoxide radical production. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
8.
Summary. The objective of this study was to assess the effect of taurine-depletion on cardiovascular responses of rat to vasoactive
agents. Male Wistar-Kyoto (WKY) rats were given either tap water (control) or 3% β-alanine (taurine-depleted) for three weeks.
Thereafter, mean arterial pressure (MAP) and heart rate of the freely moving animal were measured in response to vasoactive
agents. Administration of phenylephine (5–40 μg/kg/min; i.v.) resulted in a similar and significant increase in MAP but a
reduction in heart rate in both control and taurine-depleted groups. On the other hand, administration of sodium nitroprusside
(15–300 μg/kg/min; i.v.) elicited a similar and significant reduction in MAP but increased heart rate in both groups. Lack
of a differential response to phenylephrine and sodium nitroprusside between the two groups suggests that baroreflex regulation
of cardiovascular function is not adversely affected by taurine-depletion. Administration of angiotensin II (0.1–3.0 μg/kg/min;
i.v.) resulted in a dose-related increase in the pressor response and a decrease in heart rate in both groups. However, angiotensin
II-induced pressor response was reduced in the taurine-depleted compared to the control rats (p < 0.05); heart rate was similarly
reduced in both groups. Acute exposure to β-alanine (3 g/kg; i.v., 30-minutes) did not alter angiotensin II-induced hemodynamic
responses. Similarly, incubation of aortic rings with β-alanine (40 mM, 30 minutes) did not affect the contractile responses
to angiotensin II. The results suggest that β-alanine, per se, does not affect angiotensin II-induced responses in rat. However, β-alanine-induced taurine depletion is associated with
a reduction in the pressor response to angiotensin II without impairing baroreflex function.
Received December 17, 1999/Accepted January 12, 2000 相似文献
9.
Role of taurine supplementation to prevent exercise-induced oxidative stress in healthy young men 总被引:2,自引:0,他引:2
Summary. To evaluate the protective effects of taurine supplementation on exercise-induced oxidative stress and exercise performance, eleven men aged 18–20 years were selected to participate in two identical bicycle ergometer exercises until exhaustion. Single cell gel assay (SCG assay) was used to study DNA damage in white blood cells (WBC). Pre-supplementation of taurine, a significant negative correlation was found between plasma taurine concentration before exercise and plasma thiobaribituric-acid reactive substance (TBARS) 6hr after exercise (r=–0.642, p<0.05). WBC showed a significant increase in DNA strand breakage 6hr and 24hr after exercise. Seven-day taurine supplementation reduced serum TBARS before exercise (p<0.05) and resulted in a significantly reduced DNA migration 24hr after exercise (p<0.01). Significant increases were also found in VO2max, exercise time to exhaustion and maximal workload in test with taurine supplementation (p<0.05). After supplementation, the change in taurine concentration showed positive correlations with the changes in exercise time to exhaustion and maximal workload. The results suggest that taurine may attenuate exercise-induced DNA damage and enhance the capacity of exercise due to its cellular protective properties. 相似文献
10.
Mühling J Nickolaus KA Halabi M Fuchs M Krüll M Engel J Wolff M Matejec R Langefeld TW Welters ID Menges T Dehne MG Sablotzki A Hempelmann G 《Amino acids》2005,29(3):289-300
Summary. The objective of this study was to determine the dose as well as duration of exposure-dependent effects of L-alanyl-L-glutamine,
arginine or taurine on polymorphonuclear neutrophil (PMN) free α-keto acid profiles and, in a parallel study, on PMN immune
functions. Exogenous L-alanyl-L-glutamine significantly increased PMN α-ketoglutarate, pyruvate PMN superoxide anion (O2−) generation, hydrogen peroxide (H2O2) formation and released myeloperoxidase (MPO) activity. Arginine also led to significant increases in α-ketoglutarate, pyruvate,
MPO release and H2O2 generation. Formation of O2− on the other hand was decreased by arginine. Incubation with taurine resulted in lower intracellular pyruvate and α-ketobutyrate
levels, decreased O2− and H2O2 formation and a concomitant significantly increased MPO activity. We therefore believe that considerable changes in PMN free-α-keto-acid
profiles, induced for example by L-alanyl-L-glutamine, arginine or taurine, may be one of the determinants in cell nutrition
that considerably modulates the immunological competence of PMN. 相似文献
11.
Taurine modulates kallikrein activity and glucose metabolism in insulin resistant rats 总被引:2,自引:0,他引:2
Summary. Taurine, a potent antioxidant has been reported to show an antidiabetic effect in streptozotocin-induced diabetes mellitus
in which the development of hyperglycemia results from the damage to β cells of pancreas by reactive oxygen species. In addition, taurine also increases the excretion of nitrite and enhances the
formation of kinins and would be expected to improve insulin resistance. The effect of taurine on insulin sensitivity was
examined in the high fructose-fed rats, an animal model of insulin resistance. Male Wistar rats of body weight 170–190 g were
divided into 4 groups: a control group and taurine-supplemented control group, taurine supplemented and unsupplemented fructose-fed
group. An intravenous glucose tolerance test (IVGTT) and a steady state plasma glucose level (SSPG) were performed before
the sacrifice. The fructose-fed rats displayed hyperglycemia and insulin resistance and they had a greater accumulation of
glycogen than did control rats. Hyperglycemia and insulin resistance were significantly lower in the taurine supplemented
fructose-fed group than in the unsupplemented fructose-fed group. Urinary kallikrein activity was higher in taurine-treated
animals than in the rats fed only fructose. The activity of membrane bound ATPases were significantly lower in fructose-fed
rats than in the control rats and were significantly higher in the taurine supplemented group than in the fructose-fed group.
Taurine effectively improves glucose metabolism in fructose-fed rats presumably via improved insulin action and glucose tolerance.
Received January 5, 2001 Accepted August 21, 2001 相似文献
12.
Summary. The effect of beta-alanine (β-Ala) alone or in combination with creatine monohydrate (Cr) on aerobic exercise performance
is unknown. The purpose of this study was to examine the effects of 4 weeks of β-Ala and Cr supplementation on indices of
endurance performance. Fifty-five men (24.5 ± 5.3 yrs) participated in a double-blind, placebo-controlled study and randomly
assigned to one of 4 groups; placebo (PL, n = 13), creatine (Cr, n = 12), beta-alanine (β-Ala, n = 14), or beta-alanine plus creatine (CrBA, n = 16). Prior to and following supplementation, participants performed a graded exercise test on a cycle ergometer to determine
VO2peak, time to exhaustion (TTE), and power output, VO2, and percent VO2peak associated with VT and LT. No significant group effects were found. However, within groups, a significant time effect was
observed for CrBa on 5 of the 8 parameters measured. These data suggest that CrBA may potentially enhance endurance performance. 相似文献
13.
Summary. Recent literature suggests that both caffeine and taurine can induce diuresis and natriuresis in rat and man. Although they
act via different cellular mechanisms, their diuretic actions might be additive. This is of considerable interest, as several
commercially available energy drinks contain both substances.
In this study we examined the possible diuretic effects of caffeine and taurine in a cross-over-design in which 12 healthy
male volunteers received each of 4 different test drinks (750 ml of energy drink containing 240 mg caffeine and 3 g taurine,
the three other test drinks either lacked caffeine, taurine or both) after restraining from fluids for 12 h.
Mixed model analyses demonstrated that urinary output and natriuresis were significantly increased by caffeine (mean differences
243 ml and 27 mmol; both p < 0.001) and that there were no such effects of taurine (mean differences 59 ml and −4 mmol). Additionally, urinary osmolarity
at baseline was significantly related to the urinary output (p < 0.001). Urine osmolarity values at baseline and in the 6 h urine collection did not differ significantly between treatments.
Taken together, our study demonstrates that diuretic and natriuretic effects of the tested energy drink were largely mediated
by caffeine. Taurine played no significant role in the fluid balance in moderately dehydrated healthy young consumers. Consequently,
the diuretic potential of energy drinks will not differ significantly from other caffeine containing beverages. 相似文献
14.
It has been reported that estrogen receptor-positive MCF-7 cells express TauT, a Na+-dependent taurine transporter. However, there is a paucity of information relating to the characteristics of taurine transport
in this human breast cancer cell line. Therefore, we have examined the characteristics and regulation of taurine uptake by
MCF-7 cells. Taurine uptake by MCF-7 cells showed an absolute dependence upon extracellular Na+. Although taurine uptake was reduced in Cl- free medium a significant portion of taurine uptake persisted in the presence of NO3
-. Taurine uptake by MCF-7 cells was inhibited by extracellular β-alanine but not by L-alanine or L-leucine. 17β-estadiol increased
taurine uptake by MCF-7 cells: the Vmax of influx was increased without affecting the Km. The effect of 17β-estradiol on taurine uptake by MCF-7 cells was dependent upon the presence of extracellular Na+. In contrast, 17β-estradiol had no significant effect on the kinetic parameters of taurine uptake by estrogen receptor-negative
MDA-MB-231 cells. It appears that estrogen regulates taurine uptake by MCF-7 cells via TauT. In addition, Na+-dependent taurine uptake may not be strictly dependent upon extracellular Cl-. 相似文献
15.
Guz G Oz E Lortlar N Ulusu NN Nurlu N Demirogullari B Omeroglu S Sert S Karasu C 《Amino acids》2007,32(3):405-411
Summary. Ischemia-reperfusion (I/R) injury is one of the most common causes of renal dysfunction. Taurine is an endogenous antioxidant
and a membrane-stabilizing, intracellular, free beta-amino acid. It has been demonstrated to have protective effects against
I/R injuries to tissues other than kidney. The aim of this study was to determine whether taurine has a beneficial role in
renal I/R injury. Forty Wistar-Albino rats were allocated into four groups as follows: sham, taurine, I/R, and I/R + taurine.
Taurine 7.5 mg/kg was given intra-peritoneally to rats in the groups taurine and I/R + taurine. Renal I/R was achieved by
occluding the renal arteries bilaterally for 40 min, followed by 6 h of reperfusion. Immediately thereafter, blood was drawn
and tissue samples were harvested to measure 1) serum levels of BUN and creatinine; 2) serum and/or tissue levels of malondialdehyde
(MDA), glutathione (GSH), glucose 6-phosphate dehydrogenase (G-6PD), 6-phosphogluconate dehydrogenase (6-PGD) and glutathione
reductase (GSH-red); 3) renal morphology; and 4) immunohistochemical staining for P-selectin. Taurine administration reduced
I/R-induced increases in serum BUN and creatinine, and serum and tissue MDA levels (p < 0.05). Additionally, taurine lessened
the reductions in serum and tissue glutathione levels secondary to I/R (p < 0.05). Taurine also attenuated histopathologic
evidence of renal injury, and reduced I/R-induced P-selectin immunoreactivity (p < 0.05). Overall, then, taurine administration
appears to reduce the injurious effects of I/R on kidney. 相似文献
16.
Summary. Many studies have suggested an antioxidant role for taurine, but few studies have directly measured its free radical scavenging
activity. The aim of the present study was to directly determine the action of taurine and taurine analogs to inhibit peroxynitrite-mediated
oxidation of dihydrorhodamine 123 (DHR) to rhodamine. Taurine was also tested to determine if it could attenuate the toxicity
of sodium nitroprusside (SNP) to neuronal cultures. Taurine at concentrations above 30 mM had a modest ability to inhibit
peroxynitrite formation derived from SIN-1. Hypotaurine could inhibit peroxynitrite formation from both SIN-1 (↓75%) and SNP
(↓50%) at 10 mM. Other taurine analogs (homotaurine, β-alanine & isethionic acid) slightly potentiated DHR oxidation by SIN-1. Short-term (1-hour) treatment of PC12 cultures with
either SNP (1–2 mM) or taurine (20–40 mM) appeared to induce cellular proliferation. In contrast, 24-hour treatment with SNP
(1 mM) induced cell death. Combination treatments with taurine and SNP appeared to interact in an additive fashion for both
cell proliferation and neurotoxic actions. It appears unlikely that taurine is a major endogenous scavenger of peroxynitrite.
Received May 9, 2000 Accepted June 13, 2000 相似文献
17.
Dietary taurine enhances cholesterol degradation and reduces serum and liver cholesterol concentrations in rats fed a high-cholesterol diet 总被引:1,自引:0,他引:1
Summary. The effect of taurine on hypercholesterolemia induced by feeding a high-cholesterol (HC) diet (10 g/kg) to rats was examined.
When taurine was supplemented to HC for 2 wk, serum total cholesterol significantly decreased and serum HDL-cholesterol increased
compared with the HC diet group. In the hypercholesterolemic rats fed the HC diet, the excretion of fecal bile acids and hepatic
cholesterol 7α-hydroxylase (CYP7A1) activity and its mRNA level increased significantly, and the supplementation of taurine further enhanced
these indexes, indicating an increase in cholesterol degradation. Agarose gel electrophoresis revealed that, in hypercholesterolemic
rats fed the HC diet, the serum level of the heavier VLDL increased significantly, but taurine repressed this increase and
normalized this pattern. Significant correlations were observed between the time-dependent increase of CYP7A1 gene expression
and the decrease of blood cholesterol concentration in rats fed the HC diet supplemented with taurine. These results suggest
that the hypocholesterolemic effects of taurine observed in the hypocholesterolemic rats fed the HC diet were mainly due to
the enhancement of cholesterol degradation and the excretion of bile acid.
Received December 4, 2001 Accepted January 2, 2002 Published online September 10, 2002
Acknowledgment This work was supported by a grant of Taisho Pharmaceutical Co., Ltd (Japan). We thank J. I. Gordon for their generous gifts
of cDNAs.
Authors' address: Dr. Hidehiko Yokogoshi, School of Food and Nutritional Sciences, The University of Shizuoka, Shizuoka 4228526, Japan, E-mail:
yokogosi@u-shizuoka-ken.ac.jp 相似文献
18.
The role of 3′,5′-cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), protein kinase C (PKC) and phosphatases
in the regulation of the taurine influx via the β-system in Ehrlich ascites tumor cells has been investigated. The taurine
uptake by the β-system in Ehrlich cells is inhibited when PKC is activated by phorbol 12-myristate 13-acetate (PMA) and when
protein phosphatases are inhibited by calyculin A (CLA). On the other hand, taurine uptake by the β-system is stimulated by
an increased level of cAMP or following addition of N6,2′-O-dibutyryl-3′,5′-cyclic adenosine monophosphate (dbcAMP). The effect of dbcAMP is partially blocked by addition of the
protein kinase inhibitor H-89, and suppressed in the presence of CLA. It is proposed that the β-system in the Ehrlich cells
exists in three states of activity: State I, where a PKC phosphorylation site on the transporter or on a regulator is phosphorylated and transport activity is low. State II, where the PKC phosphorylation site is dephosphorylated and transport activity is normal. State III, representing a state with high transport activity, induced by an elevated cellular cAMP level. Apparently, cAMP preferentially
stimulates taurine transport when the β-system is in State II.
Received: 8 September/Revised: 9 November 1995 相似文献
19.
Mühling J Burchert D Langefeld TW Matejec R Harbach H Engel J Wolff M Welters ID Fuchs M Menges T Krüll M Hempelmann G 《Amino acids》2007,33(3):511-524
Summary. We examined the effects of DON [glutamine-analogue and inhibitor of glutamine-requiring enzymes], alanyl-glutamine (regarding
its role in neutrophil immunonutrition) and alanyl-glutamine combined with L-NAME, SNAP, DON, β-alanine and DFMO on neutrophil
amino and α-keto acid concentrations or important neutrophil immune functions in order to establish whether an inhibitor of
•NO-synthase [L-NAME], an •NO donor [SNAP], an analogue of taurine and a taurine transport antagonist [β-alanine], an inhibitor
of ornithine-decarboxylase [DFMO] as well as DON could influence any of the alanyl-glutamine-induced effects. In summary,
irrespective of which pharmacological, metabolism-inhibiting or receptor-mediated mechanisms were involved, our results showed
that impairment of granulocytic glutamine uptake, modulation of intracellular glutamine metabolisation and/or de novo synthesis
as well as a blockade of important glutamine-dependent metabolic processes may led to significant modifications of physiological
and immunological functions of the affected cells. 相似文献
20.
Summary. The aim of the present study was to measure MPO activity in PMN leukocytes after endotoxin administration, and to compare
the levels of NO2
− competing with taurine for reaction with HOCl. Furthermore we aimed to determine TauCl levels, a product of MPO–H2O2–Halide system, and to evaluate anti-inflammatory properties of PMN in endotoxemia. In addition, our second objective was
to investigate the effect of taurine, an antioxidant amino acid, on anti-bactericidal and anti-inflammatory functions of PMN
after administration of endotoxin together with taurine.
All experiments were performed with four groups (control, taurine, endotoxemia, and taurine plus endotoxin) of ten guinea
pigs. After endotoxin administration (4 mg/kg), MPO activities increased and taurine levels decreased. Therefore levels of
TauCl, NO2
•− increased. We observed the effects of taurine as conflicting. When taurine was administrated alone (300 mg/kg), all of these
parameters decreased.
Consequently, we suggested that taurine is influential in infected subjects but not on healthy ones as an antioxidative amino
acid. In addition, we believe that in vivo effects of taurine may differ from those in vitro depending on its dosage. 相似文献