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1.
Consequences of renal mass reduction on amino acid and biogenic amine levels in nephrectomized mice 总被引:2,自引:0,他引:2
Summary. Amino acid and biogenic amine changes were investigated in nephrectomized mice ten days postsurgery. Uremic mice exhibited
changes in amino acid concentrations in plasma, urine and brain. Particularly plasma methionine, citrulline and arginine levels
were significantly enhanced in nephrectomized mice compared to controls whereas serine was decreased. Urinary excretion of
methionine, citrulline and alanine was higher in nephrectomized mice compared to controls whereas many amino acids were increased
in brain of nephrectomized mice. Brain and urinary amino acid changes were more pronounced in the 75% than in the 50% nephrectomized
mice. Brain norepinephrine and dopamine and its metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid were significantly
increased whereas serotonin was decreased comparing the 75% nephrectomized mice to the sham-operated mice. This study demonstrates
that at very early stages of renal insufficiency, specific amino acid and biogenic amine changes occur in plasma, urine and
brain. These alterations might depend qualitatively and quantitatively on the degree of functional renal mass reduction.
Received April 5, 1999 相似文献
2.
The purpose of this study was to determine the effects of a high protein diet on glucose tolerance. Nine Sprague Dawley rats received a high protein (HP) diet (65% protein, 35% fat) and eight rats consumed a standard chow (SC) diet over eight weeks. Oral glucose tolerance tests (OGTT) were performed at the end of the third and the seventh week. The diet did not effect glucose tolerance in the first (SC=10357+/-294 mg/dl/120 min; HP=9846+/-300 mg/dl/120 min) or the second OGTT (SC=10134+/-395 mg/dl/120 min; HP=10721+/-438 mg/dl/120 min) as reflected by the area under the glucose concentration curve. Similarly, the area under the insulin concentration curve was not effected by the high protein diet during the first (SC=49.21+/-8.46 ng/ml/120 min; HP=41.75+/-10.54 ng/ml/120 min) or the second OGTT (SC=96.63+/-13.68 ng/ml/120 min; HP=92.77+/-17.44 ng/ml/120 min). The high protein diet group experienced a delayed glucose response for the first (SC=30 min at 112+/-7 mg/dl; HP=60 min at 101+/-5 mg/dl) and second OGTT (SC=15 min at 117+/-5 mg/dl; HP=60 min at 95+/-7 mg/dl). Body mass increased to the same extent in each diet group from the initial to final weighing (SC=159+/-2 g to 254+/-7 g; HP=157+/-2 g to 242+/-7 g). Despite a delay in peak glucose response, these findings suggest that glucose tolerance and body mass were neither adversely nor positively affected by a high protein diet. 相似文献
3.
C. P. McPhee P. C. Trappett 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1987,73(6):926-931
Summary Two lines of mice were selected for high post-weaning weight gain (3 to 6 weeks) adjusted for 3 week weight. One line (F) was grown on freely available food and the other (S) on a feeding scale set at the same level for all mice. Food intake of the S line averaged 80% of the F line. The realised heritabilities after 6 generations of selection were 0.38±0.06 and 0.33±0.07 for the F and S lines, respectively. In generation 7, mice from the F and S lines and from an unselected control line (C) were compared on both free and set levels of feeding from 3 weeks to 9 weeks of age. Measurements taken were growth rate, appetite, food conversion efficiency (weight gain/food intake) and body composition (fat, protein, ash, water). The F and S lines grew more rapidly and efficiently than the C line on both levels of feeding, each line performing best on the level of feeding on which it was selected. The average genetic correlation between growth rates of the same line on the two feeding levels was 0.54±0.10. The F line grew 19% faster and was 9% more efficient than the S line on free feeding but the S line grew 15% faster and was 15% more efficient than the F line on set feeding. Relative to the C line, food intake per day on free feeding was 4% higher in the F line and 6% lower in the S line. There was no difference between the lines in food intake/g body weight. The rate of deposition of all body components increased in both selection lines. In the F, S and C lines respectively, efficiencies of gains in body components (102x gain/food) were 1.79, 1.31 and 1.06 for fat, 1.53, 1.63 and 1.22 for protein and 5.88, 6.45 and 4.98 for protein + water. Apparently energy lost as heat was reduced in both the F and S lines. The partitioning of energy retained was altered in favour of more fat in the F line and more protein in the S line. 相似文献
4.
Summary. There are no reliable mean values of NG-monomethylarginine (NMMA) in blood and urine of patients with renal insufficiency available in the literature. Therefore
we investigate whether the NMMA levels are changed in blood and urinary excretion of nondialysed and dialysed patients with
chronic renal insufficiency to evaluate whether NMMA may reach sufficiently increased concentrations in blood of the patients
to exert toxic biological activity.
In nondialysed as well as in dialysed patients we find no significant difference in serum concentration of NMMA between patients
and controls. In nondialysed patients (all with a residual creatinine clearance lower than 15 ml/min), we find 94.5 ± 26.1 nM
(mean ± SD) versus 94.6 ± 19.5 nM in controls. Similar levels are found in serum of haemodialysed patients (each with serum
creatinine levels >700 μM): 83.0 ± 20.2 nM. The urinary excretion of NMMA in nondialysed patients is also not significantly different from the excretion
of controls: 123 ± 110 in patients versus 157 ± 117 nmol/24 hrs in controls. Furthermore, the clearance of NMMA is much lower
compared to the clearance of the dimethylarginine derivatives.
Based on the literature, the low nanomolar levels of NMMA found in blood of patients with renal insufficiency do not support
the statement that NMMA proper may act as a uremic toxin.
Received April 3, 2002 Accepted October 7, 2002 Published online January 20, 2003
Acknowledgements We thank the University of Antwerp, FWO (Fonds voor Wetenschappelijk Onderzoek) (G.0027.97 and G.0394.00), the Born-Bunge
Foundation, the OCMW Medical Research Foundation and Neurosearch Antwerp for the financial support.
Authors' address: Bart Marescau, Laboratory of Neurochemistry and Behaviour, UIA T504, University of Antwerp, Universiteitsplein 1, B-2610
Wilrijk, Belgium, Fax: 00 32 3 8202618; E-mail: bartold.marescau@ua.ac.be 相似文献
5.
6.
Plasma lactate, GH and GH-binding protein levels in exercise following BCAA supplementation in athletes 总被引:4,自引:0,他引:4
Summary. Branched chain amino acids (BCAA) stimulate protein synthesis, and growth hormone (GH) is a mediator in this process. A pre-exercise
BCAA ingestion increases muscle BCAA uptake and use. Therefore after one month of chronic BCAA treatment (0.2 g kg−1 of body weight), the effects of a pre-exercise oral supplementation of BCAA (9.64 g) on the plasma lactate (La) were examined
in triathletes, before and after 60 min of physical exercise (75% of VO2max). The plasma levels of GH (pGH) and of growth hormone binding protein (pGHBP) were also studied. The end-exercise La of
each athlete was higher than basal. Furthermore, after the chronic BCAA treatment, these end-exercise levels were lower than
before this treatment (8.6 ± 0.8 mmol L−1 after vs 12.8 ± 1.0 mmol L−1 before treatment; p < 0.05 [mean ± std. err.]). The end-exercise pGH of each athlete was higher than basal (p < 0.05). Furthermore,
after the chronic treatment, this end-exercise pGH was higher (but not significantly, p = 0.08) than before this treatment
(12.2 ± 2.0 ng mL−1 before vs 33.8 ± 13.6 ng mL−1 after treatment). The end-exercise pGHBP was higher than basal (p < 0.05); and after the BCAA chronic treatment, this end-exercise
pGHBP was 738 ± 85 pmol L−1 before vs 1691 ± 555 pmol L−1 after. pGH/pGHBP ratio was unchanged in each athlete and between the groups, but a tendency to increase was observed at end-exercise.
The lower La at the end of an intense muscular exercise may reflect an improvement of BCAA use, due to the BCAA chronic treatment.
The chronic BCAA effects on pGH and pGHBP might suggest an improvement of muscle activity through protein synthesis.
Received January 5, 1999 / Accepted June 17, 1999 相似文献
7.
Summary. Taurine (2-aminoethane sulphonic acid), a sulphur-containing beta amino acid, is the most prevalent free intracellular amino acid in many human and animal tissues. Vitamin C metabolism is also fluenced by sulphur-containing amino acids. The aim of this study is to investigate the effect of taurine administration on the vitamin C levels of plasma and several tissues (brain, liver, kidneys) in mice with incisional skin wounds. Animals were divided into two as control and taurine groups. Taurine was freshly dissolved in sterile saline and administered daily (60µl, ip) for five days in the taurine group. At the end of the fifth day, the animals were killed by decapitation. The brain, liver and kidneys were immediately removed. Vitamin C levels were measured in plasma and several tissues. The administration of taurine had no effect on the plasma vitamin C levels (P>0.05) but significantly increased in liver and kidneys (P<0.001). In conclusion, taurine may affect the vitamin C metabolism in tissues by different mechanisms. 相似文献
8.
Hoeks J Hesselink MK Sluiter W Schaart G Willems J Morrisson A Clapham JC Saris WH Schrauwen P 《FEBS letters》2006,580(5):1371-1375
Uncoupling protein-3 (UCP3) has been suggested to protect against lipid-induced oxidative damage. Therefore, we studied intramuscular lipid peroxide levels and high-fat diet induced alterations in muscle lipid metabolism of UCP3-ablated mice. UCP3-/- mice showed approximately 3-fold higher levels of intramuscular lipid peroxides upon standard chow feeding, compared to wild-type littermates. Remarkably, this difference was no longer apparent on the high-fat diet. However, upon high-fat feeding, intramuscular triacylglycerol levels were approximately 50% lower in UCP3-/- mice, in comparison to UCP3+/+ animals. Succinate dehydrogenase activity, and total protein content of the muscle fatty acid transporter FAT/CD36 were however similar between UCP3-/- and UCP3+/+ mice. 相似文献
9.
This study investigated the effect of Cheonggukjang on mRNA levels of hepatic acyl-CoA synthase (ACS), carnitine palmitoyltransferase I (CPT-I), acyl-CoA oxidase (ACO) and uncoupling protein 2 (UCP2), and on serum lipid profiles in C57BL/6J mice. Thirty male C57BL/6J mice were divided into three groups; normal diet (ND), high fat diet (HD) and high fat diet with 40% Cheonggukjang (HDC). Energy intake was significantly higher in the HDC group than in the ND and HD groups. The HDC group normalized in weight gain, epididymal and back fat (g/100 g) accumulation which are increased by high fat diet. Serum concentrations of triglyceride and total cholesterol in the HDC were significantly lower than those in the HD group. These results were confirmed by hepatic mRNA expression of enzymes and protein (ACS, CPT-1, ACO, UCP2) which is related with lipid metabolism by RT-PCR. Hepatic CPT-I, ACO and UCP2 mRNA expression was increased by Cheonggukjang supplementation. We demonstrated that Cheonggukjang supplement leads to increased mRNA expressions of enzymes and protein involved in fatty acid oxidation in liver, reduced accumulation of body fat and improvement of serum lipids in high fat diet fed mice. 相似文献
10.
Up-regulation of ADRP in fatty liver in human and liver steatosis in mice fed with high fat diet 总被引:4,自引:0,他引:4
Motomura W Inoue M Ohtake T Takahashi N Nagamine M Tanno S Kohgo Y Okumura T 《Biochemical and biophysical research communications》2006,340(4):1111-1118
The present study was performed to examine a role of adipose differentiation-related protein (ADRP) in the process of liver steatosis. Immunohistochemical findings indicated that ADRP expression is increased in the hepatocytes in patients with fatty liver when compared with normal liver. ADRP expression is localized in the surface of lipid droplets in the hepatocytes. Increased expression of ADRP mRNA and protein was similarly observed in fatty liver in ob/ob mice and the liver steatosis induced by high fat diet in mice. The up-regulation of ADRP mRNA and protein in the liver by high fat diet was identified in the surface of lipid droplets in a time-dependent manner. Recent studies demonstrated that up-regulation of PPARgamma in the hepatocytes is deeply involved in liver steatosis. To clarify whether ADRP expression is increased by PPARgamma activation in hepatocytes, we examined the effect of a PPARgamma ligand, troglitazone, on ADRP mRNA expression in HepG2 cells. ADRP mRNA expression was increased by troglitazone in dose- and time-dependent manners. All these results suggest that ADRP is up-regulated in liver steatosis in human and mice, and that high fat diet increases expression of ADRP through PPARgamma activation, followed by induction of liver steatosis. 相似文献
11.
M. C. Cowan 《Plant and Soil》1979,51(2):279-282
Summary When nitrogen fixation in peas was partially replaced by nitrate assimilation as the source of nitrogen, an increase was found in the amount of soluble nitrogen that could be extracted from the fruits of the plants, and within this soluble fraction, increases were found in the levels of some of the acidic amino acids. Levels of protein amino acids in the peas were generally unaffected by the type of nitrogen source except for the level of aspartic acid which was about 20 per cent lower in peas supplied with nitrate. No differences were found in the proportions of the essential amino acids. 相似文献
12.
Defolliculated fully grown oocytes of Xenopus laevis were treated with cytochalasin D (10 micrograms/ml) and their protein synthesis was studied by labelling with S-35 methionine. This treatment brought about an alteration in pigment pattern as well as a reduction in amino acid uptake by the oocytes. However, the radioactive amino acid taken by cytochalasin-treated oocytes was incorporated into protein in the same proportion as in untreated oocytes. These results suggested that subcortical pigment distribution and amino acid uptake in fully grown oocytes were microfilament-dependent processes, whereas protein synthesis in the oocyte was not. 相似文献
13.
The hypocholesterolemic effect of taurine was examined in mice fed a high-cholesterol diet containing 1% cholesterol and 0.25% sodium cholate. Male C57BL/6 mice were divided into 3 groups: control group (HC), 1% taurine-supplemented group (HCT+), and taurine-deficient group (HCT-) produced by supplying 0.5% guanidinoethyl sulfonate (GES) solution ad libitum instead of water. After they were fed with the respective diet or drinking water for 4 weeks, the liver taurine level was reduced 80% in the HCT- group compared with that in the HC group, although there was no difference in the serum taurine amount between the two groups. The formation ratio of cholesterol gallstones increased from 71% to 100% by taurine deficiency, and decreased to 0% by taurine supplementation. Compared with the HC group, serum and liver cholesterol significantly decreased, and the excretion of fecal bile acid notably rose in the HCT+ group but tended to lower in the HCT- group. There were no differences in LDL receptor protein level among the three groups. In the subsequent experiment, triglycerides (TG) secretion rate was determined and found to be significantly suppressed by taurine supplementation. In conclusion, it is suggested that taurine does not up-regulate LDL receptor protein level, and the decrease in cholesterol in the circulation is mainly due to its suppressive effect on TG secretion from the liver. 相似文献
14.
P. G. Petronini A. E. Caccamo R. R. Alfieri M. A. Bonelli A. F. Borghetti 《Amino acids》2001,20(4):363-380
Summary. In 3T3 cells temperatures higher than physiological stimulated amino acid transport activity in a dose-dependent manner up to 44°C. However, the temperature increase did not induce widespread transport increase of all other nutrients tested. The activities of both amino acid transport systems A and ASC were enhanced within a few minutes following cell exposure to increased temperature. The maintenance of this effect required continuous exposure of the cells to hyperthermia. Kinetic analysis indicated that the stimulation of the activity of transport System A occurred through a mechanism affecting Vmax rather than Km. The continuous presence of cycloheximide did not prevent the transport changes induced by hyperthermia. These results suggest that the increased amino acid uptake reflects an activation or relocation of existing amino acid transport proteins. During the hyperthermic treatment, the content of ninhydrin-positive substances (NPS), mostly amino acids, increased within the cells and the accumulation of these compatible osmolytes was parallelled by an increase in cell volume. The withdrawal of amino acids from the culture medium immediately before and during the shock phase counteracted the increase and reduced the NPS content but did not prevent the increase in amino acid transport, the cell swelling and the induction of the heat shock response. Received June 30, 1999 Accepted July 27, 2000 相似文献
15.
Some hydrophobic polypeptides known as thermal proteins have been found to have neurotrophic effects. Thermal proteins were synthesized from aspartic acid, glutamic acid, proline, and tryptophan. Two hydrophobic and one nonhydrophobic polymers were injected intracerebroventricularly into brains of mice after partial training on footshock avoidance run in a T-maze. When retention was tested 1 week later, the hydrophobic polymers enhanced retention while the nonhydrophobic polymer did not. Thermal proteins exhibiting hydrophobicity and having neurotrophic effects may aid in altering synaptic connections by facilitating cell recognition. 相似文献
16.
Summary. This paper examines a unique hypothesis regarding an important role for taurine in renal development. Taurine-deficient neonatal
kittens show renal developmental abnormalities, one of several lines of support for this speculation. Adaptive regulation
of the taurine transporter gene is critical in mammalian species because maintenance of adequate tissue levels of taurine
is essential to the normal development of the retina and the central nervous system. Observations of the remarkable phenotypic
similarity that exists between children with deletion of bands p25-pter of chromosome 3 and taurine-deficient kits led us
to hypothesize that deletion of the renal taurine transporter gene (TauT) might contribute to some features of the 3p-syndrome.
Further, the renal taurine transporter gene is down-regulated by the tumor suppressor gene p53, and up-regulated by the Wilms
tumor (WT-1) and early growth response-1 (EGR-1) genes. It has been demonstrated using WT-1 gene knockout mice that WT-1 is
critical for normal renal development. In contrast, transgenic mice overexpressing the p53 gene have renal development defects,
including hypoplasia similar to that observed in the taurine-deficient kitten. This paper reviews evidence that altered expression
of the renal taurine transporter may result in reduced intracellular taurine content, which in turn may lead to abnormal cell
volume regulation, cell death and, ultimately, defective renal development.
Received January 25, 2000/Accepted January 31, 2000 相似文献
17.
Diamide directly added to renal cortical slices inhibits the uptake of amino acids. Steady-state kinetic analysis indicates an inhibition of α-amino acid influx without effect on efflux. The effect could be reversed by addition of pyruvate to the incubation medium. Although there was a good correlation of the transport effect of diamide with its ability to decrease cellular reduced glutathione concentration, there did not appear to be a necessary connection between them. This was shown by the fact that renal cortical slices stored at 4°C have no alteration in amino acid uptake despite the fact that GSH concentration is as low as that seen with diamide. Diamide was shown to have a direct effect on the uptake of glycine by isolated renal brush border membrane vesicles. 相似文献
18.
Summary. We have shown that urinary urea excretion increased in rats fed a low quality protein. The purpose of present study was to determine whether an addition of dietary limiting amino acids affected urea synthesis in rats fed a low gluten diet. Experiments were done on three groups of rats given diets containing 10% gluten, 10% gluten+0.5% L-lysine or 10% gluten+0.5% L-lysine, 0.2% L-threonine and 0.2% L-methionine for 10d. The urinary excretion of urea, and the liver concentrations of serine and ornithine decreased with the addition of dietary L-lysine, L-threonine and L-methionine. The fractional and absolute rates of protein synthesis in tissues increased with the treatment of limiting amino acids. The activities of hepatic urea-cycle enzymes was not related to the urea excretion. These results suggest that the addition of limiting amino acids for the low gluten diet controls the protein synthesis in tissues and hepatic ornithine and decline urea synthesis. 相似文献
19.
Summary. Three models representing different separations of amino acid sources were used to simulate experimental specific radioactivity data and to predict protein fractional synthesis rate (FSR). Data were from a pulse dose of 14C-U Leu given to a non-growing 20 g mouse and a flooding dose of 3H Phe given to a non-growing 200 g rat. Protein synthesis rates estimated using the combined extracellular and intracellular (Ec + Ic) source pool and extracellular and plasma (Ec + Pls) source pool mouse models were 78 and 120% d−1 in liver, 14 and 16% d−1 in brain and 15 and 14% d−1 in muscle. Predicted protein synthesis rates using the Ec + Ic, Ec + Ic + Tr (combined extracellular, intracellular and aminoacyl tRNA source pool) and Ec + Pls rat models were 57, 3.4 and 57% d−1 in gastrocnemius, 58, 71 and 62% d−1 in gut, 8.3, 8.4 and 7.9% d−1 in heart, 32, 23 and 25% d−1 in kidney, 160, 90 and 80% d−1 in liver, 57, 5.5 and 57% d−1 in soleus and 56, 3.4 and 57% d−1 in tibialis. The Ec + Ic + Tr model underestimated protein synthesis rates in mouse tissues (5.0, 27 and 2.5% d−1 for brain, liver and muscle) and rat muscles (3.4, 5.5 and 3.4% d−1 for gastrocnemius, soleus and tibialis). The Ec + Pls model predicted the mouse pulse dose data best and the Ec + Ic model predicted the rat flooding dose data best. Model predictions of FSR imply that identification and separation of the source specific radioactivity is critical to accurately estimate FSR. Received June 11, 2000 Accepted September 26, 2000 相似文献