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Title
Improvement in cholesterol metabolism in mice given chronic treatment
of taurine and fed a high-fat diet.
Author
Murakami S; Kondo Ohta Y; Tomisawa K
Source
Life Sci, 1999, 64:1, 83-91
Abstract
The effects of chronic treatment of taurine on hypercholesterolemia
and atherosclerosis were examined in C57BL/6J mice fed a high-fat
diet containing 15% fat and 1.25% cholesterol. Taurine was dissolved
in drinking water at 1% (w/v) and was given to mice ad libitum
during 6 months-feeding of a high-fat diet. Hypercholesterolemia
occurred and lipid accumulation on the aortic valve was evident.
Taurine treatment lowered serum LDL + VLDL cholesterol by 44%
in mice fed a high-fat diet, while it elevated serum HDL cholesterol
by 25%. As a result, the atherogenic index, the ratio of HDL
to LDL + VLDL was markedly improved. Cholesterol content in the
liver also decreased by 19% with taurine. Similar tendencies
were seen in mice fed regular chow, but the changes were not
significant. The area of aortic lipid accumulation, which served
as an index of atherosclerosis, was reduced by 20% with taurine.
In the liver, taurine doubled the activity of cholesterol 7alpha-hydroxylase.
These observations, together with prior findings, suggest that
the cholesterol-lowering action of taurine may relate to the
increased conversion of cholesterol to bile acids via stimulation
of cholesterol 7a-hydroxylase activity. Thus, chronic treatment
of high-fat mice with taurine improves the abnormal profile of
the serum lipoproteins, and thereby retards the progression of
atherosclerosis.
Title
Protective effect of taurine on TNBS-induced inflammatory bowel
disease in rats.
Author
Son MW; Ko JI; Doh HM; Kim WB; Park TS; Shim MJ; Kim BK
Source
Arch Pharm Res, 1998 Oct, 21:5, 531-6
Abstract
We had previously reported that the protective effect of taurine
against indomethacin-induced gastric mucosal injury was due to
its antioxidant effects, which inhibited lipid peroxidation and
neutrophil activation. In this study, we examined the effect
of taurine on reducing the inflammatory parameters of trinitrobenzene
sulfonic acid (TNBS)-induced inflammatory bowel disease (IBD)
in rats. In order to induce IBD, ethanolic TNBS was given to
rats intracolonically. Then they received 500 mg/kg/day of taurine
orally and were sacrificed one week after IBD induction. While
ulceration and inflammation of distal colon with formation of
granuloma in the vehicle-treated IBD rats two days after administration
of TNBS were observed, treatment with taurine ameliorated colonic
damage and decreased the incidence of diarrhea and adhesion.
Also, colon weight as an index of tissue edema, which was markedly
increased in the IBD rats, became significantly lower after taurine
treatment. Myeloperoxidase (MPO) activity in the vehicle-treated
IBD rats was substantially increased, compared with that of normal
control. The taurine-treated animals significantly reduced MPO
activity (35% lower) when compared with that of the vehicle-treated
animals. Taurine treatment decreased both basal and formyl-methionyl
leucyl phenylalanine-stimulated reactive oxygen generation from
colonic tissue in the IBD rats. These results suggest that the
administration of taurine reduce the inflammatory parameters
in this IBD rat model by increasing defending capacity against
oxidative damage.
Title
An N-acyl glycyltaurine conjugate of deoxycholic acid in the
biliary bile acids of the rabbit.
Author
Hagey LR; Schteingart CD; Rossi SS; Ton Nu HT; Hofmann AF
Source
J Lipid Res, 1998 Nov, 39:11, 2119-24
Abstract
jj biliary bile acid composition of the adult and neonatal domestic
rabbit, as well as that of the adult brush rabbit, was characterized.
In adult domestic rabbits, the dominant bile acid present was
deoxycholic acid (88% of total bile acids), a secondary bile
acid formed by the bacterial 7-dehydroxylation of cholic acid.
Although most of the bile acids present were conjugated with
glycine, two exceptions were observed. About 3% of deoxycholic
acid was conjugated, in N-acyl linkage, with glycyl-taurine.
Chenodeoxycholic acid, which composed <1% of wile acids, was
conjugated solely with taurine. The bile of neonatal rabbits
contained a greater percentage of primary bile acids, and bile
acids were conjugated to a much greater extent with taurine.
The adult brush rabbit had a bile acid composition similar to
that of the domestic rabbit, but about one-third of all bile
acids were conjugated with taurine. In addition, lithocholic
acid was present as its sulfated amidate, whereas in the domestic
rabbit, lithocholic acid was conjugated solely with glycine.
The biliary bile acid composition of rabbits appears to be unique
both in terms of the predominant steroid moiety, as well as in
the modes of conjugation.
Title
Immunonutrition: the role of taurine.
Author
Redmond HP; Stapleton PP; Neary P; Bouchier Hayes D
Source
Nutrition, 1998 Jul, 14:7-8, 599-604
Abstract
Taurine is a sulfonated beta amino acid derived from methionine
and cysteine metabolism. It is present in high concentrations
in most tissues and in particular in proinflammatory cells such
as polymorphonuclear phagocytes. Initial investigation into the
multifaceted properties of this non-toxic physiologic amino acid
revealed a link between retinal dysfunction and dietary deficiency.
Since then a role for this amino acid has been found in membrane
stabilization, bile salt formation, antioxidation, calcium homeostasis,
growth modulation, and osmoregulation. Our own group has demonstrated
a key role for taurine in modulation of apoptosis in a variety
of cell types. This review summarizes our current knowledge of
taurine in nutrition, host proinflammatory cell homeostasis,
therapeutic applications, and its potential immunoregulatory
properties. It is our belief that taurine, similar to arginine
and glutamine, is now more than worthy of critical clinical analysis.
Title
The role of taurine in osmotic, mechanical, and chemical protection
of the retinal rod outer segments.
Author
Petrosian AM; Haroutounian JE
Source
Adv Exp Med Biol, 1998, 442:, 407-13
Abstract
The ability of the photoreceptor cell to resist osmotic stress
was examined by incubating isolated frog retina in medium of
varying osmolality. An electron microscopic analysis of the rod
outer segment following a severe hypoosmotic insult revealed
connections between adjacent disks and between disk rims and
the plasma membrane, which presumably provide mechanical stability
to the rod outer segment. One surprising result was the extent
of the damage incurred by the electrical signaling pathway of
the photoreceptor cells subjected to a 50 mOsm insult; only the
distal P111 component of the ERG remained unaffected. Thus, the
rod outer segment is particularly resistant to osmotic-induced
injury, presumably because of the effective osmoregulatory actions
of taurine. Incubation of retina with tauret, retinylidentaurine,
uncovered rose-like hexagonal structures on the surface of the
rod outer segment. These structures purportedly consist of connections
between disk rims and the plasma membrane of the rod outer segments.
Based on the influence of tauret, it is likely that the calcium
dependence of these channels is selective for retinoids. These
data are discussed relative to taurine's role in the process
of rhodopsin regeneration and in the protection of the rod outer
segments against osmotic, mechanical and light induced damage.
Title
Regulation of taurine biosynthesis and its physiological significance
in the brain.
Author
Wu JY; Tang XW; Schloss JV; Faiman MD
Source
Adv Exp Med Biol, 1998, 442:, 339-45
Abstract
Cysteine sulfinic acid decarboxylase (CSAD), the rate-limiting
enzyme in taurine biosynthesis, was found to be activated under
conditions that favor protein phosphorylation and inactivated
under conditions favoring protein dephosphorylation. Direct incorporation
of 32P into purified CSAD has been demonstrated with [gamma 32P]ATP
and PKC, but not PKA. In addition, the 32P labeling of CSAD was
inhibited by PKC inhibitors suggesting that PKC is responsible
for phosphorylation of CSAD in the brain. Okadaic acid had no
effect on CSAD activity at 10 microM suggesting that protein
phosphatase-2C (PrP-2C) might be involved in the dephosphorylation
of CSAD. Furthermore, it was found that either glutamate- or
high K(+)-induced depolarization increased CSAD activity as well
as 32P-incorporation into CSAD in neuronal cultures, supporting
the notion that the CSAD activity is endogenously regulated by
protein phosphorylation in the brain. A model to link neuronal
excitation, phosphorylation of CSAD and increase in taurine biosynthesis
is proposed.
Title
Effect of taurine on toxicity of copper in rats.
Author
Hwang DF; Wang LC; Cheng HM
Address
Department of Marine Food Science, National Taiwan Ocean University,
Keelung, ROC. Source
Food Chem Toxicol, 1998 Mar, 36:3, 239-44
Abstract
An attempt was made to study the effect of taurine on the toxicity
of copper in male Wistar rats. The rats were divided into eight
groups and fed different diets with or without supplement of
5% taurine and 150-600 ppm copper for 2 months. It was found
that the levels of copper and malondialdehyde (MDA) in the liver,
and the activities of aspartate transaminase (AST) and alanine
transaminase (ALT) in the plasma of rats were increased with
the increasing dose of copper. However, the levels of copper
and MDA, and the enzyme activities of AST and ALT in the rats
fed with supplement of taurine were significantly lower than
in the rats fed without supplement of taurine. The level of copper
in the faeces of rats treated with taurine and copper was higher
than that of rats treated with copper alone. It indicated that
taurine might play a role in reducing the toxic effect of copper
in rats.
Title
Therapeutic applications of taurine.
Author
Birdsall TC
Source
Altern Med Rev, 1998 Apr, 3:2, 128-36
Abstract
Taurine is a conditionally-essential amino acid which is not
utilized in protein synthesis, but rather is found free or in
simple peptides. Taurine has been shown to be essential in certain
aspects of mammalian development, and in vitro studies in various
species have demonstrated that low levels of taurine are associated
with various pathological lesions, including cardiomyopathy,
retinal degeneration, and growth retardation, especially if deficiency
occurs during development. Metabolic actions of taurine include:
bile acid conjugation, detoxification, membrane stabilization,
osmoregulation, and modulation of cellular calcium levels. Clinically,
taurine has been used with varying degrees of success in the
treatment of a wide variety of conditions, including: cardiovascular
diseases, hypercholesterolemia, epilepsy and other seizure disorders,
macular degeneration, Alzheimer's disease, hepatic disorders,
alcoholism, and cystic fibrosis.
Title
Taurine status in cats is not maintained by dietary cysteinesulfinic
acid.
Author
Edgar SE; Kirk CA; Rogers QR; Morris JG
Source
J Nutr, 1998 Apr, 128:4, 751-7
Abstract
Endogenous synthesis of taurine by cats is limited. Putative
precursors of taurine, cysteinesulfinic acid and cysteic acid,
were fed to cats to determine whether they were utilized. Groups
of five cats were depleted of taurine by a resin (Colestipol(R))
diet, then given 6 dietary treatments containing (g/kg diet):
0.0, 0.4, or 0.8 taurine; or 0.98 or 1.96 cysteinesulfinic acid,
or 0.4 taurine + 1.0 cysteic acid for 12 wk. Plasma and whole
blood taurine concentrations and body weights were measured weekly.
Concentration of taurine in semitendinosus muscle was measured
initially, after 2 wk of taurine depletion (after resin-diet),
and monthly thereafter. The resin diet decreased concentrations
of taurine in plasma, whole blood, and muscle to 0.20, 0.49,
and 0.37 of initial values, respectively. Cysteinesulfinic acid
diets resulted in no significant (P > 0.05) increase in the
concentration of taurine in plasma, whole blood, or muscle, and
no increased excretion of cysteinesulfinate or taurine in urine
or feces. Cats fed the diets containing 1.0 g cysteic acid +
0.4 g taurine, or 0.8 g taurine/kg diet had similar concentrations
of taurine in plasma, whole blood, and muscle. Aminotransferase
activity for cysteinesulfinic acid in the liver and intestinal
mucosa of cats and rats was higher than that for aspartic or
cysteic acids. Transamination of dietary cysteinesulfinic acid
to beta-sulfinylpyruvate (which spontaneously decomposes), rather
than decarboxylation is postulated as the basis for no detectable
conversion to taurine. In contrast, cysteic acid is reversibly
transaminated to beta-sulfopyruvate which is stable and thereby
is a precursor for taurine in cats.
Title
Effects of some sulfur-containing antioxidants on lead-exposed
lenses.
Author
Neal R; Cooper K; Kellogg G; Gurer H; Ercal N
Source
Free Radic Biol Med, 1999 Jan, 26:1-2, 239-43
Abstract
Lead (Pb) is known to negatively affect glutathione (GSH) metabolism
in the lens. The present study examined the effects of Captopril,
Taurine, and alpha-Lipoic acid on the Pb-induced GSH depletion
and lipid peroxide increase in the lenticular system. Captopril
administration returned the GSH, cysteine (CYS), and malondialdehyde
(MDA) levels to near normal. Following Taurine administration
the GSH, CYS and MDA levels were intermediate between the control
group and the Pb group levels. Alpha-Lipoic acid administration,
however, only increased the CYS levels. No significant changes
in oxidized glutathione (GSSG) levels were observed in any treatment
group. |
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