Taurine AND Ca homeostasis

AIMS: Despite its high concentration in pancreatic islets of Langerhans and broad range of antihyperglycemic effects, the route facilitating the import of dietary taurine into pancreatic β-cell and mechanisms underlying its insulinotropic activity are unclear. We therefore studied the impact of taurine on beta-cell function, alongside that of other small neutral amino acids, L-alanine and L-proline. MAIN METHODS: Pharmacological profiling of insulin secretion was conducted using clonal BRIN BD11 β-cells, the impact of taurine on the metabolic fate of glucose carbons was assessed using NMR and the findings were verified by real-time imaging of Ca2+ dynamics in the cytosol of primary mouse and human islet beta-cells...

Hepatobiliary involvement is a hallmark in cystic fibrosis (CF), as the causative CF Transmembrane Conductance Regulator (CFTR) defect is expressed in the biliary tree. However, bile acid (BA) compositions in regard to pancreatic insufficiency, which is present at an early stage in about 85% of CF patients, have not been satisfactorily understood. We assess the pattern of serum BAs in people with CF (pwCF) without CFTR modulator therapy in regard to pancreatic insufficiency and the CFTR genotype. In 47 pwCF, 10 free and 12 taurine- and glycine-conjugated BAs in serum were prospectively assessed...

Background & Aims: Increased plasma ammonia concentration and consequent disruption of brain energy metabolism could underpin the pathogenesis of hepatic encephalopathy (HE). Brain energy homeostasis relies on effective maintenance of brain oxygenation, and dysregulation impairs neuronal function leading to cognitive impairment. We hypothesised that HE is associated with reduced brain oxygenation and we explored the potential role of ammonia as an underlying pathophysiological factor...

Extibacter muris is a newly described mouse gut bacterium which metabolizes cholic acid (CA) to deoxycholic acid (DCA) via 7α-dehydroxylation. Although bile acids influence metabolic and inflammatory responses, few in vivo models exist for studying their metabolism and impact on the host. Mice were colonized from birth with the simplified community Oligo-MM12 with or without E. muris . As the metabolism of bile acids is known to affect lipid homeostasis, mice were fed either a low- or high-fat diet for eight weeks before sampling and analyses targeting the gut and liver...

ETHNOPHARMACOLOGICAL RELEVANCE: Accumulation of hepatic lipid promotes systemic metabolic dysfunction and results in fatty liver. Our previous studies have shown that the alkaloids of Dendrobium nobile Lindl. (DNLA) could regulate the lipid metabolism gene expression in livers of mice. However, the protective effects on hepatic lipid homeostasis and the underlying mechanisms are still unclear. MATERIALS AND METHODS: The C57BL/6 male mice were randomly divided into four groups, including control group, model group, DNLA treatment group, and simvastatin positive control group...

Gypenosides extracted from Gynostemma pentaphyllum (Thunb.) Makino have significant role in reducing serum lipid level and treating fatty liver diseases, however, without clear mechanism. As gypenosides share the similar core structures with bile acids (the endogenous ligands of nuclear receptor FXR), we hypothesize that gypenosides may improve hypercholesterolemia via FXR-mediated bile acids signaling. The present study was designed to validate the role of gypenosides in reducing levels of serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C), as well as in regulating bile acids homeostasis and related gene expression levels...

The present study was aimed to investigate the low temperature toxicity and its protection by taurine in pufferfish. The experimental basal diets supplemented with taurine at the rates of 250 (control), 550, 850, 1140, 1430, 1740 mg kg-1 were fed to fish for 8 weeks. The results showed that fish fed diet with taurine had significantly improved weight gain and specific growth rate. After the feeding trial, the fish were then exposed to low temperature stress. The results showed that low temperature stress could induce reactive oxygen species (ROS) generation, disturb the cytoplasm Ca2+ homeostasis, and lead to oxidative stress and apoptosis...

Bile acids (BAs), the most important endogenous and signaling molecules regulate the target transporters and enzymes at transcriptional level, participate in a wide variety of processes throughout the entire gastrointestinal tract to orchestrate homeostasis in vivo. BAs and their metabolism and transportation appear to follow the clear circadian rhythms, and they are recently proposed also as the potential chronobiological signals that can affect the molecular clock mechanism. Cholecystectomy are believed to affect the circadian rhythms of BAs and the relevant enterohepatic transporters and enzymes systems and their regulatory signaling pathways, for the reason that the circadian cycle of gallbladder filling and emptying play a pivotal role in controlling the flow of bile into the intestine and the enterohepatic circulation of BAs...

Bile acid homeostasis is maintained by liver synthesis, bile duct secretion, microbial metabolism and intestinal reabsorption into the blood. When drug insults result in liver damage, the variances of bile acids (BAs) are related to the physiological status of the liver. Here, we established a method to simultaneously quantify 19 BAs in rat plasma, liver, bile and different intestinal section contents (duodenum, jejunum, ileum, cecum and colon) using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) to reveal the pattern of bile acid homeostasis in the enterohepatic circulation of bile acids in physiological situations...

BACKGROUND: Various physiological and pathological stimuli can hypersensitize the sympathetic nervous system resulting in a substantial release of catecholamines (CA) and consequent alterations in excitation-contraction coupling and excitation-transcription coupling. OBSERVATIONS: It has been shown that oxidation products of CA, rather than CA themselves, are responsible for such adaptation to a new equilibrium. While chronic, sustained accumulation of CA and their toxic products are associated with the depression in cardiac contractile force and remodeling, acute excessive release of CA can result in brief oxidative bursts and serious damage leading in lethal arrhythmias...

Objective: To elucidate the effect of taurine on neurotoxicity induced by Mn by investigating activities of Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase and content of Mn and active calmodulin in manganese exposed rats. Methods: 156 male SD rats were randomly divided into 1 control group, 3 manganese exposed groups (10, 15, and 20 mg/kg respectively) , and 9 taurine intervened groups based on orthogonal design (doses of taurine intervention were 100, 150, and 200 mg/kg respectively) , with 12 rats in each group...

Glutamate-mediated excitotoxicity involving N-methyl-d-aspartate (NMDA) receptors has been recognized as a final common outcome in pathological conditions involving death of retinal ganglion cells (RGCs). Overstimulation of NMDA receptors results in influx of calcium (Ca) and sodium (Na) ions and efflux of potassium (K). NMDA receptors are blocked by magnesium (Mg). Such changes due to NMDA overstimulation are also associated with not only the altered levels of minerals but also that of trace elements and redox status...

Four premises for rooster sperm preservation were outlined previously. Understanding mitochondrial Ca cycling in terms of whole-cell Ca flux was one premise. The present work tested the hypothesis that sperm mitochondria can be damaged by intracellular as well as extracellular Ca. Sperm were washed by centrifugation through 12% (wt/vol) Sperm were washed by centrifugation through 12%(at/vol) Accudenz to procure sperm at a physiological concentration within a chemically-defined suspension. Five solutions were tested...

PURPOSE: Increased lenticular oxidative stress and altered calcium/magnesium (Ca/Mg) homeostasis underlie cataractogenesis. We developed a liposomal formulation of magnesium taurate (MgT) and studied its effects on Ca/Mg homeostasis and lenticular oxidative and nitrosative stress in galactose-fed rats. METHODS: The galactose-fed rats were topically treated with liposomal MgT (LMgT), liposomal taurine (LTau), or corresponding vehicles twice daily for 28 days with weekly anterior segment imaging...

Taurine (Tau) regulates β-cell function and glucose homeostasis under normal and diabetic conditions. Here, we assessed the effects of Tau supplementation upon glucose homeostasis and the morphophysiology of endocrine pancreas, in leptin-deficient obese (ob) mice. From weaning until 90-day-old, C57Bl/6 and ob mice received, or not, 5% Tau in drinking water (C, CT, ob and obT). Obese mice were hyperglycemic, glucose intolerant, insulin resistant, and exhibited higher hepatic glucose output. Tau supplementation did not prevent obesity, but ameliorated glucose homeostasis in obT...

Pathophysiological conditions challenge cell volume homeostasis and perturb cell volume regulatory mechanisms leading to alterations of cell metabolism, active transepithelial transport, cell migration, and death. We report that inhibition of the 5-lipoxygenase (5-LO) with AA861 or ETH 615-139, the cysteinyl leukotriene 1 receptor (CysLT₁) with the antiasthmatic drug Zafirlukast, or the volume-sensitive organic anion channel (VSOAC) with DIDS blocks the release of organic osmolytes (taurine, meAIB) and the concomitant cell volume restoration following hypoosmotic swelling of human type II-like lung epithelial cells (A549)...

Previous work has shown that taurine protected neurons against unconjugated bilirubin (UCB)-induced neurotoxicity by preventing cell apoptosis and maintaining intracellular Ca²⁺ homeostasis in primary neuron culture. This study investigates the neurotoxicity of hyperbilirubinemia and neuroprotection of taurine in a clinically relevant murine model in vivo. A hyperbilirubinemia baby mice model was established by intraperitoneal injection with UCB. After 24 h, the neural apoptotic level, transcriptional activity of caspase-3, and iCa²⁺ concentration were detected...

Diabetes mellitus is known to impair glucose metabolism. The fundamental mechanism underlying hyperglycaemia in diabetes mellitus involves decreased utilization of glucose by the brain. However, mechanisms responsible for progressive failure of glycaemic regulation in type I (IDDM) diabetes need extensive and proper understanding. Hence the present study was initiated. Type I diabetes was induced in albino rat models with alloxan monohydrate (40 mg/Kg iv). Cerebral cortex and medulla oblongata were studied 48 h after alloxanisation...

BACKGROUND: Taurine (TAU), a naturally occurring sulfur-containing amino acid, is found at high concentrations in plasma and mammalian tissues and regulates osmolarity, ion channel activity, and glucose homeostasis. Several reports have shown that physiological plasma TAU levels seem to be important for adequate beta (beta)-cell function and insulin action, since low concentrations of TAU in the plasma have been reported in the pre-diabetic and diabetic states. METHODS: Glucose tolerance and insulin sensitivity were investigated in mice supplemented with 2% (w/v) TAU in their drinking water for 30 days, as well as the insulin secretion from isolated islets stimulated by glucose or L-leucine...

The effect of taurine on calcium homeostasis of isolated cochlear spiral ganglion neurons under normal and ototoxic conditions was investigated using fluo-3 calcium imaging. Sole application of taurine (15 mM) induced an increase in intracelluar Ca(2+) concentration ([Ca(2+)](i)), which was largely inhibited either by the application of an L-type calcium-channel blocker nifedipine or a calcium-free medium. Preincubation with 1 mM gentamicin induced an inhibition of the high K(+)-evoked elevation of [Ca(2+)](i)...