Animals ; Biological Transport, Active/physiology* ; Centrioles/metabolism* ; Cilia/metabolism* ; Mice ; Mice, Mutant Strains ; N-Acetylglucosaminyltransferases/metabolism*

Aluminum (Al) is the most abundant metal element in the earth's crust. On acid soils, at pH 5.5 or lower, part of insoluble Al-containing minerals become solubilized into soil solution, with resultant highly toxic effects on plant growth and development. Nevertheless, some plants have developed Al-tolerance mechanisms that enable them to counteract this Al toxicity. One such well-documented mechanism is the Al-induced secretion of organic acid anions, including citrate, malate, and oxalate, from plant roots. Once secreted, these anions chelate external Al ions, thus protecting the secreting plant from Al toxicity. Genes encoding the citrate and malate transporters responsible for secretion have been identified and characterized, and accumulating evidence indicates that regulation of the expression of these transporter genes is critical for plant Al tolerance. In this review, we outline the recent history of research into plant Al-tolerance mechanisms, with special emphasis on the physiology of Al-induced secretion of organic acid anions from plant roots. In particular, we summarize the identification of genes encoding organic acid transporters and review current understanding of genes regulating organic acid secretion. We also discuss the possible signaling pathways regulating the expression of organic acid transporter genes.
Aluminum ; toxicity ; Anions ; Biological Transport ; drug effects ; Citric Acid ; metabolism ; Malates ; metabolism ; Oxalic Acid ; metabolism ; Plant Roots ; drug effects ; metabolism ; Signal Transduction ; physiology

Facilitative glucose transporters (GLUT) are proteins that mediate glucose transmembrane transport in the form of facilitated diffusion, which play an important role in regulating cell energy metabolism. There are many breakthroughs in researches of facilitative GLUT in recent years. It has been known that there are 14 subtypes of facilitative GLUT with obvious tissue specificity in distribution and physiological function. In the present review, the tissue and cellular distribution, subcellular localization, expression regulation, physiological function and the relationship to diseases of facilitative GLUT subtypes were summarized, in order to further understand their physiological and pathophysiological significances.
Biological Transport ; Disease ; Energy Metabolism ; Glucose ; Glucose Transport Proteins, Facilitative ; physiology ; Humans

The function of kidney is maintaining water balance of our body through regulation of urine concentration and dilution. The aquaporins are molecular basis of renal urine production and water transport, and their expression and membrane translocation are regulated delicately. Nuclear receptors are a superfamily of ligand-activated transcription factors consisting of 48 members in human. They widely participate in a variety of physiological and pathophysiological regulation including growth and development, glucose and lipid metabolism, inflammation, immunology by regulating target gene transcription and expression. Increasing evidence demonstrates that these receptors are involved in the regulation of aquaporins expression and membrane translocation in kidney, thereby playing a major role in water homeostasis. Here we review the role of nuclear receptors in regulating renal water transport.
Aquaporins ; physiology ; Biological Transport ; Homeostasis ; Humans ; Kidney ; physiology ; Receptors, Cytoplasmic and Nuclear ; physiology ; Water

OBJECTIVE: To explore the interaction between arginine functionalized hydroxyapatite (HAP/Arg) nanoparticles and endothelial cells, and to investigate mechanisms for endocytosis kinetics and endocytosis.
 METHODS: Human umbilical vein endothelial cells (HUVECs) were selected as the research model.Cellular uptake of HAP/Arg nanoparticles were observed by laser scanning confocal microscopy.Average fluorescence intensity of cells after ingestion with different concentrations of HAP/Arg nanoparticles were determined by flow cytometer and atomic force microscopy.
 RESULTS: The HAP/Arg nanoparticles with doped terbium existed in cytoplasm, and most of them distributed around the nucleus area after cellular uptake by HUVECs. Cellular uptake process of HAP/Arg nanoparticles in HUVECs was in a time and concentration dependent manner. 4 h and 50 mg/L was the best condition for uptake. HAP/Arg nanoparticles were easier to be up-taken into the cells than HAP nanoparticles without arginine functionalized.
 CONCLUSION HAP/Arg nanoparticles are internalized by HUVECs cells through an active transport and energy-dependent endocytosis process, and it is up-taken by cells mainly through caveolin-mediated endocytosis, but the clathrin-dependent endocytic pathway is also involved..
Arginine ; pharmacology ; Biological Transport, Active ; physiology ; Caveolins ; physiology ; Cells, Cultured ; Clathrin ; physiology ; Durapatite ; pharmacokinetics ; Endocytosis ; physiology ; Human Umbilical Vein Endothelial Cells ; cytology ; Humans ; Nanoparticles ; metabolism

To discuss the protective effect of aralosides (AS) on I/R-induced rat myocardial injury. The adult rat ventricular myocyte ischemia model was established through perfusion with sodium lactate perfusate and reperfusion with Ca(2+) -containing Tyrode's solution simulation. The cell contraction and ion concentration synchronization determination system was applied to detect the effect of AS on single I/R cell contraction and Ca2+ transients. According to the findings, AS could increase resting sarcomere length, contraction amplitude, ± dL/dt(max), calcium transient amplitude and speed of post-reperfusion myocardial cells (P < 0.05, P < 0.01), and decrease in time for achieving 90.0% of maximum relaxation, time for achieving peak value, resting calcium ratio, contraction period [Ca2+] i, time for achieving 50.0% of maximum relaxation and attenuation rate of intracellular calcium transient (P < 0.05, P < 0.01). Therefore, it is suggested that AS improved the post-reperfusion cell contraction and injury of calcium homeostasis.
Animals ; Aralia ; chemistry ; Biological Transport ; drug effects ; Calcium ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Humans ; Male ; Muscle Contraction ; drug effects ; Myocardial Ischemia ; drug therapy ; metabolism ; physiopathology ; surgery ; Myocardial Reperfusion ; Myocytes, Cardiac ; drug effects ; physiology ; Rats ; Rats, Sprague-Dawley ; Saponins ; administration & dosage

With the wide application of Chinese herbal medicine, herb-drug interaction (HDI) has become increasingly prominent. Metabolic enzymes and transporters are the main targets of HDI, because the changes in expression and function of enzymes and transporters can influence the disposition of drugs. Metabolic enzymes are responsible for the metabolic clearance of drugs, including cytochrome P450 (CYP), UDP-glucuronyl transferase (UGT) and sulfotransferases (SULT); transporters widely expressed in the intestine, kidney, liver and brain are involved in the oral absorption, distribution and excretion of drugs. Pueraria, ginkgo, ginseng, St. John's wort and other Chinese herbal medicine often induce a HDI because those herbal medicines combined with chemical medicine are widely used in clinic. The components of herb medicines mentioned above are prone to interact with enzymes and transporters, which often induce a HDI. This paper reviews the advances in the study of enzymes and transporters-mediated pharmacokinetic mechanism of HDI.
Biological Products ; Biological Transport ; Cytochrome P-450 Enzyme System ; physiology ; Drugs, Chinese Herbal ; Ginkgo biloba ; Glucuronosyltransferase ; physiology ; Herb-Drug Interactions ; Humans ; Membrane Transport Proteins ; physiology ; Oxidation-Reduction ; Panax ; Plants, Medicinal ; Pueraria

Organic anion transporting polypeptides (OATP), a member of solute carrier (SLC) superfamily, is considered as an important transmembrane uptake transporters. OATP is involved in the transport of a variety of endo- and xenobiotics (bile acids, bilirubin, prostaglandin, thyroid hormones, steroid hormone conjugates), drugs and toxins in a Na+ and ATP independent manner. Multiple factors (eg. hormones, proinflammatory cytokines, drugs) can affect the distribution, expression and activity of OATPs, leading to an altered accumulation of OATP substrates and related food-drug and drug-drug interactions. Changes in the distribution and expression of OATPs in malignant tissues may be related to the pathological process of cancer, while the modulation epigenetic mechanism also contributes to its distribution patterns. This review describes the factors that can affect the expression or function of OATPs, which may provide a valuable reference for drug development and the clarification of pathogenesis.
Biological Transport ; Humans ; Neoplasms ; Organic Anion Transporters ; physiology ; Xenobiotics

To study the transport mechanisms of drugs for transplacental treatment of fetal tachyarrhythmia, MDCKII-BCRP and MDCKII cell models was used. MDCKII-BCRP and MDCKII cell monolayer model was used to investigate the bi-direction transport of sotalol, propranolol, propafenone, procainamide and flecainide. Drug concentrations were measured by HPLC-UV or chemiluminescence. The apparent permeability coefficient (P(app)), efflux rate (R(E)) and net efflux rate (R(net)) were calculated. Drugs with R(net) greater than 1.5 were further investigated using cellular accumulation experiments with or without a BCRP inhibitor. The R(net) of sotalol, propranolol, propafenone and procainamide were less than 1.5, while R(net) of flecainide with concentrations of 20 and 5 μmol x L(-1) were 1.6 and 1.9, respectively. The results showed that the transport of flecainide on MDCKII-BCRP cell monolayer could be mediated by BCRP; and the affinity increased when the concentration of flecainide decreased. Cellular accumulation experiments further suggested that accumulation of flecainide in MDCKII-BCRP cells was significantly lower than that in MDCKII cells in a concentration-dependent manner. BCRP inhibitor quercetin (50 μmol x L(-1)) significantly increased the accumulation of flecainide in MDCKII-BCRP cells (P < 0.05). Our preliminary data showed that flecainide but not sotalol, propranolol, propafenone or procainamide can be a substrate of BCRP. Thus the effect of flecainide may be affected by the BCRP in the maternal placental trophoblast membrane layer when treating fetal tachyarrhythmia.
Animals ; Biological Transport ; Cell Membrane Permeability ; Dogs ; Female ; Flecainide ; metabolism ; Madin Darby Canine Kidney Cells ; metabolism ; Placenta ; physiology ; Pregnancy ; Tachycardia ; drug therapy

OBJECTIVETo evaluate whether ursolic acid can inhibit breast cancer resistance protein (BCRP)-mediated transport of rosuvastatin in vivo and in vitro.

METHODSFirstly, we explored the pharmacokinetics of 5-fluorouracil (5-FU, a substrate of BCRP) in rats in the presence or absence of ursolic acid. Secondly, we studied the pharmacokinetics of rosuvastatin in rats in the presence or absence of ursolic acid or Ko143 (inhibitor of BCRP). Finially, the concentration-dependent transport of rosuvastatin and the inhibitory effects of ursolic acid and Ko143 were examined in Madin-Darby Canine Kidney (MDCK) 2-BCRP421CC (wild type) cells and MDCK2-BCRP421AA (mutant type) cells.

RESULTSAs a result, significant changes in pharmacokinetics parameters of 5-FU were observed in rats following pretreatment with ursolic acid. Both ursolic acid and Ko143 could significantly affect the pharmacokinetics of rosuvastatin. The rosuvastatin transport in the BCRP overexpressing system was increased in a concentration-dependent manner. However, there was no statistical difference in BCRP-mediated transport of rosuvastatin betweent the wild type cells and mutant cells. The same as Ko143, ursolic acid inhibited BCRP-mediated transport of rosuvastatin in vitro.

CONCLUSIONUrsolic acid appears to be a potent modulator of BCRP that affects the pharmacokinetic of rosuvastatin in vivo and inhibits the transport of rosuvastatin in vitro.

ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; physiology ; Adenosine ; analogs & derivatives ; pharmacology ; Animals ; Biological Transport ; drug effects ; Diketopiperazines ; Heterocyclic Compounds, 4 or More Rings ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; pharmacokinetics ; Rats ; Rats, Sprague-Dawley ; Rosuvastatin Calcium ; pharmacokinetics ; Triterpenes ; pharmacology