The effective concentration of a drug in the blood, i.e. the concentration of a free drug in the blood, is influenced by the strength of drug binding onto plasma proteins. Besides its efficacy, these interactions subsequently influence the liberation, absorption, distribution, metabolism, excretion, and toxicological properties of the drug. It is important to not only determine the binding strength and stoichiometry, but also the binding site of a drug on the plasma protein molecule, because the co-administration of drugs with the same binding site can affect the above-mentioned concentration and as a result the pharmacological behavior of the drugs and lead to side effects caused by the change in free drug concentration, its toxicity. In this study, the binding characteristics of six drugs with human serum albumin, the most abundant protein in human plasma, were determined by capillary electrophoresis-frontal analysis, and the obtained values of binding parameters were compared with the literature data. The effect of several drugs and site markers on the binding of l-tryptophan and lidocaine to human serum albumin was investigated in subsequent displacement studies which thus demonstrated the usability of capillary electrophoresis as an automated high-throughput screening method for drug-protein binding studies.
- MeSH
- chlorpropamid analýza farmakologie MeSH
- diklofenak analýza farmakologie MeSH
- elektroforéza kapilární MeSH
- fenylbutazon analýza farmakologie MeSH
- flurbiprofen analýza farmakologie MeSH
- ibuprofen analýza farmakologie MeSH
- lidé MeSH
- lidokain antagonisté a inhibitory chemie MeSH
- lidský sérový albumin chemie MeSH
- tolbutamid analýza farmakologie MeSH
- tryptofan antagonisté a inhibitory chemie MeSH
- vazebná místa účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Despite the urgent need for assays to visualize insulin secretion there is to date no reliable method available for measuring insulin release from single cells. To address this need, we developed a genetically encoded reporter termed RINS1 based on proinsulin superfolder GFP (sfGFP) and mCherry fusions for monitoring insulin secretion. RINS1 expression in MIN6 β cells resulted in proper processing yielding single-labeled insulin species. Unexpectedly, glucose or drug stimulation of insulin secretion in β cells led to the preferential release of the insulin-sfGFP construct, while the mCherry-fused C-peptide remained trapped in exocytic granules. This physical separation was used to monitor glucose-stimulated insulin secretion ratiometrically by total internal reflection fluorescence microscopy in single MIN6 and primary mouse β cells. Further, RINS1 enabled parallel monitoring of pulsatile insulin release in tolbutamide-treated β cells, demonstrating the potential of RINS1 for investigations of antidiabetic drug candidates at the single-cell level.
- MeSH
- beta-buňky cytologie účinky léků metabolismus sekrece MeSH
- biosenzitivní techniky MeSH
- buněčné linie MeSH
- fluorescenční mikroskopie MeSH
- glukosa farmakologie MeSH
- hypoglykemika farmakologie MeSH
- inzulin metabolismus sekrece MeSH
- luminescentní proteiny genetika metabolismus MeSH
- myši MeSH
- rekombinantní fúzní proteiny metabolismus sekrece MeSH
- reportérové geny MeSH
- tolbutamid farmakologie MeSH
- vápník metabolismus MeSH
- zelené fluorescenční proteiny genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVES: A "cocktail" of several substrates is frequently used to assess metabolic activity of multiple cytochrome P450 enzymes in one session. Some interactions among substrates can appear and may influence the rate of biotransformation of other ones. Our current work was aimed on the influence of tolbutamide on cytochrome P450-mediated metabolism of phenacetin and vice versa. DESIGN: In the presented work, the biotransformation rates of phenacetin and tolbutamide (markers of rat CYP1A2 and CYP2C6/11 metabolic activities, respectively) administered either separately or both simultaneously were compared. The model of isolated perfused rat liver was used. RESULTS: Phenacetin had no significant effect on tolbutamide hydroxylation. Tolbutamide addition to the perfusion medium significantly increased the rate of O-deethylation of phenacetin. CONCLUSION: Some differences in the rate of P450-mediated metabolism can be observed when comparing assessment using combination of two model substrates with the common way (single marker administration). Due to these differences, results obtained by the mentioned methodologies might not be fully comparable.
- MeSH
- biotransformace MeSH
- časové faktory MeSH
- fenacetin metabolismus farmakologie MeSH
- játra účinky léků metabolismus MeSH
- krysa rodu rattus MeSH
- potkani Wistar MeSH
- systém (enzymů) cytochromů P-450 chemie metabolismus MeSH
- tolbutamid metabolismus farmakologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- chlorpropamid farmakologie terapeutické užití MeSH
- diabetes mellitus 2. typu * farmakoterapie MeSH
- gliklazid farmakologie terapeutické užití MeSH
- glipizid farmakologie terapeutické užití MeSH
- hypoglykemika * farmakologie terapeutické užití MeSH
- kardiovaskulární nemoci MeSH
- klinická studie jako téma MeSH
- lékové interakce MeSH
- lidé MeSH
- metabolický syndrom farmakoterapie MeSH
- nežádoucí účinky léčiv MeSH
- sulfonylmočovinové sloučeniny * farmakokinetika farmakologie kontraindikace terapeutické užití MeSH
- tolbutamid farmakologie terapeutické užití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
