Search results for "insulin secretion"
showing 10 items of 39 documents
Synthesis and in vitro evaluation of (S)-2-([11C]methoxy)-4-[3-methyl-1-(2-piperidine-1-yl-phenyl)-butyl-carbamoyl]-benzoic acid ([11C]methoxy-repagl…
2004
The 11 C-labeled sulfonylurea receptor 1 (SUR1) ligand (S)-2-(( 11 C)methoxy)-4-(3-methyl-1-(2-piperidine-1-yl-phenyl)- butyl-carbamoyl)-benzoic acid (( 11 C)methoxy-repaglinide) was synthesized in an overall radiochemical yield of 35% after 55 min with a radiochemical purity higher than 99%. This compound is considered for the noninvasive investigation of the SUR1 receptor status of pancreatic b-cells by positron emission tomography (PET) in the context of type 1 and type 2 diabetes. The specific activity was 40-70 GBq/lmol. In vitro testing of the nonradioactive methoxy-repaglinide was performed to characterize the affinity for binding to the human SUR1 isoform. Methoxy-repaglinide induce…
Soluble N-ethylmaleimide-sensitive-factor attachment protein and N-ethylmaleimide-insensitive factors are required for Ca2+-stimulated exocytosis of …
1996
Ca2+ stimulates exocytosis in permeabilized insulin-secreting cells. To investigate the putative cytosolic components involved in the Ca2+ response, HIT-T15 cells (a pancreatic B-cell line) were permeabilized with streptolysin-O, a procedure that allows rapid exchange of soluble components including macromolecules. We found that in this cell preparation the secretory response to Ca2+ but not to guanosine 5'-[gamma-thio]triphosphate was lost as a function of time and could be restored by rat brain cytosol in a concentration-dependent manner. Reconstitutive activity of rat brain cytosol was found in a high-molecular-mass heat-labile partially N-ethylmaleimide(NEM)-sensitive fraction. The NEM-…
Search for variants of the gene-promoter and the potential phosphotyrosine encoding sequence of the insulin receptor substrate-2 gene: evaluation of …
1999
Aims/hypothesis. The aim of this study was to screen part of the putative promoter sequence in addition to 14 potential phosphotyrosine residues of human IRS-2 for genetic variability which might cause changes in protein expression or function. Furthermore, the potential impact on insulin secretion and sensitivity of a previously identified IRS-2 variant (Gly1057Asp) was analysed Methods. The screenings were carried out by the SSCP-heteroduplex technique on DNA from Type II (non-insulin-dependent) diabetic patients. The impact of the Gly1057Asp variant was analysed in four glucose-tolerant Scandinavian study groups. Results. The results showed no nucleotide substitutions in the promoter seq…
The Impact of Amino Acids on Postprandial Glucose and Insulin Kinetics in Humans
2020
Different amino acids (AAs) may exert distinct effects on postprandial glucose and insulin concentrations. A quantitative comparison of the effects of AAs on glucose and insulin kinetics in humans is currently lacking. PubMed was queried to identify intervention studies reporting glucose and insulin concentrations after acute ingestion and/or intravenous infusion of AAs in healthy adults and those living with obesity and/or type 2 diabetes (T2DM). The systematic literature search identified 55 studies that examined the effects of l-leucine, l-isoleucine, l-alanine, l-glutamine, l-arginine, l-lysine, glycine, l-proline, l-phenylalanine, l-glutamate, branched-chain AAs (i.e., l-leucine, l-iso…
Insulin resistance and diabetes in hyperthyroidism: a possible role for oxygen and nitrogen reactive species.
2019
In addition to insulin, glycemic control involves thyroid hormones. However, an excess of thyroid hormone can disturb the blood glucose equilibrium, leading to alterations of carbohydrate metabolism and, eventually, diabetes. Indeed, experimental and clinical hyperthyroidism is often accompanied by abnormal glucose tolerance. A common characteristic of hyperthyroidism and type 2 diabetes is the altered mitochondrial efficiency caused by the enhanced production of reactive oxygen and nitrogen species. It is known that an excess of thyroid hormone leads to increased oxidant production and mitochondrial oxidative damage. It can be hypothesised that these species represent the link between hype…
Effect of simvastatin and/or pioglitazone on insulin resistance, insulin secretion, adiponectin, and proinsulin levels in nondiabetic patients at car…
2007
We investigated the effect of pioglitazone in comparison with and in combination with simvastatin on insulin resistance, plasma adiponectin, postprandial plasma glucose, insulin, and intact proinsulin levels in a nondiabetic population at cardiovascular risk. One hundred twenty-five nondiabetic patients at cardiovascular risk were randomized to pioglitazone (PIO), pioglitazone and simvastatin (PIO/SIM), or simvastatin (SIM) treatments. Blood samples were taken for the measurement of adiponectin and lipid levels. In addition, an oral glucose load with the measurements of glucose, insulin, and intact proinsulin levels was performed. Adiponectin levels increased from 14.0 ± 8.2 to 27.6 ± 14.5 …
Carnosine protects pancreatic beta cells and islets against oxidative stress damage
2018
Abstract Islet transplantation is a valid therapeutic option for type 1 diabetes treatment. However, in this procedure one of the major problems is the oxidative stress produced during pancreatic islet isolation. The aim of our study was to evaluate potential protective effects of L-carnosine and its isomer D-carnosine against oxidative stress. We evaluated the carnosine effect on cell growth, cell death, insulin production, and the main markers of oxidative stress in rat and murine stressed beta cell lines as well as in human pancreatic islets. Both isomers clearly inhibited hydrogen peroxide induced cytotoxicity, with a decrease in intracellular reactive oxygen and nitrogen species, preve…
Functional roles of the sweet taste receptor in oral and extraoral tissues
2014
International audience; Purpose of review: This review summarizes and discusses the current knowledge about the physiological roles of the sweet taste receptor in oral and extraoral tissues. Recent findings: The expression of a functional sweet taste receptor has been reported in numerous extragustatory tissues, including the gut, pancreas, bladder, brain and, more recently, bone and adipose tissues. In the gut, this receptor has been suggested to be involved in luminal glucose sensing, the release of some satiety hormones, the expression of glucose transporters, and the maintenance of glucose homeostasis. More recently, the sweet taste receptor was proposed to regulate adipogenesis and bon…
Mitochondrial reactive oxygen species are obligatory signals for glucose-induced insulin secretion.
2009
OBJECTIVE—Insulin secretion involves complex events in which the mitochondria play a pivotal role in the generation of signals that couple glucose detection to insulin secretion. Studies on the mitochondrial generation of reactive oxygen species (ROS) generally focus on chronic nutrient exposure. Here, we investigate whether transient mitochondrial ROS production linked to glucose-induced increased respiration might act as a signal for monitoring insulin secretion. RESEARCH DESIGN AND METHODS—ROS production in response to glucose was investigated in freshly isolated rat islets. ROS effects were studied using a pharmacological approach and calcium imaging. RESULTS—Transient glucose increase …
Drosophila and humans share similar mechanisms of insulin secretion
2017
Drosophila and humans share similar mechanisms of insulin secretion