Biomaterial Database

The potassium permeability of pancreatic islet cells: mechanisms of control and influence on insulin release. 1980

J C Henquin

The K+ permeability of pancreatic islet cells was evaluated by monitoring the efflux of 42K+ or 86Rb+ and measuring the uptake of 42K+ in rat islets. Glucose rapidly and reversibly reduces 42K+ (or 86Rb+) efflux without apparent effect on the rate of 42K+ uptake. This decrease in passive K+ permeability is not secondary to insulin release as it does not require extracellular Ca, and is most marked for changes in the glucose concentration between 3 and 6 mM. This property of glucose is shared by all metabolized sugars, but by none of the nonmetabolized sugars tested. Inhibition of glucose metabolism by islet cells prevents the sugar from decreasing their K+ permeability. Reduction of the redox couple NAD(P)H/NAD(P) appears to be an important link between glucose metabolism and the K+ system in the membrane. A pharmacological decrease of the potassium permeability in islet cells (by tetraethylammonium or 9 aminoacridine) potentiates (and to some extent even mimicks) the insulin-releasing property of glucose. A pharmacological increase (by valinomycin) of this permeability inhibits glucose-stimulated insulin release. The results clearly establish the importance of the decrease in the K+ permeability of B-cell membranes for the physiological response to the stimulation by glucose.

UI	MeSH Term	Description	Entries
D007328	Insulin	A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).	Iletin,Insulin A Chain,Insulin B Chain,Insulin, Regular,Novolin,Sodium Insulin,Soluble Insulin,Chain, Insulin B,Insulin, Sodium,Insulin, Soluble,Regular Insulin
D007515	Islets of Langerhans	Irregular microscopic structures consisting of cords of endocrine cells that are scattered throughout the PANCREAS among the exocrine acini. Each islet is surrounded by connective tissue fibers and penetrated by a network of capillaries. There are four major cell types. The most abundant beta cells (50-80%) secrete INSULIN. Alpha cells (5-20%) secrete GLUCAGON. PP cells (10-35%) secrete PANCREATIC POLYPEPTIDE. Delta cells (~5%) secrete SOMATOSTATIN.	Islands of Langerhans,Islet Cells,Nesidioblasts,Pancreas, Endocrine,Pancreatic Islets,Cell, Islet,Cells, Islet,Endocrine Pancreas,Islet Cell,Islet, Pancreatic,Islets, Pancreatic,Langerhans Islands,Langerhans Islets,Nesidioblast,Pancreatic Islet
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011868	Radioisotopes	Isotopes that exhibit radioactivity and undergo radioactive decay. (From Grant & Hackh's Chemical Dictionary, 5th ed & McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Daughter Isotope,Daughter Nuclide,Radioactive Isotope,Radioactive Isotopes,Radiogenic Isotope,Radioisotope,Radionuclide,Radionuclides,Daughter Nuclides,Daugter Isotopes,Radiogenic Isotopes,Isotope, Daughter,Isotope, Radioactive,Isotope, Radiogenic,Isotopes, Daugter,Isotopes, Radioactive,Isotopes, Radiogenic,Nuclide, Daughter,Nuclides, Daughter
D002463	Cell Membrane Permeability	A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.	Permeability, Cell Membrane
D005947	Glucose	A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.	Dextrose,Anhydrous Dextrose,D-Glucose,Glucose Monohydrate,Glucose, (DL)-Isomer,Glucose, (alpha-D)-Isomer,Glucose, (beta-D)-Isomer,D Glucose,Dextrose, Anhydrous,Monohydrate, Glucose
D000585	Aminacrine	A highly fluorescent anti-infective dye used clinically as a topical antiseptic and experimentally as a mutagen, due to its interaction with DNA. It is also used as an intracellular pH indicator.	9-Aminoacridine,Acridinamine,Aminacrine Hydrochloride,Aminoacridine,Aminoacridine Hydrochloride,Aminopt,Mykocert,9 Aminoacridine,Hydrochloride, Aminacrine,Hydrochloride, Aminoacridine
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012413	Rubidium	An element that is an alkali metal. It has an atomic symbol Rb, atomic number 37, and atomic weight 85.47. It is used as a chemical reagent and in the manufacture of photoelectric cells.
D013757	Tetraethylammonium Compounds	Quaternary ammonium compounds that consist of an ammonium cation where the central nitrogen atom is bonded to four ethyl groups.	Tetramon,Tetrylammonium,Compounds, Tetraethylammonium