Biomaterial Database

Modulation of beta-cell ouabain-sensitive 86Rb+ influx (Na+/K+ pump) by D-glucose, glibenclamide or diazoxide. 2001

A Elmi, and L A Idahl, and J Sehlin

Department of Integrative Medical Biology, Umeå University, Sweden.

The activity of the beta-cell Na+/K+ pump was studied by using ouabain-sensitive (1mM ouabain) 86Rb+ influx in beta-cell-rich islets of Umeå-ob/ob mice as an indicator of the pump function. The present results show that the stimulatory effect of glucose on ouabain-sensitive 86Rb+ influx reached its approximate maximum at 5mM glucose. Pre-treatment of the islets with 20mM glucose for 60 min strongly reduced the glucose-induced stimulation of the Na+/K+ pump. Pre-treatment (60 or 180 min) of islets at 0 mM glucose, on the other hand, did not affect the magnitude of the glucose-induced stimulation of 86Rb+ influx during the subsequent 5-min incubation. Glibenclamide stimulated the ouabain-sensitive 86Rb+ uptake in the same manner as glucose. The stimulatory effect showed its apparent maximum at 0.5 microM. Pre-treatment (60 min) of islets with 1 microM glibenclamide did not reduce the subsequent stimulation of the ouabain-sensitive 86Rb+ influx. The stimulatory effect of glibenclamide and D-glucose were not additive, suggesting that they may have the same mechanism of action. No direct effect of glibenclamide (0.01-1 microM) was observed on the Na+/K+ ATPase activity in homogenates of islets. Diazoxide (0.4mM) inhibited the Na+/K+ pump. This effect was sustained even after 60 min of pre-treatment of islets with 0.4mM diazoxide. The stimulatory effect of glibenclamide and D-glucose were abolished by diazoxide. It is concluded that nutrient as well as non-nutrient insulin secretagogues activate the Na+/K+ pump, probably as part of the membrane repolarisation process.

UI	MeSH Term	Description	Entries
D007004	Hypoglycemic Agents	Substances which lower blood glucose levels.	Antidiabetic,Antidiabetic Agent,Antidiabetic Drug,Antidiabetics,Antihyperglycemic,Antihyperglycemic Agent,Hypoglycemic,Hypoglycemic Agent,Hypoglycemic Drug,Antidiabetic Agents,Antidiabetic Drugs,Antihyperglycemic Agents,Antihyperglycemics,Hypoglycemic Drugs,Hypoglycemic Effect,Hypoglycemic Effects,Hypoglycemics,Agent, Antidiabetic,Agent, Antihyperglycemic,Agent, Hypoglycemic,Agents, Antidiabetic,Agents, Antihyperglycemic,Agents, Hypoglycemic,Drug, Antidiabetic,Drug, Hypoglycemic,Drugs, Antidiabetic,Drugs, Hypoglycemic,Effect, Hypoglycemic,Effects, Hypoglycemic
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
D008820	Mice, Obese	Mutant mice exhibiting a marked obesity coupled with overeating, hyperglycemia, hyperinsulinemia, marked insulin resistance, and infertility when in a homozygous state. They may be inbred or hybrid.	Hyperglycemic Mice,Obese Mice,Mouse, Hyperglycemic,Mouse, Obese,Hyperglycemic Mouse,Mice, Hyperglycemic,Obese Mouse
D010042	Ouabain	A cardioactive glycoside consisting of rhamnose and ouabagenin, obtained from the seeds of Strophanthus gratus and other plants of the Apocynaceae; used like DIGITALIS. It is commonly used in cell biological studies as an inhibitor of the NA(+)-K(+)-EXCHANGING ATPASE.	Acocantherin,G-Strophanthin,Acolongifloroside K,G Strophanthin
D003981	Diazoxide	A benzothiadiazine derivative that is a peripheral vasodilator used for hypertensive emergencies. It lacks diuretic effect, apparently because it lacks a sulfonamide group.	Hyperstat,Proglycem
D004791	Enzyme Inhibitors	Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.	Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D005260	Female		Females
D005905	Glyburide	An antidiabetic sulfonylurea derivative with actions like those of chlorpropamide	Glibenclamide,Daonil,Diabeta,Euglucon 5,Euglucon N,Glybenclamide,HB-419,HB-420,Maninil,Micronase,Neogluconin,HB 419,HB 420,HB419,HB420
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
D000254	Sodium-Potassium-Exchanging ATPase	An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.	ATPase, Sodium, Potassium,Adenosinetriphosphatase, Sodium, Potassium,Na(+)-K(+)-Exchanging ATPase,Na(+)-K(+)-Transporting ATPase,Potassium Pump,Sodium Pump,Sodium, Potassium ATPase,Sodium, Potassium Adenosinetriphosphatase,Sodium-Potassium Pump,Adenosine Triphosphatase, Sodium, Potassium,Na(+) K(+)-Transporting ATPase,Sodium, Potassium Adenosine Triphosphatase,ATPase Sodium, Potassium,ATPase, Sodium-Potassium-Exchanging,Adenosinetriphosphatase Sodium, Potassium,Pump, Potassium,Pump, Sodium,Pump, Sodium-Potassium,Sodium Potassium Exchanging ATPase,Sodium Potassium Pump