OBJECTIVES Fenproporex is an amphetamine-based anorectic which is rapidly converted into amphetamine in vivo. Na+, K+-ATPase is a membrane-bound enzyme necessary to maintain neuronal excitability. Considering that the effects of fenproporex on brain metabolism are poorly known and that Na+, K+-ATPase is essential for normal brain function, this study sought to evaluate the effect of this drug o...

-Adducin polymorphism in humans is associated with abnormal renal sodium handling and high blood pressure. The mechanisms by which mutations in adducin affect the renal set point for sodium excretion are not known. Decreases in Na ,K -ATPase activity attributable to endocytosis of active units in renal tubule cells by dopamine regulates sodium excretion during high-salt diet. Milan rats carryin...

The transport function of the Na pump (Na,K-ATPase) in cellular ion homeostasis involves both nucleotide binding reactions in the cytoplasm and alternating aqueous exposure of inward- and outward-facing ion binding sites. An osmotically active, nonpenetrating polymer (poly(ethyleneglycol); PEG) and a modifier of the aqueous viscosity (glycerol) were used to probe the overall and partial enzymat...

Acetylcholinesterase (AChE), Na+,K(+)-ATPase and Mg(2+)-ATPase activities were estimated in homogenised rat pituitary and hypothalamus of 4- and 22-month-old rats. AChE activity was not altered in the pituitary of aged compared to adult rats, while it was found decreased by about 40% in the hypothalamus. Na+,K(+)-ATPase activity remained stable in the hypothalamus, while it was decreased by abo...

Skeletal muscle Na(+)-K(+)-ATPase plays a central role in the clearance of K(+) from the extracellular fluid, therefore maintaining blood [K(+)]. Na(+)-K(+)-ATPase activity in peripheral tissue is impaired in insulin resistant states. We determined effects of high-fat diet (HFD) and exercise training (ET) on skeletal muscle Na(+)-K(+)-ATPase subunit expression and insulin-stimulated translocati...

The molecular basis of active ion transport in secretory glands such as the prostate is not well characterized. Rat nongastric H-K-ATPase is expressed at high levels in distal colon surface cell apical membranes and thus is referred to as "colonic." Here we show that the ATPase is expressed in rodent prostate complex in a lobe-specific manner. RT-PCR and Western blot analyses indicate that rat ...

Functional expression of the rat colonic H+-K+-ATPase was obtained by coexpressing its catalytic α-subunit and the β1-subunit of the Na+-K+-ATPase in Xenopus laevis oocytes. We observed that, in oocytes expressing the rat colonic H+-K+-ATPase but not in control oocytes (expressing β1 alone), NH4Cl induced a decrease in86Rb uptake and the initial rate of intracellular acidification induced by ex...

To clarify the suppressant action of diphenylhydantoin (DPH) on digitalis-induced arrhythmias we studied effects of DPH and digoxin, alone and in combination, on contractile force, sodium-potassium adenosinetriphosphatase (Na + -K ATPase) activity, and potassium (K) balance in dog hearts perfused with Krebs-Ringer's solution. Neither control perfusion nor DPH alone (3 X 10"M) altered Na + -K AT...

The only known cellular action of AlF4- is to stimulate the G-proteins. The aim of the present work is to demonstrate that AlF4- also inhibits 'P'-type cation-transport ATPases. NaF plus AlCl3 completely and reversibly inhibits the activity of the purified (Na+ + K+)-ATPase (Na+- and K+-activated ATPase) and of the purified plasmalemmal (Ca2+ + Mg2+)-ATPase (Ca2+-stimulated and Mg2+-dependent A...