The effects of ouabain or ouabain and furosemide on renal function and renin secretion were studied in conscious isovolemic sheep. The sheep received a continuous renal arterial infusion of papaverine, 7 mg/min, throughout the experiment. Ouabain alone (7 X 10(-7) M in the renal plasma) produced significant decreases in glomerular filtration rate (GFR) and renal plasma flow (RPF) but not in ren...

Endogenous cardiotonic glycosides bind to the inhibitory binding site of the plasma membrane sodium pump (Na(+)/K(+)-ATPase). Plasma levels of endogenous cardiotonic glycosides increase in several disease states, such as essential hypertension and uremia. Low concentrations of ouabain, which do not inhibit Na(+)/K(+)-ATPase, induce cell proliferation. The mechanisms of ouabain-mediated response...

Conservation of the binding site on mammalian Na+,K+-ATPase for cardiac glycosides and the importance of the Na+ pump in mammalian cellular physiology has stimulated the search for a mammalian analog of these plant compounds. One candidate, isolated from brain and blood, appears to be ouabain itself or a closely related isomer, the ouabain-like compound. Little is known about the circulating fo...

An ouabain-like factor has been implicated repeatedly in salt-sensitive hypertension as a natriuretic agent. However, the response of plasma ouabain-like factor to acute and chronic variation of body sodium is unclear. We studied 138 patients with essential hypertension who underwent an acute volume expansion/contraction maneuver (2 days) and 20 patients who entered a blind randomized crossover...

Exposure of intact cells to selective inhibitors of Na(+)/K(+)-ATPase such as ouabain activates several growth-related cell signaling pathways. It has been suggested that the initial event of these pathways is the binding of ouabain to a preexisting complex of Src with Na(+)/K(+)-ATPase of the plasma membrane. The aim of this work was to evaluate the role of Src in the ouabain-induced activatio...

Ouabain is a steroid capable of binding to and inhibiting Na(+),-K(+)-ATPase. Studies have demonstrated some actions of ouabain on immune cells, which indicated both pro- and anti-inflammatory properties of this molecule. Nevertheless, its effects on human monocytes are still poorly understood. Thus, the present work investigated effects of ouabain in the activation and function of human adhere...

The mechanism of the previously reported hypoglycemic effect of ouabain was studied in dogs. Ouabain (1.0 /xg/kg/min infused intravenously for 60 minutes) combined with insulin or propranolol caused a greater and more prolonged decrease in blood glucose than either of the drugs administered separately. In intact dogs, ouabain changed significantly portohepatic venous differences in plasma gluco...

Adenosine 3',5'-cyclic monophosphate (cAMP) participates in the regulation of numerous cellular functions, including the Na(+)-K(+)-ATPase (sodium pump). Ouabain, used in the treatment of several heart diseases, is known to increase cAMP levels but its effects on the atrium are not understood. The aim of the present study was to examine the effect of ouabain on the regulation of atrial cAMP pro...

Nontoxic concentrations of ouabain, causing partial inhibition of the cardiac myocyte Na(+)/K(+)-ATPase, induce hypertrophy and several growth-related genes through signal pathways that include the activation of Ras and p42/44 mitogen-activated protein kinase (MAPK). The aim of this work was to examine the ouabain-induced events upstream of the Ras/MAPK cascade. Treatment of myocytes with genis...

In dogs anesthetized with pentobarbital, ventricular arrhythmias induced by ouabain were consistently reverted to sinus rhythm by acute lowering of the serum calcium. In ouabain-intoxicated clogs, the depressed and shortened S-T segment was elevated and lengthened by induced hypocalcemia. Potassium administered concomitantly with ouabain exerted a protective effect against ouabain intoxication....