venous administration of ouabain to human subjects for 9 consecutive days resulted in the establishment of a plateau of plasma concentration and urinary excretion after 4-5 days, confirming plasma and urinary half-lives in the 19-24-hour range. The mean ratio of renal clearance of ouabain to that of creatinine was 0.81 in the human subjects. The plasma half-life of ouabain determined in these s...

venous administration of ouabain to human subjects for 9 consecutive days resulted in the establishment of a plateau of plasma concentration and urinary excretion after 4-5 days, confirming plasma and urinary half-lives in the 19-24-hour range. The mean ratio of renal clearance of ouabain to that of creatinine was 0.81 in the human subjects. The plasma half-life of ouabain determined in these s...

venous administration of ouabain to human subjects for 9 consecutive days resulted in the establishment of a plateau of plasma concentration and urinary excretion after 4-5 days, confirming plasma and urinary half-lives in the 19-24-hour range. The mean ratio of renal clearance of ouabain to that of creatinine was 0.81 in the human subjects. The plasma half-life of ouabain determined in these s...

Sympathetic hyperactivity and hypertension caused by chronic treatment with ouabain or sodium-rich artificial cerebrospinal fluid (aCSF) can be prevented by central administration of an angiotensin type 1 (AT(1)) receptor blocker. In the present study, we assessed whether, in Wistar rats, chronic peripheral treatment with the AT(1) receptor blockers losartan and embusartan can exert sufficient ...

In a previous study, we demonstrated that the red blood cell Na+ concentration and Na+,K+-ATPase activity are sex-dependent and race-dependent: a higher intracellular Na+ concentration in blacks and men was associated with a lower Na+,K+-ATPase activity. To examine whether the low Na+,K+-ATPase activity is due to a decreased number of enzyme units, altered structure of the enzyme, or the presen...

1. Surgical thyroidectomy decreased specific [3H]-ouabain binding to heart ventricular microsomes by 43% and gastrocnemius muscle microsomes by 34%. Administration of triiodothyronine to euthyroid rats enhanced specific [3H]-ouabain binding to heart and skeletal muscle membrane by 60% and 33% respectively. 2. Treatment of thyroidectomized rats with triiodothyronine increased specific [3H]-ouaba...

Direct demonstration of the cellular location of sodium pumping constitutes a key problem in the solution of intestinal sodium absorption. Utilizing silicone-impregnated epoxy sections of freeze-dried, osmium-fixed tissue, ouabain-(3)H and inulin-(3)H light microscope radioautographs have been produced which show that: lateral but not brush border membranes of rabbit small intestine bind ouabai...

Ouabain, at all concentrations higher than 2 x 10(-7) mol l-1, stimulates the rate at which the Malpighian tubules of the insect, Rhodnius, transport sodium ions and fluid into the lumen. An effect on paracellular movement of sodium ions is unlikely because ouabain makes the electrical potential of the lumen more positive, which would slow diffusion of sodium into the lumen. Radioactive ouabain...

Because catecholamines and digitalis have different effects on the time course of myocardial intracellular calcium concentration, their effects on the time course of left ventricular contraction and relaxation may also be different. To study this question, dogs were instrumented to measure left ventricular pressure and determine left ventricular volume from three ultrasonic dimensions. After fu...

A s s T R A C X The binding of [SH]ouabain to the serosal side was studied in a chambered preparat ion of frog skin, free of connective tissue, while the short circuit (I~) was concurrent ly monitored. Both ouabain binding and 1~ inhibition proceeded as hyperbolic functions of time. A plot of the number of ouabain molecules bound vs. the corresponding values of Iae inhibition (percent) yielded ...