In an earlier study, we proposed that thyroid hormone stimulation of energy utilization by the Na(+) pump mediates the calorigenic response. In this study, the effects of triiodothyronine (T(3)) on total oxygen consumption (Q(OO2)), the ouabain-sensitive oxygen consumption [Q(OO2)(t)], and NaK-ATPase in liver, kidney, and cerebrum were measured. In liver, approximately 90% of the increase in Q(...

JAMPQL, LEE M., AND FRANKLIN H. EPSTEIN. Sodiumpotassiumactivated adenosine triphosphatase and osmotic regulation by fishes. Am. J. Physiol. 218(2) : 607-611. 1970.-The specific activity of sodiumpotassium-activated adenosine triphosphatase is high in the gills of sa1twater teleosts, and low in the gills of elasmobranchs and freshwater teleosts. The activity of NaK-ATPase in gill filaments and ...

The effects of thyroid hormone on guinea pig myocardial NaK-ATPase activity, transmembrane monovalent cation active transport, and cardiac glycoside binding were were examined. NaK-ATPase activities of left atrial and left ventricular homogenates of control and triiodothyronine (T3)-treated animals were determined, and compared to activities of skeletal muscle and liver. T3 administration was a...

PURPOSE To investigate the mechanisms involved in the damage caused by UV-A irradiation at 365 nm on the eye lens. METHODS Bovine lenses obtained from animals 1 to 5 years of age were placed in specially designed organ culture chambers for preincubation. Twenty-four hours later, the lenses were irradiated by 33 J/cm2 UV-A at 365 nm. During irradiation, the lenses were oriented in the culture ...

Topical administration of 0.5% vanadate lowers intraocular pressure in monkey and rabbit eyes. This appears to be a consequence of a reduction in the rate of aqueous humor secretion, probably resulting from the inhibition of ciliary epithelium membrane. NaK ATPase. The ubiquitous vanadate and its interactions with catecholamines and ascorbate may play a role in regulating the sodium pump of the...

Previous studies have suggested that an alteration in the expression of the NaK-ATPase of muscle may be an important determinant ofenhanced insulin sensitivity in chronic renal failure. Therefore, in the present studies we have examined the effect of uremia on the NaK-ATPase a isoforms in skeletal muscle, at the level of mRNA expression and enzymatic activity. The activity of the sodium pump, a...

Disturbances of Na,K-ATPase activity are implicated in the pathophysiology of cerebral ischemia. Previous experiments have shown that EGb 761 protects NaK-ATPase activity against one hour of cerebral ischemia. In the brain however, the 3 isoenzymes responsible for Na,K-ATPase activity may be differentially affected by various times of ischemia. In the present study, we investigated the effect o...

FXYD proteins, small single-transmembrane proteins, have been proposed to be auxiliary regulatory subunits of Na(+)-K(+)-ATPase and have recently been implied in ion osmoregulation of teleost fish. In freshwater (FW) fish, numerous ions are actively taken up through mitochondrion-rich cells (MRCs) of the gill and skin epithelia, using the Na(+) electrochemical gradient generated by Na(+)-K(+)-A...

The (sodium -Ipotassium)-activated adenosine triphosphatase (NaK ATPase) in Lubrol extracts of NaI-treated bovine brain microsomes has been purified 30 to 50 times over that in the microsomes by salt and isoelectric precipitation, zonal centrifugation, and a new ammonium sulfate fractionation procedure. The final step in the purification procedure renders the NaK ATPase insoluble. The partially...

PURPOSE Recent evidence suggests that taurine and myoinositol may serve as organic osmolytes in a number of cells, including lens and retinal pigment epithelia, but the mechanism for their increased accumulation in response to hypertonic stress is not known. To assess whether NaK ATPase contributed to the elevated levels of taurine and myoinositol in cells exposed to hypertonic media, we measur...