Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in the cation balance cause hydration and initiate the process of lens opacification. Such alterations were studied in human cataractous lenses and during the development of alloxan-induced diabetic cataract in rats by biochemical and histochemical techniques. The development of alloxan-induced cataract in rats was examined in vivo which showed cortical opacities beginning after 32 days. These opacities did progress to maturity after 64 days and finally the lenses were completely opacified after 96 days of alloxan treatment. The histochemical localization of sodium-potassium-activated adenosine triphosphatase using three different methods provided information on the possible role of this enzyme in normal and cataractous lenses. In human cataractous lenses, sodium-potassium adenosine triphosphatase activity was found to be considerably decreased, whereas no activity of this enzyme was localized in human diabetic cataractous lenses. An animal model provided evidence that an apparent decrease of sodium-potassium adenosine triphosphatase may be involved in the initiation of alloxan-induced diabetic cataract in rats.
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PMID:Studies on cataractogenesis in humans and in rats with alloxan-induced diabetes. I. Cation transport and sodium-potassium-dependent ATPase. 298 22

The in vitro effect of porcine insulin on Na+ + K+, Ca2+- and Mg2+-ATPases of the rat erythrocyte membrane of normal and alloxan-induced diabetic rats was investigated. Na+ + K+- and Ca2+-stimulated enzyme activities were significantly decreased in diabetic rats in comparison to normal animals. The specific activities of both these ATPases in the latter group were markedly reduced on pre-incubating the ghosts with insulin. Similar treatment of the erythrocyte membranes of diabetic animals, however, resulted in a significant increase of these activities. These qualitatively different effects of the hormone in the two groups increased progressively with hormone concentration and duration of pre-incubation. Mg2+-stimulated ATPase activity was not significantly affected in diabetes or by insulin.
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PMID:In vitro insulin action on different ATPases of erythrocyte membranes in normal and diabetic rats. 300 Jan 16

The retinal pigmented epithelium (RPE), which influences the composition of the retinal extracellular fluid, is significantly affected in diabetes. Changes in RPE morphology, permeability, and electrophysiology in experimentally diabetic animals have been described. To facilitate the study of diabetes-related changes in RPE metabolism, we applied the techniques of quantitative histochemistry to pure samples of RPE and individual retinal layers from eyes of normal and alloxan-diabetic rabbits. Glucose within the RPE approximated serum levels in both normal and diabetic animals. Other changes in diabetics included increased sorbitol, decreased myo-inositol, elevated total Na, and loss of measurable Na+-K+-ATPase activity within the RPE. The altered ion metabolism was associated with a progressive decrease in the amplitude of the RPE-generated c-wave of the electroretinogram. The deterioration of the c-wave was arrested by treatment of the diabetic animals with either myo-inositol supplementation or with sorbinil, an inhibitor of aldose reduction. Diabetic alterations in the RPE might impair the ability of the tissue to maintain normal transport functions. The subsequently altered composition of the extracellular environment of the retina may play an important role in the pathogenesis of diabetic retinopathy.
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PMID:Experimental diabetes mellitus impairs the function of the retinal pigmented epithelium. 300 25

This study was undertaken to characterize catecholamine-induced myocardial necrosis in 10-week alloxan-diabetic rabbits. Myocardial injury was induced by administering graded doses of isoproterenol (ISO) for 15 days. Injection of ISO to control and diabetic rabbits resulted in atrial tachycardias and ventricular fibrillation. The severity of the arrhythmias and the overall mortality was the same in both groups of animals. Analyses of serum biochemical parameters revealed significant increases in blood glucose, free fatty acids and total cholesterol in the ISO-treated diabetic animals relative to ISO-treated controls. ISO-treatment of both control and diabetic animals showed similar increases in heart weight, left ventricular weight and myocardial total water content. Analyses of various subcellular organelle marker enzyme activities indicated a significant decrease in the K+, Ca2+-stimulated sarcoplasmic reticulum, mitochondrial (azide-sensitive) and sarcolemmal Na+, K+-stimulated ATPase activities, decreases in ATP and glycogen and increases in myocardial sodium content in both the ISO-treated control and diabetic animal hearts. In addition, significant accumulation of Ca2+ and hydroxyproline were evident in the ISO-treated diabetic animal hearts.
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PMID:Isoproterenol-induced myocardial alterations in alloxan-diabetic rabbits. 302 4

The biochemical and functional changes associated with ligation (40 min) of the left circumflex coronary artery and subsequent reperfusion (60 min) in the rabbit made diabetic with alloxan were studied and compared with those of control animals. Measurement of haemodynamic parameters revealed that both left ventricular pressure and mean arterial pressure were significantly (P less than 0.05) decreased after ligation and reperfusion in the diabetic animals compared with controls. Analysis of subcellular organelle enzyme markers from the ischaemic tissue revealed that sarcolemmal Na+,K+-ATPase, mitochondrial ATPase and sarcoplasmic reticulum ATPase activities were decreased after ligation to the same extent in the diabetic and control animals. However, upon reperfusion, the recovery of mitochondrial ATPase activity was significantly (P less than 0.05) less in the diabetic animals than in the controls. Ion measurements revealed a significant (P less than 0.05) depletion of Mg in diabetic hearts before ligation, and this was augmented during reperfusion. In contrast, a significantly (P less than 0.05) higher calcium accumulation was observed upon reperfusion in the hearts of diabetic animals. Similarly, both tissue ATP levels and the ability of the mitochondria to generate ATP were depressed to a greater degree in the diabetic animals. Our results indicate, therefore, a greater susceptibility of the diabetic myocardium to ischaemic/reperfusion injury which in the clinical situation would exacerbate the problems associated with atherosclerosis and possibly contribute to the high mortality from cardiovascular complications in diabetic patients.
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PMID:Coronary artery ligation and reperfusion in rabbits made diabetic with alloxan. 381 32

The effect of alloxan diabetes on the activities of Na+,K+-ATPase and Mg2+-ATPase was studied in three regions of rat brain at various time intervals after the onset of diabetes. It was observed that Na+,K+-ATPase activity increased at early time intervals after diabetes, followed by a recovery to near control levels in all three regions of the brain. There was an overall increase in Mg2+-ATPase activity in all the regions. A reversal of the effect was observed with insulin administration to the diabetic rats.
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PMID:Na+,K+-ATPase and Mg2+-ATPase activities in different regions of rat brain during alloxan diabetes. 612 23

An ouabain-insensitive, Mg++-dependent, Na+-stimulated ATPase activity which is inhibited by furosemide was found in mucosal homogenate of rat small intestine. The subcellular localization of this ATPase activity was studied by means of isolated purified brush borders and basolateral plasma membranes. The results suggest a nearly identical distribution of Na+-activated and (Na+K+)-activated ATPase within the epithelial cells. Under conditions of alloxan and streptozotocin diabetes an increase of both ATPase activities can be found only in the basolateral plasma membranes. These observations agree well with the convective model of intestinal absorption.
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PMID:[Detection of a Na+-activated, furosemide-inhibited ATPase activity in rat intestinal mucosa]. 622 94

This study was conducted to investigate myocardial excitation-contraction coupling in the fetus of the diabetic rabbit (FDM). On day 14 of gestation, diabetes was induced in pregnant rabbits by alloxan injection. On day 28 of gestation, mechanical function of the fetal myocardium was determined in the isolated arterially perfused heart preparation. At 1.5 mM [Ca2+]o (control), the force of myocardial contraction in FDM was not significantly different from that in the control fetus. At higher [Ca2+]o, developed tension and maximal rate of tension development [+dT/dt (max)] in FDM were significantly greater than in the control fetus. High [Ca2+]o caused significant increases in resting tension and half-relaxation time (toxic effects) in the control fetus, but not in FDM. Perfusion with lanthanum (known to displace sarcolemma-bound Ca2+ and block sarcolemmal Na-Ca exchange) decreased developed tension and +dT/dt (max) and increased resting tension and these effects in FDM were significantly less than in the control fetus. Perfusion with manganese (known to displace Ca2+ from intracellular sites) also decreased developed tension and +dT/dt (max) and increased resting tension, and these effects were similar in the two groups. The myofibrillar ATPase activities at various calcium concentrations were not different between the two groups. The rates of Ca2+ uptake by mitochondria and sarcoplasmic reticulum were similar in the two groups. These data suggest that in FDM the inotropic effect of Ca2+ is greater and the toxic effect of Ca2+ is less than in the control fetus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Myocardial excitation-contraction coupling in the fetus of alloxan-diabetic rabbit. 624 Jun 30

Insulin is apparently not required for VMH glucose oxidation in vitro. Ouabain, an inhibitor of the Na-K pump ATPase, does not prevent VMH glucose oxidation in vitro. These data suggest (a) the VMH does not exhibit a cotransport phenomenon of glucose with the Na-K pump mechanism, and (b) glucose oxidation in the VMH is not insulin dependent. Alloxan-diabetes was induced to increase tissue insulin sensitivity. A comparison of glucose oxidation rates in alloxan-diabetic VMH tissue and normal VMH tissue, supplemented only with saline, indicated a highly significant (p < 0.001) depression of glucose oxidation in the alloxan-treated tissue. Cell membranes in the VMH are perhaps altered by alloxan.
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PMID:Glucose oxidation in the ventromedial hypothalamus is not affected by insulin or ouabain but depressed by alloxan treatment. 625 92

Adenine nucleotide translocase (EC 3.6.1.3.), pyruvate dehydrogenase (active and total forms, EC 1.2.4.1) and the long chain acyl CoA content were measured in liver and kidney from normal and alloxan-diabetic rats. The long chain acyl CoA content was significantly increased in liver, but not in kidney, in the diabetic group. Adenine nucleotide translocase activity was decreased in liver and raised in the kidney of alloxan-diabetic rats relative to the control group. Pyruvate dehydrogenase (active) was inhibited to a similar degree in both tissues in diabetes. The results are discussed in the light of the possible regulatory role of long chain acyl CoA and the diverse metabolic demands of the two tissues in diabetes.
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PMID:Differential response of liver and kidney adenine nucleotide translocase and pyruvate dehydrogenase activity to alloxan diabetes. The possible regulatory role of long chain acyl CoA. 630 7


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