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)

To explore a possible role of acylphosphatase in the regulation of energy metabolism, we measured this enzyme's activity and content in skeletal muscle, liver and erythrocytes of normal and tri-iodothyronine treated rabbits. Besides acylphosphatase we assayed (Na+ + K+)-ATPase, Ca2(+)-ATPase and several enzymes of carbohydrate metabolism. Acylphosphatase activity in erythrocytes rose steadily during treatment with triiodothyronine (25 micrograms/Kg per day for 5 weeks), and its increase occurred earlier and was much more pronounced than that of other soluble enzymes. In erythrocytes of treated animals (Na+ + K+)-ATPase declined whereas Ca2(+)-ATPase activity increased, in agreement with previously reported findings. In muscle and liver of the treated animals acylphosphatase activity was about twice as high as in the controls; in these tissues we found also increased activities for (Na+ + K+)-ATPase, fructose-1,6-bisphosphatase and glucose-6-phosphatase. In any case, among the enzymes we examined, acylphosphatase was one of the most strongly and regularly stimulated by the treatment. Furthermore we observed, through an immunochemical procedure, that there was a congruence between increases in acylphosphatase activity and content. On the basis of these results we conclude that the rise in acylphosphatase levels in treated animals is probably due to its increased biosynthesis. The possible significance of these findings in the metabolic modifications associated with hyperthyroidism are discussed.
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PMID:Increased acylphosphatase levels in erythrocytes, muscle and liver of tri-iodothyronine treated rabbits. 215 65

Four fibrolamellar liver carcinomas were surgically removed and were postoperatively examined. Three patients are alive roughly three years from surgery, and there are no signs of imminent recurrence, while the fourth case was diagnosed only two months back. The carcinomas had developed in non-cirrhotic livers which also produced negative responses to serological tests for hepatitis B. In flow cytometry, DNA indices were indicative of diploidy in two cases and aneuploidy in the other two. The highest DNA index value was recorded from the smallest tumour which could be assigned to the category of "minute HCC". No correlation was found to exist either between age, sex, and DNA index. Positive CEA reaction was immunohistochemically recorded from few tumour cells, whereas negative AFP responses were exhibited by all four tumours. Appearance of AAT in tumour cells was detected in three cases. High degree of differentiation, similarity between tumour and liver cells, and oncocytoid nature of cells were revealed by optical light and electron microscopy. This high degree of differentiation was additionally confirmed by two factors: glucose-6-phosphatase activity was preserved in all four tumours, adenosinetriphosphatase activity was histochemically detectable from certain points of the tumour cell membrane. Gamma-glutamyl-transpeptidase activity, too, was very strongly pronounced in all tumour cells, which, however, cannot be interpreted as a sign of differentiation. Membrane-bordered "dense-core" granules were visible in few tumour cells in two cases. Intensive granular serotonin reactions were immunohistochemically recorded from the majority of tumour cells in the same cases. Our histochemical and ultrastructural parameters have produced clear-cut evidence to the hepatocyte nature of FLC cells. Yet, the presence of secretory granules and positive serotonin reaction might possibly support the assumption that the FLC originates from those pluripotent cells of the liver which may develop in two directions, depending on the individual case, to become either hepatocytes or neurosecretory cells.
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PMID:[Fibrolamellar liver carcinoma]. 215 93

Liver endothelial cells form a continuous lining of the liver capillaries, or sinusoids, separating parenchymal cells and fat-storing cells from sinusoidal blood. Liver sinusoidal endothelial cells differ in fine structure from endothelial cells lining larger blood vessels and from other capillary endothelia in that they lack a distinct basement membrane and also contain open pores, or fenestrae, in the thin cytoplasmic projections which constitute the sinusoidal wall. This distinctive morphology supports the protective role played by liver endothelium, the cells forming a general barrier against pathogenic agents and serving as a selective sieve for substances passing from the blood to parenchymal and fat-storing cells, and vice versa. Sinusoidal endothelial cells, furthermore, significantly participate in the metabolic and clearance functions of the liver. They have been shown to be involved in the endocytosis and metabolism of a wide range of macromolecules, including glycoproteins, lipoproteins, extracellular matrix components, and inert colloids, establishing endothelial cells as a vital link in the complex network of cellular interactions and cooperation in the liver. Fine structural studies in combination with the development of cell isolation and culture techniques from both experimental animal and human liver have greatly contributed to the elucidation of these endothelial cell functions. Morphological and biochemical investigations have both revealed little changes with age except for an accumulation of iron ferritin and a decrease in the activities of glucose-6-phosphatase, Mg-ATPase, and in glucagon-stimulated adenylcyclase. Future studies are likely to disclose more fully the role of sinusoidal endothelial cells in the regulation of liver hemodynamics, in liver metabolism and blood clearance, in the maintenance of hepatic structure, in the pathogenesis of various liver diseases, and in the aging process in the liver.
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PMID:Sinusoidal endothelial cells of the liver: fine structure and function in relation to age. 218 63

The ability of methyl-deficient, amino-acid-defined diets to produce enzyme-altered foci was quantitatively determined in the livers of rats treated both with and without an initiating dose of diethylnitrosamine (DEN). Male weanling F-344 rats were fed a complete, amino-acid-defined diet for 1 week. They were then injected i.p. with a single dose of DEN (20 mg/kg body weight) and fed the complete diet for an additional week. Forty animals in each dose group were then maintained for 5-38 weeks on the complete diet (diet 1) or one of the three methyl-deficient diets customarily used in this laboratory: diet 2, devoid of methionine and choline; diet 3, devoid of methionine only; and diet 4, devoid of choline only. In diets 2 and 3, methionine was replaced by equimolar amounts of its metabolic precursor, DL-homocystine. Ten animals per group were killed 8, 12, 17, 24 and 41 weeks after DEN initiation. For 2 weeks prior to being killed, each group was maintained on the complete diet to minimize the histological abnormalities due to acute toxicity of the diets. Serial sections of the livers were obtained, stained sequentially for gamma-glutamyltranspeptidase, ATPase and glucose-6-phosphatase, and the quantitation of the focal lesions scored by these markers was carried out by quantitative stereology. The results indicated that, regardless of the enzyme marker(s) examined, there was a general correspondence between the volume and number of altered hepatic foci (AHF) formed and the previously described tumor-promoting activities of each diet. Thus, while all DEN-treated groups contained significant numbers of AHF 24 weeks after initiation, only the diet-2-fed animals displayed such foci at 8 weeks. Similarly, among the uninitiated rats, only those fed diet 2 exhibited the presence of AHF throughout the experimental period. Interestingly, the livers of uninitiated, choline-deficient rats showed a small number of AHF at 24 and 42 weeks; these foci were not observed at all in the corresponding DEN-untreated animals fed diet 3, deficient in methionine only. The results provide evidence that the carcinogenic effects of the methionine- and choline-deficient diet result more from its strongly promoting effect than from any initiating activity by the diet.
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PMID:The effect of choline and methionine deficiencies on the number and volume percentage of altered hepatic foci in the presence or absence of diethylnitrosamine initiation in rat liver. 230 54

Microsomes from ventral prostate of 24-h castrated rats contain a single set of tissue-specific high-affinity, low-capacity androgen binding sites. These sites are indigenous to the endoplasmic reticulum, as shown by purification procedures associated with marker enzymes and electron microscopic analyses. When prostatic microsomal membranes are separated from plasma membranes using the nuclear or the mitochondrial pellets as the source of fractionation in sucrose gradients, the androgen binding activity is selectively associated with fractions rich in rough endoplasmic reticulum and ribosomes. Eighty-four percent of the total content of Na+/K+ adenosine triphosphatase (ATPase) and only 27% of the total binding capacity were concentrated in fractions rich in smooth-surfaced vesicular membranes, when nuclear suspensions constituted the membrane source. In contrast, the region of the same gradient when enriched in rough endoplasmic reticulum and deficient in plasma membrane content contained 73% of the androgen-binding capacity and only 14% of the ATPase. For fractions collected using mitochondrial suspensions as starting material, the ratio (total glucose-6-phosphatase/total binding capacity) was closer to 1.0 than similar ratios of ATPase/binding capacity, indicating co-sedimentation of binding sites with microsomal membranes and not with plasma membranes. Na+/K+ ATPase, but not 5' nucleotidase, is a valid plasma membrane marker for ventral prostate. Microsomal androgen receptors may constitute a new level of regulation of androgen action in target cells.
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PMID:Association of androgen binding sites with the endoplasmic reticulum of rat ventral prostate. 233 29

Neuropathy target esterase (NTE) is the suggested "target" molecule involved in the initiation of organophosphorus-induced delayed polyneuropathy. Sciatic nerve NTE was separated into particulate (P-NTE) and soluble (S-NTE) fractions by ultracentrifugation at 100,000 g for 1 h in 0.32 M sucrose and compared with the corresponding brain extract. Total sciatic NTE activity was 80-100 nmol/min/g tissue from which 50-60% was recovered in the soluble supernatant fraction and the remaining 40-50% in the pellet fraction. About 90% of brain tissue activity (approximately 1,800 nmol/min/g tissue) was recovered as P-NTE. A similar distribution was obtained when more drastic centrifugation without sucrose was performed. P-NTE and S-NTE were distributed with the membrane and cytosolic markers assayed, respectively, glucose-6-phosphatase, Na+,K(+)-ATPase, 5'-nucleotidase, phospholipids, and lactate dehydrogenase. When the pH during the centrifugation was increased from 6.4 to 11, recovered P-NTE activity decreased from 1,750 to 118 nmol/min/g tissue for brain and from 31 to 12 nmol/min/g for sciatic nerve. However, S-NTE activity and total nonfractionated control activity were only slightly affected by the same pH treatment. The distribution pattern encountered may be better understood as representing two different proteins than an equilibrium between soluble and membrane-bound portions of a single protein, with P-NTE activity depending on a membrane factor from which it is separated through fractionation at high pH.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Soluble and particulate forms of the organophosphorus neuropathy target esterase in hen sciatic nerve. 239 58

The relationships between the gross appearance, histologic types, and cytochemical characteristics of hepatocellular neoplasms were studied in B6C3F1 mice given the liver carcinogen diethylnitrosamine either alone or followed by the organochlorine pesticides, 4,4'-dichlorodiphenyltrichloroethane, chlordane, or heptachlor as promoting agents. Hepatocellular neoplasms were categorized according to their cytoplasmic staining properties with hematoxylin and eosin. Acidophilic neoplasms more often displayed increased activity of alkaline phosphatase than did basophilic neoplasms. The activities of glucose-6-phosphatase and adenosine triphosphatase were decreased in both acidophilic and basophilic neoplasms. There was no difference in the activities of these enzymes or gamma-glutamyltranspeptidase between adenomas and carcinomas, although most neoplasms did not display gamma-glutamyltranspeptidase. Chlordane or heptachlor exposure increased the alkaline phosphatase activity in neoplastic cells, but not that of other enzymes. The majority of neoplasms displayed a deficiency of iron accumulation. The macroscopic appearance of neoplasms was closely related to their cytoplasmic staining properties and cytochemical characteristics.
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PMID:Morphologic and cytochemical properties of mouse liver neoplasms induced by diethylnitrosamine and promoted by 4,4'-dichlorodiphenyltrichloroethane, chlordane, or heptachlor. 242 23

A 30-day ingestion of gamma-hexachlorocyclohexane (lindane) by carp (Cyprinus carpio) induced hypoglycemia without activation of two hepatic gluconeogenesis enzymes (fructose diphosphatase, EC 4.1.2.13, and glucose-6-phosphatase, EC 3.1.3.9) and hyponatremia and variations in muscle plasmic membrane-bound enzymes (especially cholinesterases, EC 3.1.1.7). After 109 days carps exhibited a decrease in natremia but no significant hypoglycemia. There was an activation of gluconeogenesis enzymes. Important changes were observed in the activities of muscle plasmic membrane enzymes (especially 5'-nucleotidase, EC 3.1.3.5, and ATPases, EC 3.6.1.3). Lindane, a lipophilic substance, especially disturbed the activity of membrane-bound enzymes enclosed in a phospholipid matrix.
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PMID:Effect of gamma-hexachlorocyclohexane (lindane) on carp (Cyprinus carpio). II. Effects of chronic intoxication on blood, liver enzymes, and muscle plasmic membrane. 244 Jun 61

Administration of beta- and gamma-isomers of hexachlorocyclohexane (HCH) at 800 ppm dietary level for 2 weeks to albino rats produced noticeable hepatocellular damage as indicated by elevations in serum aminotransferases and decreases in hepatic soluble enzymes. Although serum total LDH activity was not altered, the LD5 isoenzyme was proportionately higher in the HCH isomers treated animals. Treatment of rats with beta- and gamma-isomers of HCH increased the hepatic glucose-6-phosphate dehydrogenase and aldolase activities suggesting a higher rate of glucose oxidation. Liver glucose-6-phosphatase activity was decreased in these animals indicating inactivation of gluconeogenesis in liver. Dietary beta- and gamma-HCH decreased the liver mitochondrial DNP/Mg++/Ca++-activated ATPases thus affecting the energy metabolism. An unaltered ratio of DNP/Mg++-ATPase, a study of swelling pattern of hepatic mitochondria, and NAD+ permeability test suggested the maintenance of structural integrity of mitochondrial membrane in these pesticide fed animals. Liver microsomal Na+,K+-ATPases were lower in these animals.
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PMID:Biochemical changes produced by beta- and gamma-hexachlorocyclohexane isomers in albino rats. 246 8

In order to study the characteristics of the intracellular Ca store of mast cells, organelles of rat peritoneal mast cells were fractionated. The binding of 45Ca was at its peak in the fractions where the highest activity of glucose-6-phosphatase, the marker enzyme for the endoplasmic reticulum (ER), was measured. The ER-rich fraction exhibited an ATP-dependent uptake of 45Ca and this uptake was inhibited by pretreatment with ATPase inhibitors such as LaCl3 or Na3VO4. When inositol 1,4,5-trisphosphate (IP3) was added to a medium containing the 45Ca-loaded ER fraction, it caused a dose-dependent release of 45Ca at concentrations higher than 0.5 microM, while inositol 1-monophosphate and inositol 1,4-bisphosphate were not effective even at higher concentrations. The results of a binding assay using 3H-labeled IP3 indicated that there exist two kinds of IP3 binding site in the ER: one is of high affinity but low capacity while the other is of low affinity and high capacity. IP3-induced 45Ca release was dose-dependently inhibited by pretreatment with c-AMP. The present study supports the assumption that the intracellular Ca store associated with histamine release from the mast cell is the ER.
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PMID:Ca uptake and Ca releasing properties of the endoplasmic reticulum in rat peritoneal mast cells. 246 54


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