Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present study the promoting activity of various PCB and PBB isomers and congeners in rat liver has been studied and compared with a variety of primary xenobiotic-mediated enzymatic changes in this target organ. Female Wistar rats were given diethylnitrosamine (DEN; 10 mg/kg body wt for 10 days) and were subsequently treated once weekly with polychlorinated biphenyls (150 or 15 mumol/kg body wt) for a total of 8 weeks. Additional groups of rats were administered 3,3',4,4'-tetrabromobiphenyl or 3-methylcholanthrene (8 weekly injections of 15 or 150 mumol/kg body wt, respectively) or were given phenobarbital (0.05% in the diet) until the end of the experiment. Reference groups were treated with the various test compounds without prior initiation. One week and 9 weeks after cessation of promoter treatment rats were killed and the volumetric fraction of enzyme-altered foci characterized by changes in adenosine triphosphatase and gamma-glutamyl transpeptidase activity was determined as a means to quantitatively assess the extent of preneoplastic response in this organ. Out of the series of polyhalogenated biphenyls tested, promoting effects were seen with the following compounds: 2,2',4,5'-tetrachlorobiphenyl, 3,3',4,4'-tetrachlorobiphenyl, 2,3,4,4',5-pentachlorobiphenyl, and 3,3',4,4'-tetrabromobiphenyl, whereas no significant effects were obtained with 4-monochlorobiphenyl. In rats not treated with DEN, the two strongly promoting agents 2,3,4,4',5-pentachlorobiphenyl and 3,3',4,4'-tetrachlorobiphenyl also significantly increased the volume fraction of enzyme-altered foci over the respective controls when analyzed at the second time point of investigation. In parallel experiments, induction of liver growth and of microsomal cytochrome P450 content in liver was found to correlate well with the promoting activity of the various xenobiotics, suggesting that these parameters may be used to predict the promoting activity of polyhalogenated biphenyls in a short term assay.
 ...
PMID:Effects of polychlorinated biphenyls in rat liver: correlation between primary subcellular effects and promoting activity. 168 70

Diethylnitrosamine was injected to Sprague-Dawley rats after a partial hepatectomy, and enzyme histochemistry analysis was made after 35 weeks in the preneoplastic liver. The areas and volumes of the induced enzyme-deficient islands were calculated for glucose-6-triphosphatase, adenosine triphosphatase, and 5'-nucleotidase. The preneoplastic enzyme-deficient zones showed also an increased incorporation of tritiated thymidine.
 ...
PMID:[Enzymatic phenotype of preneoplastic islands induced in the rat liver by diethylnitrosamine]. 610 Sep 68

Tea (Camellia sinensis) is one of the most widely used beverages worldwide and tea consumption has been shown to have an inverse correlation to the incidence of human cancers in epidemiological and experimental studies. In the present study, the protective effects of green tea polyphenols (GTP) and black tea polyphenols (BTP) in Wistar rats were assessed by medium-term bioassay, using altered hepatic foci (AHF) as end point. Animals were exposed to a single dose of diethylnitrosamine (DEN; 200 mg/kg body weight intraperitoneally), and GTP (1%) and BTP (1%) were then administered orally together with 0.05% 2-acetyl aminofluorene (2-AAF) crushed and mixed in the diet for 8 weeks. Numbers of AHF were scored and analyzed by quantitative stereology using the Image analysis system from frozen liver tissue sections. Tea polyphenol supplementation resulted in a significant protection against AHF induction in Wistar rats. In addition, levels of the positive biomarkers: gamma-glutamyl transpeptidase and glutathione-S-transferase (placental form) were reduced with GTP and BTP supplementation. Levels of the negative biomarkers adenosine triphosphatase and glucose-6-phosphatase were also restored by GTP and BTP administration. Thus, these results show the hepatoprotective effects of GTP and BTP against DEN- and 2-AAF-induced AHF development.
 ...
PMID:Inhibitory effect of tea polyphenols on hepatic preneoplastic foci in Wistar rats. 1905 50

Administration of diethylnitrosamine I.P. at dose level of 2 mg/kg five days a week to young Sprague-Dawley rats induced foci of altered hepatocytes entirely devoid of glucose-6-phosphatase and adenosine triphosphatase activity. Several weeks later, these foci developed hepatocellular carcinoma mostly of the trabecular type. Although these "preneoplastic" altered cells appeared as normal hepatocytes when examined in HE-sections, they were found to exhibit sites of dedifferentiation with ultrastructural features of hepatoma cells. Early morphological changes indicative of neoplastic transformation took place first as excessive storage of glycogen then as marked alterations at the surface membranes of such cells. Striking increase in coated pinocytotic vesicles appeared along the apposing cell membranes associated with loss of sinusoidal microvilli, protrusion of cytoplasmic blebs in the intercellular spaces, reduction or loss of desmosomes and obliteration of bile canaliculi. Subsequent changes were seen as dilation and disruption of the rough endoplasmic reticulum (RER), dispersal of ribosomes, proliferation and clustering of the smooth endoplasmic reticulum (SER), predominance of annulate lamellae, depletion of glycogen, enlargement of the Golgi cisterns and segregation of nucleolar elements. After 20 weeks, rats given DENA at a dose level of 25 mg/kg twice a week developed pronounced cirrhotic nodules in addition to multiple hepatocellular carcinoma. In contrast to the neoplastic nodules, the cirrhotic ones retained normal activity of glucose-6-phosphatase and adenosine triphosphatase and exhibited ultrastructural features typical of normal hepatocytes.
 ...
PMID:Ultrastructure of altered hepatocytes induced by diethylnitrosamine (DENA). 2809 9