Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.9 (glucose-6-phosphatase)
 3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Xenopus laevis (Daudin) adult specimens were submitted to hypophysectomy. Although the operation resulted subtotal, it served the purpose of removing the prolactin-producing cells, whereby the involvement of endogenous prolactin in osmoregulation phenomena was excluded. In the operated animals treated with ovine prolactin the following metabolic parameters, which are closely dependent upon interrenal activity, were estimated: 1) intestine alkaline phosphomonoesterase activity (E.C. 3.1.3.1); 2) liver glycogen level; 3) glucose-6-phosphatase (E.C. 3.1.3.9.) and phosphoenolpyruvate carboxykinase (E.C. 4.1.1.32.) in the liver; 4) blood glucose level; 5) blood ammonia and urea levels; 6) carbamoylphosphate synthetase activity in the liver (E.C. 2.7.2.a); 7) muscle sodium and potassium levels. The above metabolic parameters were found to be pressed by subtotal hypophysectomy and after subsequent prolactin treatment showed the tendency to go back to values similar to those of control animals.
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PMID:Biochemical data on subtotally hypophysectomized Xenopus laevis (Daudin) adult specimens treated or not with prolactin. 21 25

The liver is the "glucostat" of the organism and serves at the same time as an "ammonia-sink and pH stat". The key enzymes involved in glucose uptake and release and in urea and glutamine formation are reciprocally distributed over the liver parenchyma: The glucogenic enzymes phosphoenolpyruvate carboxykinase (PEPCK), fructosebisphosphatase (FBPase) and glucose-6-phosphatase (G6Pase) as well as the ureagenic enzyme carbamoylphosphate synthetase (CAPS) are predominant in the periportal zone. The glycolytic enzymes glucokinase (GK) and pyruvate kinase type L (PKL) as well as the glutaminogenic enzyme glutamine synthetase (GluNS) are prevalent in the perivenous zone. This heterogeneity appears to be a prerequisite for the normal "glucostat, ammonia-sink and pH-stat" function of the liver. After birth the liver is a gluconeogenic organ, only with weaning it becomes a "glycolytic/gluconeogenic" glucostat. In the rat zonation of PEPCK, G6Pase and CAPS developed gradually after birth and was completed before weaning, i.e. before it would be functionally required. After 2/3 partial hepatectomy the liver looses its normal glucostat function and becomes a gluconeogenic organ. With this change the zonation of PEPCK and PKL were also lost; it was restored only during the second week after operation. During starvation the liver also looses its glucostat function to become the major glucose supplier of the organism. Zonation of PEPCK and PKL were diminished to such an extent that the major function of the perivenous zone was altered from glucose uptake to release. In diabetes the liver does not loose its glucostat function; however, the function is severely impaired. Zonation of PEPCK was increased and that of PKL decreased in such a manner that the major function of the perivenous zone, glucose uptake, was not entirely changed but only diminished. It can be concluded that in the various physiological states studied the zonation of enzymes correlated well with the glucostat function of the liver.
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PMID:Dynamics of zonal hepatocyte heterogeneity. Perinatal development and adaptive alterations during regeneration after partial hepatectomy, starvation and diabetes. 301 Mar 76

Transdifferentiation of pancreas to liver is a well-recognized phenomenon and has been described in animal experiments and human pathology. We recently produced an in vitro model for the transdifferentiation (or conversion) of the pancreatic cell line AR42J-B13 to hepatocytes based on culture with dexamethasone (Dex). To determine whether the hepatocytes express markers of hepatic intermediary metabolism and detoxification, we investigated the patterns of expression of glucokinase, cytochrome P450s CYP3A1 and CYP2B1/2, testosterone/4-nitrophenol uridine diphosphate glucuronosyltransferase (UDPGT), and aryl sulfotransferase. All were expressed. We also determined the expression of 2 enzymes involved in ammonia detoxification: carbamoylphosphate synthetase I (CPS I) and glutamine synthetase (GS). These enzymes are normally strictly compartmentalized in liver in a wide periportal pattern and the last downstream perivenous hepatocytes, respectively. Following culture with Dex, CPS I and GS are expressed in 2 different cell populations, suggesting that both periportal and perivenous hepatocytes are induced. We also produced a reporter assay based on the activation of green fluorescent protein (GFP) by the transthyretin (TTR) promoter or glucose-6-phosphatase (G6Pase) promoter. After culture with Dex, transfected cells begin to express GFP, showing that hepatic promoters are activated in concert with the induction of the hepatocyte phenotype. Lastly, we examined the stability of the hepatic phenotype and found that some cells still express liver markers (transferrin or albumin) up to 14 days after removal of Dex. In conclusion, these results suggest that pancreatic hepatocytes produced by this method may offer an alternative model to primary cultures of hepatocytes for the study of liver function.
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PMID:Differentiated properties of hepatocytes induced from pancreatic cells. 1219 45