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)

Glucose-6-phosphatase is a multicomponent endoplasmic reticulum system comprising at least six different proteins, including a lumenal enzyme and several transport proteins. One of the transport proteins, T2beta, transports the substrate pyrophosphate and the product phosphate and its genetic deficiency is termed type 1c glycogen storage disease. We have used anti-T2beta antibodies for immunohistochemistry with image analysis and kinetic analysis of the glucose-6-phosphatase system to study for the temporal and spatial development of T2beta in human embryonic and fetal kidney. In metanephric kidney, there is an early predominance of T2beta expression in the ureteric bud derivatives and this changes with ontogeny such that developing nephrons, particularly proximal tubules, become dominant by mid-gestation. T2beta has the same spatial and temporal pattern as the glucose-6-phosphatase enzyme in both mesonephric and metanephric kidney. Pyrophosphate transport capacity is appropriate for the amount of glucose-6-phosphatase activity present in mid-gestation fetal kidney, in contrast to liver, where pyrophosphate transport capacity is developmentally delayed. Increasing knowledge of the temporal and spatial expression of the glucose-6-phosphatase proteins and their catalytic roles in early human development is essential for the elucidation of the aetiology of renal disease in both type I glycogen storage diseases and the developmental disorders of the glucose-6-phosphatase system.
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PMID:The human embryonic-fetal kidney endoplasmic reticulum phosphate-pyrophosphate transport protein. 860 68

The mRNA and the activity of glucose-6-phosphatase (Glc-6-Pase) were present in the liver, kidney, and small intestine of 15-day-old suckling rats, but were absent from the stomach, colon, lung, white and brown adipose tissues, muscle, heart, brain, and spleen. The mRNA encoding Glc-6-Pase was present in the liver of 21-day-old fetal rats and increased markedly immediately after birth. From 5 days after birth to the end of the suckling period, it returned to 50% of the level found in the liver of 48-h starved adult rats. When rats were weaned at 21 days onto a high-carbohydrate, low-fat (HCLF) diet, the concentration of liver Glc-6-Pase mRNA was markedly increased. In the fetal rat jejunum, the activity and mRNA of Glc-6-Pase were very low. It increased during the 5 days after birth and then declined to reach very low levels. Neither mRNA nor activity of Glc-6-Pase was present in the fetal kidney. They appeared and increased slowly during the suckling period to reach maximal levels 15 days after birth and then remained constant. Weaning onto the HCLF diet did not change the Glc-6-Pase gene expression, neither in the jejunum nor in the kidney. The regulation of Glc-6-Pase gene expression by hormones and nutrients was studied in cultured hepatocytes from 20-day-old rat fetuses. Bt2cAMP stimulated the Glc-6-Pase gene expression in a dose-dependent manner. This probably resulted from an increased gene transcription since the half-life of the transcript was not affected by dibutyryl cAMP (Bt2cAMP). The Bt2cAMP-induced Glc-6-Pase mRNA accumulation was antagonized by insulin in a dose-dependent manner. Long-chain fatty acids (LCFAs), but not medium-chain fatty acids, induced the accumulation of Glc-6-Pase mRNA and the stabilization of the transcript. The peroxisome proliferator, clofibrate, induced a threefold increase in Glc-6-Pase mRNA concentration. Both stimulation of Glc-6-Pase mRNA by LCFAs and clofibrate were inhibited by insulin. Increasing concentrations of glucose (from 0 to 20 mmol/l) did not affect the Bt2cAMP-induced Glc-6-Pase gene expression. By contrast, high glucose concentration (25 mmol/l) markedly induced the Glc-6-Pase gene expression in fed adult rat hepatocytes. The difference in the response to glucose between fetal and adult rat hepatocytes is discussed. We conclude that the rapid increase in hepatic Glc-6-Pase mRNA levels that accompanies the fetal-to-neonatal transition in the rat is triggered by the reciprocal change in circulating insulin and LCFA concentrations, coupled to the rise in liver cAMP concentration.
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PMID:Development and regulation of glucose-6-phosphatase gene expression in rat liver, intestine, and kidney: in vivo and in vitro studies in cultured fetal hepatocytes. 960 63