Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(1) The rate of palmitate oxidation in the 7800 C1 Morris hepatoma cells was about 60% of the activity observed in hepatocytes. The stimulatory effect of glucagon in hepatocytes was not observed in the hepatoma cells. The rate of fatty acid synthesis from [2-14C]acetate in the hepatoma cells was 1/20 of the activity in hepatocytes. The conversion of [2-14C]acetate to cholesterol was not different in the two kinds of cell. (2) Acetyl-CoA carboxylase and fatty acid synthetase were significantly decreased in the hepatoma cells. The hepatoma cells had, however, raised activities of malate dehydrogenase (decarboxylating), and glucose-6-phosphate and 6-phosphogluconate dehydrogenases. (3) The activities of the enzymes were not affected by different concentrations of glucose or palmitate in the culture medium. Insulin, dexamethasone, triiothyronine and glucagon had no effect on the enzyme activities. This is in contrast to the adaptation of the peroxisomal beta-oxidation system, which is induced by fatty acids and modified by hormones.
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PMID:Activities of enzymes of lipid metabolism in Morris hepatoma 7800 C1 cells. 256 35

1. Concentrations of glucose 6-phosphate and 6-phosphogluconate were studied in islets of Langerhans isolated from rat pancreas and incubated in the presence of various agents that induce insulin release. 2. In response to rising concentrations of extracellular glucose (2-10mm) there is a linear increase in the intracellular concentration of glucose 6-phosphate, though this is not the case for 6-phosphogluconate, the intracellular concentration of which only increases when the external glucose concentration exceeds 5mm. 3. Tolbutamide, octanoate and citrate, all of which promote insulin secretion from isolated islets, increase the intracellular concentrations of glucose 6-phosphate and 6-phosphogluconate. The results obtained in the presence of octanoate and citrate are compatible with an inhibitory effect of citrate on islet-cell phosphofructokinase. 4. Theophylline and glucagon when incubated with islets in vitro promote insulin release and cause a rise in 6-phosphogluconate concentration and not in that of glucose 6-phosphate. 5. It is suggested that the further metabolism of glucose 6-phosphate through a pathway other than glycolysis is essential for insulin release. One such pathway involves its oxidation to 6-phosphogluconate, which seems to be a necessary accompaniment of insulin secretion due to glucose. The possibility that agents other than glucose promote insulin release by enhancing the oxidation of glucose 6-phosphate through this pathway is discussed.
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PMID:Islet-cell metabolism during insulin release. Effects of glucose, citrate, octanoate, tolbutamide, glucagon and theophylline. 424 86

Isolated liver parenchymal cells from rats fed a 65% sucrose diet for 14 days were incubated in the presence and absence of 10(-6) M glucagon. The pyruvate kinase obtained from homogenates of the glucagon-treated cells displayed and increased Ks 0.5 for phosphoenolpyruvate (P-enolpyruvate), as well as an increased Ka 0.5 for 6-phosphogluconate (6-P-gluconate), compared to pyruvate kinase from untreated cells. Additionally, glucagon treatment decreased the maximal stimulation of pyruvate kinase by 6-P-gluconate by approximately two-thirds and decreased the Hill coefficient value of pyruvate kinase for 6-P-gluconate from 1.76 to 1.56. 6-Aminonicotinamide, an inhibitor of 6-P-gluconate dehydrogenase, increased 6-P-gluconate levels in isolated liver parenchymal cells three- to sevenfold, depending on the substrates present. The flux of P-enolpyruvate through pyruvate kinase was increased from 18 to 40% in these preparations and was highly correlated with the increase in 6-P-gluconate levels. The results suggest that 6-P-gluconate could regulate pyruvate kinase activity in the intact liver parenchymal cell. Furthermore, the activator would be of greatest importance in the lipogenic animal.
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PMID:Regulation of pyruvate kinase by 6-phosphogluconate in isolated hepatocytes. 721 60