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)

The quantity of translatable mRNA of glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ 1-oxidoreductase, EC 1.1.1.49) in primary cultures of adult rat hepatocytes subjected to different hormonal conditions was determined with a reticulocyte-lysate, cell-free system. The level of glucose-6-phosphate dehydrogenase mRNA was about 5-fold higher in the presence of insulin than in its absence. This increase of glucose-6-phosphate dehydrogenase mRNA reached a maximum 12 h after the addition of insulin. The maximum level of induction of glucose-6-phosphate dehydrogenase mRNA required 10(-8) M insulin. Glucagon and triiodothyronine had no effect on the glucose-6-phosphate dehydrogenase mRNA level. The increase of glucose-6-phosphate dehydrogenase activity correlated with the increase in level of mRNA of this enzyme. This suggests that the changes in glucose-6-phosphate dehydrogenase activity in response to the above hormonal changes are primarily due to changes in the amount of mRNA coding for this enzyme.
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PMID:Hormonal regulation of translatable mRNA of glucose-6-phosphate dehydrogenase in primary cultures of adult rat hepatocytes. 635 22

In primary cultured hepatocytes of adult rats epidermal growth factor (EGF) caused 2- to 3-fold induction of glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6P dehydrogenase) within 2 days. The effect of EGF was additive with a similar effect of insulin. The half-maximum dose of EGF for the induction was 1 ng/ml. Induction of this enzyme by these hormones was shown by immunotitration to be due to increase of the amount of enzyme. Furthermore, this increase in the amount of enzyme was found to result from increase of syntheses of mRNA and enzyme protein. In contrast, the induction of malic enzyme (EC 1.1.1.40, L-malate:NADP+) oxidoreductase) by insulin plus triiodothyronine was strongly suppressed by the concomitant addition of EGF. Induction of G6P dehydrogenase by EGF, like that by insulin, was not suppressed by either glucagon or dibutyryl cAMP, whereas that of malic enzyme was suppressed additively by EGF and dibutyryl cAMP. EGF also suppressed stimulation of lipogenesis by insulin, measured as incorporation of [1-14C]acetate into triglycerides and phospholipids. Another difference between the inductions of G6P dehydrogenase and malic enzyme was in their dependence on cell density; G6P dehydrogenase induction by insulin and EGF was high at low cell density (3 X 10(4) cells/cm2) and less at higher cell density (13 X 10(4) cells/cm2), whereas induction of malic enzyme was high at higher cell density and less at lower cell density. These results are consistent with the dual role of G6P dehydrogenase in lipogenesis in resting cells and in synthesis of nucleic acid in growing cells. Malic enzyme plays a role only for lipogenesis in mature hepatocytes.
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PMID:Reciprocal effects of epidermal growth factor on key lipogenic enzymes in primary cultures of adult rat hepatocytes. Induction of glucose-6-phosphate dehydrogenase and suppression of malic enzyme and lipogenesis. 635 85

Chronic fetal hyperinsulinemia, similar to that found in human infants of diabetic mothers, was produced in fetal rhesus monkeys during the latter third of gestation. Fetal plasma glucose and amino acid concentrations were found to be inversely logarithmically correlated with plasma insulin concentration. Fetal plasma glucagon concentrations were suppressed by hyperinsulinemia. Fetal plasma erythropoietin concentrations were increased by hyperinsulinemia in a dose/response manner. The activity of the hepatic gluconeogenic enzymes glucose-6-phosphatase and total phosphoenolpyruvate carboxykinase were reduced by hyperinsulinemia. Fatty acid synthase complex activity was, in contrast, increased by hyperinsulinemia while citrate cleavage enzyme and glucose-6-phosphate dehydrogenase were only increased when supraphysiologic hyperinsulinemia was produced. This model provides an opportunity to study the metabolic effects of hyperinsulinemia separate from those of hyperglycemia on the primate fetus, making it a useful model for the study of fetal pathologic conditions in diabetic pregnancies.
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PMID:Chronic hyperinsulinemia in the fetal rhesus monkey: effects of physiologic hyperinsulinemia on fetal substrates, hormones, and hepatic enzymes. 638 23

We studied the effects of glucagon (2 mg intravenously) on the histochemical localization and staining intensity of 10 enzymes in human gastric mucosa. Glucagon caused a significant increase in the histochemical activity of glucose-6-phosphate dehydrogenase in the undifferentiated neck cells and mucous cells of the foveolae and of ATPase activity in and around the mucosal capillary walls. Glucagon also stimulated mucus secretion from the surface epithelial cells. These changes were observed 15 and 30 min after glucagon in the oxyntic, but no pyloric mucosa. they indicate that glucagon, in addition to its effect on parietal cells, also affects other structures in human gastric mucosa.
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PMID:Effect of glucagon on human gastric mucosa: histochemical studies. 645 77

In primary cultured monolayer hepatocytes of adult rats, insulin (1 x 10(-8) M) induced glucose-6-phosphate dehydrogenase [EC 1.1.1.49, G6PDH] several fold in 48 h. It also induced lipogenesis, measured as [1-14C]acetate incorporation in 2 h, in these cells. Of the various lipids, triglycerides and phospholipids were induced markedly, while cholesterol and its esters were not induced. The increase of G6PDH and lipogenesis were parallel. Glucagon, dibutyryl cyclic AMP, triiodothyronine, dexamethasone, epinephrine, isoproterenol, and dibutyryl cyclic GMP were also tested under similar conditions, but none of them caused significant induction of G6PDH or lipogenesis. Use of anti-G6PDH serum showed that induction of G6PDH by insulin was due to increase in the amount of enzyme protein. Insulin was found to increase the rate of synthesis of G6PDH about 3-fold. SDS-polyacrylamide gel electrophoresis of the immunoprecipitable protein revealed that besides G6PDH another radioactive fraction (Mr 37,000) was increased by insulin. This suggests that complete synthesis of G6PDH protein is slowed down in primary cultured hepatocytes and that an apparent nascent peptide of the enzyme accumulates. Although on long-term treatment (48 h), glucagon and dibutyryl cyclic AMP had no effect on lipogenesis, when added with [14C]acetate for 2 h they strongly inhibited lipogenesis. Significant inhibition of lipogenesis by short-term treatment with glucagon was seen even in cells with a high capacity for lipogenesis induced by long-term treatment with insulin. Insulin again stimulated lipogenesis in short-term treatment, but its effect was slight. It is concluded from these results that insulin exerts long-term stimulation of lipogenesis by inducing enzymes related to lipogenesis including G6PDH as well as causing slight stimulation by enhancing supply of substrate for lipogenesis. Glucagon seems to play a minor role in long-term control, but it causes short-term inhibition of lipogenesis.
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PMID:Hormonal regulations of glucose-6-phosphate dehydrogenase and lipogenesis in primary cultures of rat hepatocytes. 704 Mar 64

A cytochemical bioassay for parathyroid hormone (PTH) was used for the characterization of the biological activity of circulating forms of the hormone. PTH-stimulated glucose-6-phosphate dehydrogenase activity in distal convoluted tubule cells was quantitated by integrating microdensitometry and the response to native bovine (b)PTH(1-84) was found to be linear between graded doses of hormone from 5 fg/ml to 5 pg/ml. Synthetic bPTH(1-34) and human (h)PTH(1-34) elicited a parallel and equimolar response; however calcitonin, ACTH, glucagon, epinephrine, vasopressin, and insulin failed to significantly stimulate the enzyme in doses up to 100,000 times greater than the lowest concentration of bPTH used. The assay was capable of distinguishing hormonal activity in normal, hypoparathyroid, and hyperparathyroid human plasma. After gel chromatography, bioactivity in plasma of hyperparathyroid patients with skeletal disease but normal kidney function coeluted mainly with bPTH(1-84), whereas bioactivity in plasma of hyperparathyroid patients with skeletal disease but severe uremia coeluted in approximately equivalent amounts with bPTH(1-84) and hPTH(1-34). Despite the abundance of small molecular-weight bioactivity in the peripheral circulation in uremia, approximately 85% of the bioactivity in the parathyroid venous effluent coeluted with bPTH(1-84). The results therefore demonstrate the sensitivity and specificity of the assay for PTH and its utility in measuring the hormone in human parathyroid disorders. The results furthermore demonstrate the importance of entities cochromatographing with bPTH(1-84) in comprising the circulating bioactive hormone in hyperparathyroidism, and support the concept of a biological role for smaller forms of PTH, at least in chronic renal failure.
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PMID:Cytochemical bioassay of parathyroid hormone: characteristics of the assay and analysis of circulating hormonal forms. 741 May 46

Previous studies have indicated that teleost fish appear to have two somatostatin genes. In salmonid fish, it is purported that gene I encodes for somatostatin-14 (SS-14), while gene II encodes for somatostatin-25 (sSS-25). In the present study, the physiological effects of SS-14 and sSS-25 on carbohydrate and lipid metabolism in rainbow trout, Oncorhynchus mykiss, were evaluated by in vivo administration of hormone and measuring resulting levels of specific metabolites and hormones present within tissues and plasma. Somatostatin-14 administration caused hyperglycemia without affecting liver glycogen content and increased plasma fatty acid (FA) levels in association with enhanced activity of the lipid mobilizing enzyme, triacylglycerol lipase (TG lipase). Somatostatin-14 injection also resulted in reduced hepatic glucose-6-phosphate dehydrogenase activity, which may indicate a decrease in glucose channeling through the pentose phosphate shunt. In addition, SS-14 reduced plasma glucagon concentration, while having no effect on plasma insulin levels. Salmon SS-25 elevated plasma glucose levels in association with reduced glycogen content and resulted in increased plasma FA levels accompanied by increased hepatic TG lipase activity. Salmon SS-25 injection also resulted in a reduction in plasma glucagon and insulin levels. These results indicate that SS-14 and sSS-25 are important regulators of carbohydrate and lipid metabolism in rainbow trout and that modulation of metabolic activity by these peptides may be accomplished, in part, by alterations in insulin and glucagon levels circulating in the plasma.
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PMID:Differential effects of somatostatin-14 and somatostatin-25 on carbohydrate and lipid metabolism in rainbow trout Oncorhynchus mykiss. 790 64

Hepatic glucokinase is induced by insulin and repressed by glucagon. The effects of epidermal growth factor (EGF) on glucokinase expression were investigated in rat hepatocytes. EGF does not affect the decline in glucokinase activity in hepatocytes cultured for 48h in the absence of insulin, but it counteracts the increase in activity induced by insulin. This effect of EGF is greater in cells cultured at low cell density than in confluent cultures. EGF suppressed the insulin-induced increase in glucokinase mRNA levels by 50% indicating that its effect is at least in part at a pretranslational level. However, it potentiated the stimulatory effect of insulin on glucose-6-phosphate dehydrogenase activity and mRNA, indicating that the effect on glucokinase expression is due to a specific post-receptor mechanism. The effect of EGF on glucokinase mRNA expression is mimicked by phospholipase D but not by phosphatidylinositol-specific phospholipase C or by phorbol ester, an activator of protein kinase C, suggesting that it is unlikely to be mediated by activation of protein kinase C.
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PMID:Epidermal growth factor counteracts insulin-induced expression of glucokinase in hepatocytes. 800 30

The culture of fetal hepatocytes at high cell density for 64 h in medium supplemented with 5 mM glucose produced an induction of glucose-6-phosphate dehydrogenase (G6PD) mRNA in a time-dependent manner. Insulin and triiodothyronine (T3), separately, increase G6PD mRNA expression, producing an additive effect at 64 h when combined. Glucagon and, to a greater extent, dibutyryl-cAMP decreased the G6PD mRNA expression observed in the presence of 5 mM glucose and T3. Dexamethasone repressed the G6PD mRNA expression induced by glucose and insulin and decreased this expression when induced by T3, regardless of the presence of insulin. At low cell density, EGF in the presence of dexamethasone induced in parallel DNA synthesis, G6PD mRNA content, and specific activity, while EGF failed to increase these parameters at high cell density. In addition, G6PD expression in proliferative fetal hepatocytes was unresponsive to lipogenic hormones.
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PMID:Glucose-6-phosphate dehydrogenase gene expression in fetal hepatocyte primary cultures under nonproliferative and proliferative conditions. 826 93

The release of glucokinase from digitonin-permeabilized hepatocytes shows different characteristics with respect to ionic strength and [MgCl2] from the release of other cytoplasmic enzymes. Release of glucokinase is most rapid at low ionic strength (300 mM sucrose, 3 mM Hepes) and is inhibited by increasing concentration of KCl [concn. giving half-maximal inhibition (I50) 25 mM] or Mg2+ (I50 0.5 mM). Release of phosphoglucoisomerase, phosphoglucomutase and glucose-6-phosphate dehydrogenase is independent of ionic strength, but shows a small inhibition by MgCl2 (20%, versus > 80% for glucokinase). Lactate dehydrogenase release increases with increasing ionic strength [concn. giving half-maximal activation (A50) 10 mM KCl] or [MgCl2]. The rate and extent of glucokinase release during permeabilization in 300 mM sucrose, 5 mM MgCl2 or in medium with ionic composition resembling cytoplasm (150 mM K+, 50 mM Cl-, 1 mM Mg2+) depends on the substrate concentrations with which the hepatocytes have been preincubated. In hepatocytes pre-cultured with 5 mM glucose the release of glucokinase was much slower than that of other cytoplasmic enzymes measured. However, preincubation with glucose (10-30 mM) or fructose (50 microM-1 mM) markedly increased glucokinase release. This suggests that, in cells maintained in 5 mM glucose, glucokinase is present predominantly in a bound state and this binding is dependent on the presence of Mg2+. The enzyme can be released or translocated from its bound state by an increase in [glucose] (A50 15 mM) or by fructose (A50 50 microM). The effects of glucose and fructose were rapid (t1/2 5 min) and reversible, and were potentiated by insulin and counteracted by glucagon. They were inhibited by cyanide, but not by cytochalasin D, phalloidin or colchicine. Mannose had a glucose-like effect (A50 approximately 15 mM), whereas galactose, 3-O-methyl-D-glucose and 2-deoxyglucose were ineffective. When hepatocytes were incubated with [2-3H, U-14C]glucose, the incorporation of 3H/14C label into glycogen correlated with the extent of glucokinase release. Since 2-3H is lost during conversion of glucose 6-phosphate into fructose 6-phosphate, substrate-induced translocation of glucokinase from a Mg(2+)-dependent binding site to an alternative site might favour the partitioning of glucose 6-phosphate towards glycogen, as opposed to phosphoglucoisomerase.
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PMID:Intracellular binding of glucokinase in hepatocytes and translocation by glucose, fructose and insulin. 828 78


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