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)

Acute glucagon treatment of Rats has been found to increase in liver the intramitochondrial concentration of acetylglutamate which is an activator of carbamylphosphate synthetase l. A part of the stimulation of citrulline formation by glucagon is certainly related to this increase of acetylglutamate concentrations.
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PMID:[Role of acetylglutamate in the stimulation of citrullinogenesis by glucagon]. 678 Feb 19

The effects of dietary conditions on the degradation of hepatic N-acetyl-L-glutamate, an essential activator of carbamoyl phosphate synthase I [EC 6.3.4.16], were studied by injecting mice with [14C]glutamate and by following the fate of labeled N-acetyl-L-glutamate. In fasted mice, the radioactivity in N-acetyl-L-glutamate reached a maximum 10 min after injection and decreased rapidly with an apparent half-life of about 14 min. In mice fed on a 60% casein diet, the radioactivity in N-acetyl-L-glutamate increased up to 30 min and then decreased more slowly with an apparent half-life of about 60 min. The remarkably prolonged retention of the radioactivity in N-acetyl-L-glutamate in fed animals was not due to continued entry of the label into the compound but principally to an increase in the half-life of the compound. A protein-free diet failed to induce a similar response. Glucagon induced a retention of the radioactivity, though the extent was much less. When mitochondria from fasted rats were incubated at 25 degrees C, about 40% of N-acetyl-L-glutamate passed from the mitochondria to the medium in 60 min. On the other hand, the rate of efflux from the mitochondria of fed rats was comparable to that of fasted animals in spite of a 6-fold higher concentration of the compound in the mitochondria. The observations, together with previous results, indicate that N-acetyl-L-glutamate degradation is positively regulated by a modification of its efflux through mitochondrial membranes.
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PMID:Regulation of N-acetyl-L-glutamate degradation in mammalian liver. 706 75

Mitochondria isolated from livers of rats fed on different diets showed altered capacity to synthesize citrulline. Glucagon, 15 min after injection, increases citrulline biosynthesis, except after the high-protein diet. A significant correlation between citrulline biosynthesis and N-acetylglutamate content with and without glucagon treatment was shown when rats were fed on a standard or a carbohydrate diet. Different diets modified carbamoyl phosphate synthetase I (EC 6.3.4.16) and N-acetylglutamate synthase (acetyl-CoA:L-glutamate N-acetyltransferase, EC 2.3.1.1) activities. Glucagon did not modify these activities.
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PMID:Acute effects of glucagon on citrulline biosynthesis. 715 Feb 66

A single injection of glucagon increased the levels of all five urea cycle enzymes in 28-day-old rats, but had no significant effect in 35-day-old animals. Rats weaned onto diets varying in protein content showed rapid adaptation in the levels of carbamoylphosphate synthetase, which were complete 4 days after weaning. Induction of the enzyme by glucagon was independent of the diet. In animals subjected to a controlled feeding regime, no circadian variation in the levels of urea cycle enzymes could be observed. However, the inducibility of the enzyme by glucagon was greatest if the hormone was given near the beginning of the period of darkness and feeding.
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PMID:Control of urea cycle enzymes in rat liver by glucagon. 729 40

Transcription of genes for enzymes of the ornithine cycle is activated by hormones such as glucocorticoids and glucagon. Promoters and enhancers of several genes for the enzymes interact with the CCAAT/enhancer-binding protein (C/EBP) family of transcription factors, and C/EBPbeta has been suggested to mediate glucocorticoid response of the gene for arginase, the last enzyme of the cycle. To determine the contribution of C/EBPbeta to hormonal regulation of genes for ornithine cycle enzymes, we examined mice with targeted disruption of the C/EBPbeta gene. Induction of genes for the enzymes by intraperitoneal injection of dexamethasone and glucagon was almost intact in the liver of C/EBPbeta-deficient mice. On the other hand, in primary-cultured hepatocytes derived from C/EBPbeta-deficient mice, induction of genes for the first enzyme carbamylphosphate synthetase, as well as for arginase, in response to dexamethasone and/or glucagon was severely impaired. Therefore, C/EBPbeta is required for hormonal induction of the genes for ornithine cycle enzymes in primary-cultured hepatocytes, while the deficiency of C/EBPbeta is compensated for in vivo.
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PMID:CCAAT/enhancer-binding protein beta is required for activation of genes for ornithine cycle enzymes by glucocorticoids and glucagon in primary-cultured hepatocytes. 1129 44

The expression of carbamoylphosphate synthetase-I (CPS), the first and rate-determining enzyme of the urea cycle, is regulated at the transcriptional level by glucocorticoids and glucagon, the latter acting via cyclic AMP (cAMP). The hormonal response is mediated by a distal enhancer located 6.3 kb upstream of the transcription-start site. Within this enhancer, a cAMP-response unit (CRU) is responsible for mediating cAMP-dependent transcriptional activity. The CPS CRU contains binding sites for cAMP-response element (CRE)-binding protein (CRE-BP), forkhead box A (FoxA), CCAAT/enhancer-binding protein (C/EBP), and an unidentified protein P1. To gain insight in the protein-DNA interactions that activate the CPS CRU in living cells, we have employed in vivo footprinting assays. Comparison of the fibroblast cell line Rat-1 and the hepatoma cell lines FTO-2B and WT-8 showed that FoxA binds the CPS CRU constitutively in CPS-expressing cells only. Comparison of FTO-2B and WT-8 hepatoma cells, which only differ in cAMP responsiveness, demonstrated that the binding of the other transcription factors is dependent on cAMP-dependent protein kinase (PKA) activity. Finally, we observed a footprint between the CRE and the P1-binding site in the in vivo footprint assay that was not detectable by in vitro footprint assays, implying a major change in CRU-associated chromatin conformation upon CRU activation. These findings indicate that activation of the CRU is initiated in a tissue-specific manner by the binding of FoxA. When cellular cAMP and glucocorticoid levels increase, CRE-BP becomes activated, allowing the binding of the remaining transcription factors and the transactivation of the CPS promoter.
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PMID:In vivo footprinting of the carbamoylphosphate synthetase I cAMP-response unit indicates important roles for FoxA and PKA in formation of the enhanceosome. 1682 61