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)

In vivo administration of glucagon, insulin or epinephrine, respectively, gives rise to an increase of Ca++-retention time as well as of the Ca++-uptake rate in subsequently isolated rat liver mitochondria. Whereas the changes of Ca++-transport properties after pretreatment with glucagon or epinephrine occur already 6--15 min after their administration, the effect of insulin is observed not earlier than 30 min after its application. Under diabetic and starving conditions the Ca++-retention time of isolated liver mitochondria is prolonged, whereas no alteration of the uptake rate occurs. Since alloxan as well as streptozotocin induced qualitatively similar changes, a specific action of alloxan on liver mitochondria can be ruled out. Application of insulin 60--90 min prior to decapitation normalizes the changes of mitochondrial Ca++-transport observed under chronic alloxan diabetic conditions. Cycloheximide abolishes the prolongation of Ca++-retention in mitochondria from alloxan diabetic rats, but has no influence on the changes induced by glucagon pretreatment.
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PMID:Effect of in vivo and in vitro application of glucagon, insulin and epinephrine on Ca++-transport properties of liver mitochondria. 16 24

N6,O2'-dibutyrylcyclo-3',5'-AMP injected to intact rats alone or in combination with theophylline increases the activity of guanidine acetate methyltransferase (GAMT) in liver and pancreas. Cyclic 3',5'-AMP and its dibutyryl analog administered immediately or two hours after the suturing of common bile duct (SCBD) stimulate the increase of pancreatic GAMT activity 2-3 fold. Glucagon, injected intraabdominally simultaneously with SCBD and administration of theophylline, dramatically increases the theophylline effect on the GAMT activity. The freezing of rat pancreas pretreated witn secretin, a hormone structurally similar to glucagon, results in a 1.5-2-fold increase of creatine synthesis from S-adenosylmethionine and guanidinacetic acid. An hour after glucagon administration to intact rats the GAMT activity of liver increases 9 times. The effect of glucagon is enhanced by insulin. Cycloheximide inhibits the increase of GAMT activity, induced by glucagon or a combination of glucagon and insulin. Experiments on tissue homogenates demonstrate that 3',5'-AMP in concentrations of 10(-8) --10(-2) M does not affect the GAMT activity or to some extent inhibits the enzyme. The homogenate incubation in a medium containing 10(-5) M epinephrine or 10(-7) M caffeine and 5 mM Mg2+ leads to an increase in the GAMT activity. Oligomycin removes the stimulating effects of caffeine and Mg2+ on the enzyme activation. This is probably due to the presence of 3',5'-AMP-dependent protein kinase in the mechanism of GAMT activation by cyclic AMP.
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PMID:[The stimulating effect of cyclic AMP, glucagon and insulin on guanidine acetate-N-methyltransferase activity in rat liver and pancreas]. 17 11

No information is at present available on the mode of SRIF biosynthesis. Since anglerfish pancreatic islet tissue is comprised of approximately 30% D cells, we have examined this tissue for SRIF synthesis . The following known differences in amino acid composition of islet peptides were used advantageously in this study: anglerfish proinsulin: Trp-0, Ile-2, Cys-6; anglerfish glucagon: Trp-1, Ile-0, Cys-0; mammalian SRIF: Trp-1, Ile-0, Cys-2. After incubating islet tissue with [3H]tryptophan and [14C]isoleucine or [35S]cystine for various time periods, proteins were extracted in 2 M acetic acid and desalted by Bio-Gel P-2 gel filtration. P-2 void volume proteins were then subjected to P-10 gel filtration and isolated by polyacrylamide gel electrophoresis (PAGE) at alkaline pH. The predominant amount of the immumoreactive SRIF in the extracts appeared in a peak eluting just before the salt volume on P-10 filtration and migrated slowly toward the cathode during PAGE. The behavior of synthetic SRIF was identical. The anglerfish SRIF immunoreactive peptide could be labeled with Trp and Cys but not Ile during incubations longer than 1 h. The Trp- and Cys-labeled peptide could be bound on columns to which the immunoglobulin fraction of antisera to SRIF had been complexed. Cycloheximide inhibited isotope incorporation into all islet proteins. These results indicate that islet SRIF is synthesized in situ. Moreover, the immunological activity, size, and charge characteristics of anglerfish islet SRIF appear to be similar to those of mammalian hypothalamic SRIF. When islets were subjected to short pulse incubations with labeled Trp and Cys, only peptides eluting in the 7,000-13,000 dalton portion of the filtration eluate became labeled. No appreciable isotope incorporation into SRIF was observed. However, when pulse incubations were followed by incubation in the presence of cycloheximide or excess unlabeled amino acids in isotope-free medium (chase), the incorporation of Trp and Cys into SRIF increased with the length of chase, suggesting the participation of a larger precursor in SRIF synthesis.
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PMID:Somatostatin biosynthesis occurs in pancreatic islets. 36 32

The effects of insulin on amino acid transport were studied in freshly prepared suspensions of isolated hepatocytes from adult rats. Insulin stimulated the active transport of alpha-aminoisobutyric acid by increasing the influx. The onset of the insulin effect was delayed by thirty to sixty min. Insulin increased by Vmax of transport by about 60% without affecting the Km. Cycloheximide and actinomycin D inhibited hormonal action by 60 to 80%. Only the "A" system of transport was affected by insulin. Half-maximal stimulation of transport was observed with insulin at 2 to 3nmol/l, a concentration which also occupies about 50% of insulin-specific binding sites at steady state. Insulin did not antagonize the stimulatory effect of glucagon on amino acid transport.
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PMID:Effect of insulin on amino acid transport in isolated rat hepatocytes. 70 Feb 71

1. Isolated cat kidneys were perfused in situ with Locke solution and renin release in response to isoprenaline was studied. 2. Perfusion with isoprenaline produced a concentration-dependent enhancement of renin secretion. Increasing the concentration of stimulant also prolonged the duration of the secretory response. 3. After a 10 min exposure to isoprenaline (0-3 micrometer), there was a rapid facilitation of renin release which diminished after 10-30 min, followed by a second transient increase which declined over the next 40-60 min. Cycloheximide did not prevent augmented release when added together with the isoprenaline but did produce a reversible inhibition of the late phase when added 10 min after the isoprenaline. 4. Omission of calcium from the perfusion medium failed to depress the renin release induced by isoprenaline, glucagon, or furosemide. However, during prolonged calcium deprivation, the cycloheximide-sensitive phase of isoprenaline-evoked release was depressed. 5. The calcium antagonist D-600 failed to block the early phase of isoprenaline-induced renin secretion but inhibited the late phase of secretion. 6. Calcium alone elicited an explosive discharge of renin when added after a prolonged period of calcium-free perfusion. 7. These results support the view that extracellular calcium does not play an essential role in the mechanism of renin secretion from the renal juxtaglomerular cells, but that an increased influx of this cation is needed for synthesis and/or mobilization of the enzyme. It is tentatively proposed that the release of calcium from intracellular storage sites may be the signal which triggers renin secretion.
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PMID:The role of calcium in renin secretion from the isolated perfused cat kidney. 89 93

The effect of cycloheximide, an inhibitor of protein synthesis, on basal and stimulated renin secretion was examined in the isolated perfused rat kidney. Cycloheximide (0.05 mmol) was administered one hour before preparing the kidneys for perfusion. Both basal renin secretion and the response to intrarenal infusion of isoprenaline (0.06 nmol/min/g) or glucagon (0.1 nmol/min/g) were consistently reduced in the cycloheximide-treated group, suggesting dependence of these processes on protein synthesis.
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PMID:Suppression of renin secretion in the isolated rat kidney by cycloheximide. 99 24

Insulin responsiveness in the human placenta is controversial. This study evaluated insulin stimulation of alpha-aminoisobutyric acid (AIB) uptake in cultured human placental trophoblasts. Both Na(+)-dependent and -independent components of AIB uptake were present in cultured trophoblasts. Na(+)-dependent AIB uptake was significantly stimulated by insulin in a time-dependent manner, as early as 2 h, with a maximum at 12 h of continuous exposure to hormone. Insulin treatment for 4 h increased both the initial uptake rate and the final intracellular concentration. Stimulation was dependent on insulin concentration, with significant stimulation beginning at 10(-9) M. Insulin treatment increased maximum velocity but not the Michaelis constant. Approximately 75% of basal (unstimulated) AIB uptake was inhibited by 10 mM alpha-methylaminoisobutyric acid (MeAIB). The insulin-stimulated increment above basal AIB uptake was completely inhibited by 10 mM MeAIB. Cycloheximide treatment significantly reduced basal and stimulated AIB uptake, although a significant response to insulin persisted. Na(+)-dependent AIB uptake was also stimulated by glucagon, dexamethasone, and 8-bromoadenosine 3',5'-cyclic monophosphate, but not by vasopressin. This study further characterizes amino acid uptake by the human placenta and demonstrates that the Na(+)-dependent component of AIB uptake by the cultured trophoblasts is stimulated by physiological concentrations of insulin.
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PMID:Amino acid transport by the cultured human placental trophoblast: effect of insulin on AIB transport. 156 12

The transcriptional activity of the tyrosine aminotransferase (TAT) gene is influenced by two major signal transduction pathways, by glucocorticoids and by glucagon acting via cAMP. We analyzed the effect of cAMP on protein-DNA interactions in vivo and on the transcription rate of the TAT gene. We demonstrate that a cAMP-responsive element (CRE) is located in a tissue-specific DNase I-hypersensitive region, 3.6 kb upstream of the start site of transcription. By using the genomic footprinting technique, we show that this sequence is occupied by protein in uninduced cells and that the in vivo footprint is transiently increased upon cAMP induction. Protein binding at the TAT-CRE correlates with the rate of transcription of the TAT gene. Cycloheximide treatment reveals that the genomic footprint is subject to rapid turnover; however, subsequent cAMP induction in the continued presence of cycloheximide restores the footprint partially. We conclude that as a part of the signal transduction pathway, a cAMP-dependent, post-translational modification increases the DNA-binding activity of a protein to the TAT-CRE and thereby stimulates the transcription rate of the TAT gene.
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PMID:In vivo monitoring of a cAMP-stimulated DNA-binding activity. 197 62

We studied the effect of insulin, glucagon or dexamethasone on the production of insulin-like growth factor I (IGF-I) by cultured rat hepatocytes. Hepatocytes were isolated from normal adult rat livers and cultured in MEM, as nearly confluent monolayers. In the absence of such hormones, IGF-I and albumin accumulated in the culture medium almost linearly for periods up to 24 hours with the accumulation rates of 140 mU/mg cell protein per hour and 1.2 micrograms/mg cell protein per hour, respectively. Cycloheximide (5 micrograms/ml) almost completely inhibited the accumulation of IGF-I and albumin in the medium. Insulin at concentrations over 10(-10) M significantly inhibited the production of IGF-I in spite of the increased production of albumin. Conversely, glucagon stimulated the production of IGF-I at concentrations over 10(-8) M, but inhibited the production of albumin at concentrations over 10(-10) M. Dexamethasone stimulated the production of IGF-I at concentrations over 10(-7) M, but had no significant effects on the production of albumin. Thus, IGF-I production of hepatocytes is regulated by several hormones with different manner from albumin production.
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PMID:Effect of insulin, glucagon or dexamethasone on the production of insulin-like growth factor I in cultured rat hepatocytes. 206 Aug 98

Regulation of the expression of the hepatic L-type pyruvate kinase gene by insulin and dietary fructose was studied in diabetic rats. Insulin increased the levels of putative nuclear RNA precursor species of this enzyme in parallel with that of total cellular pyruvate kinase L mRNA. These changes occurred more slowly than those induced by dietary fructose. Insulin caused a 3-fold increase in transcription of the pyruvate kinase L gene after 6 h and a 6-fold increase after 16 h. The increase caused by insulin was inhibited by glucagon, but not by adrenalectomy. Cycloheximide inhibited the induction caused by insulin, suggesting that insulin may stimulate transcription of the pyruvate kinase L gene by stimulating synthesis of some unknown protein. On the other hand, feeding fructose had no effect on transcription of the pyruvate kinase L gene. We previously showed that increases in the levels of putative nuclear RNA precursor species of the pyruvate kinase L after fructose feeding preceded changes in the levels of cytosolic pyruvate kinase L mRNA (Inoue, H., Noguchi, T., and Tanaka, T. (1984) J. Biochem. (Tokyo) 96, 1457-1462). Thus, dietary fructose may increase the levels of pyruvate kinase L mRNA by stabilizing nuclear RNA species. Glucagon inhibited the increase in pyruvate kinase L mRNA caused by dietary fructose. However, plasma levels of glucagon and thyroid hormones were not decreased in diabetic rats after fructose feeding. In addition, treatment with triiodo-L-thyronine caused no change in the pyruvate kinase L mRNA level. Furthermore, adrenalectomy did not impair enzyme induction by fructose in diabetic rats. Thus, the effect of fructose on pyruvate kinase L seems to be directly on the liver.
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PMID:Transcriptional and post-transcriptional regulation of L-type pyruvate kinase in diabetic rat liver by insulin and dietary fructose. 241 97


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