Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The relation of endotoxicosis to insulin responsiveness was evaluated in male Holtzman rats. Salmonella enteritidis lipopolysaccharide at 0.5 or 1.0 mg per 300 g rat increased lethality in convulsive seizure deaths to 0.25, 0.50, or 1.0 U insulin sc. The hypoglycemic nadir induced by 0.05, 0.10, or 0.25 U of insulin sc was greater in rats rendered endotoxic with 1 mg of lipopolysaccharide IV. Oxidation of U-14C-D-glucose to 14 CO2 by endotoxic tissues in vitro was augmented in liver slices, epididymal fat pads, hemidiaphragms, and spleen slices; no pronounced glucose oxidation increases occurred in lung, heart, stomach, cerebrum, kidney, or whole blood. Epididymal fat pads from endotoxic rats (100 g) manifested increased basal glucose oxidation as well as an enhanced maximal response to incremental insulin doses of 0.01 to 25 mU/ml. It is suggested that altered tissue responsiveness in concert with hyperinsulinemia underlie the profound alterations in glucose homeostasis during endotoxicosis.
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PMID:Increased insulin responsiveness in endotoxicosis. 37 53

Activation of protein kinase C (PKC) by bacterial lipopolysaccharide had recently been implicated in the pathogenetic sequence of gram-negative sepsis, endotoxicosis, hyperinsulinism, and the alterations in glucoregulation that eventuate in glucose dyshomeostasis. This study used the peptide antibiotic polymyxin B (PMX-B) and H-7, an isoquinoline sulfonamide, as inhibitors of PKC activation to evaluate responses to provocative insulin and glucose tolerance tests in control vs. endotoxic rats. Fed male rats were treated with either Salmonella enteritidis endotoxin (ETX; 0.33 mg/kg iv) or saline 120 min before intravenous insulin tolerance testing (IVITT) with human insulin (1 U/kg) or intravenous glucose tolerance testing (IVGTT) with D-glucose (1.2 g/kg). H-7 in dimethyl sulfoxide at 25 mg/kg, PMX-B in saline at 0.25 mg/kg, or the respective vehicles were administered 5 min before the tolerance tests. Neither H-7 nor PMX-B had any significant acute effects on basal plasma glucose or lactate values. The decline in plasma with IVITT was augmented by ETX; however, concomitant H-7 or PMX-B attenuated the insulin hypoglycemia. The computed half-life of glucose in the IVGTT was decreased by ETX; however, concomitant H-7 or PMX-B decreased the tolerance alteration. In addition, both H-7 and PMX-B attenuated the rise in insulin induced by the IVGTT. Thus the hyperinsulinism and the glucoregulatory disturbances in endotoxicosis may be mediated by PKC activation and ameliorated by PKC inhibition.
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PMID:Antagonism of endotoxic glucose dyshomeostasis by protein kinase C inhibitors. 185 53

The administration of a potent activator of macrophages (M phi), Propionibacterium acnes, in nondiabetic mice was associated with the release of significant amounts of interleukin-1 (IL-1) in the peritoneal cavity and plasma within 4 hours after treatment. Shortly before IL-1 peaks were observed, the levels of pancreatic insulin, [3H]leucine-proinsulin, and insulin/total protein ratio were elevated, and followed by a transient but marked hyperinsulinemia at 4 hours after treatment. A single dose of recombinant murine IL-1 in mice was also associated with a 2- to 9-fold increase in the levels of insulin in the pancreas and plasma at 4 hours after treatment. During the period of observation after the administration of P. acnes, plasma glucose levels in treated mice were significantly less than in parallel controls. Mild hypoglycemia was observed at 7 to 10 days posttreatment. Although circulating IL-1-like activity could not be detected in plasma 1 to 10 days after P. acnes treatment, this activity was measured in activated peritoneal and liver M phi. IL-1-like activity (specific activity: 276 units/mg protein) was detected in plasma, after it was chromatographed on a Sephadex G-150 column to remove proteins with higher molecular weight. Peritoneal and liver M phi from P. acnes mice were also able to elaborate significant amounts of IL-1-like activity in their supernatants with or without Escherichia coli lipopolysaccharide. At the same time, total protein synthesis and insulin content in the pancreas in P. acnes mice were significantly lower than the parallel control (p less than 0.01). These results suggest that P. acnes-induced M phi activation in mice was associated with the modulation of insulin release and glucose homeostasis which may be attributed to the accumulation and release of IL-1 by activated M phi.
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PMID:Regulation of insulin and interleukin-1 release after Propionibacterium acnes-induced macrophage activation in mice. 264 66

Nonlethal endotoxemia was produced in conscious fasted rats by the intravenous (i.v.) administration of Salmonella enteritidis lipopolysaccharide (LPS) at a dose of 30 micrograms/100 g together with the typical acute-phase response of fever at 4 hr post-LPS. Also at 4 hr post-LPS both hyperinsulinemia and hyperglucagonemia were manifested, the (insulin:glucagon) (I:G) molar ratio was not different from saline control animals, and normoglycemia was maintained. The monokine interleukin-1 (IL-1), which is synthesized de novo and then released by macrophages and monocytes following LPS phagocytosis, has been implicated in the typical responses to endotoxemia. Therefore, human natural IL-1 was injected i.v. at a dose of 50 U into conscious fasted rats. IL-1-induced fever occurred at 30 min postinjection. Hyperinsulinemia equal to two times the saline control value was also present at 30 min after monokine injection, with plasma insulin levels declining to below control values by 60 min and remaining depressed for up to 12 hr. In contrast, plasma glucagon concentrations were not significantly altered at any time between 15 min and 12 hr post-IL-1. Despite IL-1-elicited hyperinsulinemia with unchanged glucagon, which elevated the I:G molar ratio, normoglycemia was maintained after monokine administration. The coincident onset of fever and hyperinsulinemia at 30 min after i.v. administration of IL-1 suggests a common mediator for both responses.
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PMID:Hyperinsulinemia elicited by interleukin-1 and nonlethal endotoxemia in rats. 266 Oct 47

The intravenous administration of bacterial endotoxin to fasted rats elicited basal portal and systemic venous hyperinsulinemia and hyperglucagonemia. Enhanced pancreatic secretion of insulin and glucagon was implied by the elevated portal venous hormonal levels. Elevated insulin and glucagon levels were present at 4 hr after a 33 micrograms/100 gm intravenous endotoxin dose despite no fluctuation of the plasma glucose concentration. The role of the liver in the pancreatic hormonal response to endotoxin was investigated by infusing lipopolysaccharide slowly into the portal vein or systemic inferior vena cava. At doses of 33 and 100 micrograms per 100 gm, endotoxin administered via the systemic route stimulated significantly greater insulin and glucagon responses than did portal administration. Furthermore, rats with acute liver injury induced by partial (67%) hepatectomy, which depressed Kupffer cell phagocytosis, did respond to the 33 micrograms per 100 gm intraportal endotoxin dose with significantly greater hyperinsulinemia and hyperglucagonemia. These data suggest that hepatic Kupffer cells normally function to remove lipopolysaccharide from the portal venous blood and that at least at low pharmacological doses the pancreatic hormonal response to endotoxin is mediated by an unknown systemic mechanism.
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PMID:Role of the liver in endotoxin-induced hyperinsulinemia and hyperglucagonemia in rats. 633 52

Increased pancreatic insulin secretion may be one of the factors associated with the insulinlike activity (ILA) of endotoxemia. While there is little doubt that the prominent hypoglycemia of endotoxicosis is often preceded by systemic hyperinsulinemia, the cause of this increased secretion and its cause-and-effect relationship to the glucose deficit is less obvious. Recently, a "misinformed B-cell" hypothesis was proposed in which it was suggested that increased glucose flux across the pancreatic B-cell early in endotoxemia might lead to a misinterpretation of the existing glycemic state, resulting in increased insulin release. This possibility was based in part on the observation that increased 6-3H-glucose-derived rates of glucose disappearance (Rd) in endotoxic Yucatan minipigs preceded the onset of systemic hyperinsulinemia. Examination herein of the chronological order of events in this group of pigs and three other groups treated with lidocaine, naloxone, or captopril reveals an increase in pancreatic insulin secretory rate most often before increases in systemic Rd. Each of the three therapies were administered as a primed continuous intravenous infusion, 1 hour after the initiation of a continuous intravenous infusion of Difco 055:B5 E. coli lipopolysaccharide at an LD67 dose of 15 micrograms/kg/hr. In those pigs receiving no therapy, lidocaine, or naloxone, significant increases in pancreatic insulin secretion recurred at 40, 40, and 60 min following the onset of endotoxemia respectively. This was followed in 20 min by the first significant increase in relative glucose disappearance rates (%Rd). Captopril-treated pigs experienced a significant increase in %Rd at 60 min, which was followed in 20 min by a significant increase in pancreatic insulin secretion. In all groups, a significant hyperinsulinemia occurred transiently at 80 min postendotoxin, followed in 20 min by the onset of significant hypoglycemia. These observations suggest that increases in %Rd and transient increases in insulin secretion may be simultaneous events at best, and that along with significant increases in absolute levels of hepatic insulin extraction (observed in all groups at 60 or 80 min postendotoxin) may indicate some local effect of insulin release on hepatic glucose.
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PMID:Hepatosplanchnic insulin kinetics in awake endotoxemic Yucatan minipigs: the "misinformed B-cell" hypothesis revisited. 639 22

We determined the role of prostanoids in mediating alterations in glucose metabolism during lipopolysaccharide (LPS)-induced (1 mg/kg; LD10) acute endotoxemia in chronically catheterized awake rats. Basal glucose turnover (Rt, infusion of [5-3H]glucose), in vivo insulin action on overall glucose utilization under normoglycemic conditions (euglycemic clamp), whole body glycolysis, and muscle glycogen synthesis were determined in four groups of rats. These groups received 1) LPS (LPS rats, n = 6); 2) saline (control rats, n = 6); 3) indomethacin and LPS (INDO and LPS rats, n = 6); or 4) saline and indomethacin (INDO control rats, n = 6). In the fasted rats, LPS induced hyperthermia, hypotension, and hyperglycemia. These changes were associated with glycogen depletion in both skeletal muscle and liver and with increased Rt. During hyperinsulinemia, whole body glucose disposal was decreased by 37% due to decreased muscle glycogen synthesis and glycogen synthase activity whereas the rate of whole body glycolysis was normal. INDO abolished hyperthermia, hypotension, and hyperglycemia but did not improve whole body insulin sensitivity, muscle glycogen synthesis, or glycogen synthase activity. These data indicate that prostanoids mediate hypotension, transient fasting hyperglycemia, and fever during LPS-induced acute endotoxemia. They do not, however, explain insulin resistance under these conditions.
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PMID:Role of prostaglandins in mediating alterations in glucose metabolism during acute endotoxemia in the rat. 789 81

Glucose dyshomeostasis is a common and life-threatening sign of endotoxic shock in the newborn. In this study, liver gluconeogenesis was evaluated in 10-day-old rats with endotoxic shock using the isolated perfused liver. Phosphoenolpyruvate carboxykinase (PEPCK) activity and PEPCK mRNA abundance were measured to confirm altered gluconeogenesis. Glucose disposal was also evaluated by a glucose tolerance test. Twenty-four-hour-fasted rats were studied to enhance gluconeogenesis and decrease glucose disposal. Rats received an intraperitoneal (IP) injection as follows: group 1 (fed-saline), 0.2 mL saline in fed rats; group 2 (fed-LPS), 0.1 mg/kg Salmonella enteritidis lipopolysaccharide (LPS) in fed rats; group 3 (fasted-saline), 0.2 mL saline in fasted rats; and group 4 (fasted-LPS), 0.1 mg/kg LPS in fasted rats. Isolated liver perfusion, determination of liver PEPCK activity and liver PEPCK mRNA abundance, and a glucose tolerance test were performed at 4 hours in fed rats and at 6 hours in fasted rats. LPS induced hypoglycemia (1.62 +/- 0.33 mmol/L, P < .05) at 6 hours in group 2 (fed-LPS), but not in group 4 (fasted-LPS). Hyperinsulinemia was not observed in either group 2 (fed-LPS) or group 4 (fasted-LPS). In group 2 (fed-LPS), liver gluconeogenesis decreased (3.0 +/- 0.3 mg/g liver, P < .01). PEPCK activity decreased from 0.65 +/- 0.07 (group 1) to 0.23 +/- 0.02 U (P < .01). PEPCK mRNA abundance also decreased from 100% +/- 10% to 40% +/- 10%. The glucose disappearance rate (t1/2) increased (P < .05) in group 2 (fed-LPS) and group 4 (fasted-LPS).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Decreased gluconeogenesis and increased glucose disposal without hyperinsulinemia in 10-day-old rats with endotoxic shock. 793 76

We characterized the mechanisms underlying acute endotoxin-induced alterations in glucose metabolism and determined the extent to which catecholamines mediate these changes. Acute endotoxemia was induced in chronically catheterized awake rats by a bolus injection of lipopolysaccharide (LPS; 1 mg/kg; LD10). Basal glucose turnover (Rt; infusion of [5-3H]glucose), in vivo insulin action on overall glucose utilization (euglycemic clamp), glycolysis, and glycogen synthesis were determined in four groups of rats. These groups received 1) LPS (LPS rats; n = 6), 2) saline (control rats; n = 6), 3) LPS and alpha beta-blockade (alpha beta-blockade and LPS rats; n = 9), or 4) saline and alpha beta-blockade (alpha beta-blockade control rats; n = 9). In the basal state, LPS induced hypotension and transient hyperglycemia. These changes were associated with glycogen depletion in both skeletal muscle and liver, and increased Rt. During hyperinsulinemia, whole body glucose disposal was 37% decreased (105 vs. 166 mumol/kg.min; P < 0.01). This whole body insulin resistance was characterized by decreased glycogen synthesis and glycogen synthase activity, but not by altered whole body glycolysis. alpha beta-Blockade abolished transient hyperglycemia, increased Rt, and accelerated basal liver glycogen depletion (45 vs. 105 mmol/kg dry, LPS and alpha beta-blockade rats vs. LPS rats; P < 0.05), but inhibited muscle glycogenolysis. alpha beta-Blockade did not reverse the insulin resistance induced by endotoxin. These data suggest that catecholamines counteract the LPS-induced increase in basal glucose turnover and stimulate muscle glycogenolysis during acute endotoxemia. These effects might explain the better preservation of hepatic glycogen in the absence than in the presence of alpha beta-blockade and serve as a defense mechanism against hypoglycemia. Catecholamines do not seem to be the immediate causes of insulin resistance during acute endotoxemia.
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PMID:Mechanisms of insulin resistance during acute endotoxemia. 815 7

Hypoglycemia occurs without hyperinsulinemia in suckling rats with endotoxic shock. However, tissue glucose uptake during endotoxic shock is not well known in the newborn. GLUT1 is insulin insensitive and is the predominant glucose transporter in 10 day old rats. In the adult with endotoxic shock, noninsulin-mediated glucose uptake and GLUT1 gene expression increase. Therefore, we hypothesized that tissue glucose uptake and GLUT1 mRNA abundance increased in 10 day old rats with endotoxic shock. The present study showed that whole body glucose disposal increased 3 h after a Salmonella enteritidis lipopolysaccharide injection (LD90 at 72 h). Plasma insulin concentration was not altered. Tissue glucose uptake increased in liver (2.4-fold) and fat (2.6-fold). However, changes of GLUT1 protein concentration were not detected in liver. GLUT1 mRNA abundance increased in liver (9-fold) and fat (4-fold). GLUT1 mRNA abundance but not glucose uptake increased in muscle. Neither glucose uptake or GLUT1 mRNA abundance was altered in brain. The mRNA abundance of tissue-specific glucose transporters (GLUT2 and GLUT4) was not altered. Thus, tissue glucose uptake and GLUT1 mRNA abundance increased without hyperinsulinemia during endotoxic shock in 10 day old rats.
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PMID:Tissue glucose transport and glucose transporters in suckling rats with endotoxic shock. 890 42


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