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)

Cell-to-cell communication via gap junctions has been proposed to be involved in the metabolic actions of sympathetic liver nerves in the rat. The effects of hepatic nerve stimulation and noradrenaline-, PGF2 alpha- and glucagon infusion on glucose metabolism and perfusion flow were studied in perfused rat liver in the absence and presence of the gap junctional inhibitors, heptanol, carbenoxolone and (4 beta)phorbol 12-myristate 13-acetate (4 beta PMA). (i) Stimulation of the hepatic nerve plexus increased glucose output, decreased flow and caused an overflow of noradrenaline into the hepatic vein. (ii) Heptanol completely inhibited not only the nerve stimulation-dependent metabolic and hemodynamic alterations but also the noradrenaline overflow. Thus the heptanol-dependent inhibitions were caused primarily by a strong impairment of transmitter release. (iii) Carbenoxolone inhibited the effects of neurostimulation on glucose metabolism partially by about 50%, whereas it left perfusion flow and noradrenaline overflow essentially unaltered. (iv) 4 beta PMA reduced the nerve stimulation-dependent enhancement of glucose release by about 80% but the noradrenaline-dependent increase in glucose output only by about 30%; the increase in glucose release by PGF2 alpha and by glucagon remained essentially unaltered. 4 beta PMA reduced the nerve stimulation-dependent decrease in portal flow by about 35% but did not affect the noradrenaline-and PGF2 alpha-elicited alterations, nor did it alter noradrenaline overflow. The results allow the conclusion that gap junctional communication plays a major role in the regulation of hepatic carbohydrate metabolism by sympathetic liver nerves, but not by circulating noradrenaline, PGF2 alpha or glucagon.
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PMID:Signal propagation via gap junctions, a key step in the regulation of liver metabolism by the sympathetic hepatic nerves. 157 64

11 beta-Hydroxysteroid dehydrogenase type 1 (11 beta-HSD1) regenerates cortisol from inactive cortisone in liver and adipose tissue. Inhibition of 11 beta-HSD1 offers a novel potential therapy to lower intracellular cortisol concentrations and thereby enhance insulin sensitivity and hepatic lipid catabolism in type 2 diabetes, obesity, and hyperlipidemia. We evaluated this approach using the nonselective 11 beta-HSD inhibitor, carbenoxolone, in healthy men and lean male patients with type 2 diabetes. Six diet-controlled nonobese diabetic patients with hemoglobin A(1c) less than 8%, and six matched controls participated in a double-blind, cross-over comparison of carbenoxolone (100 mg every 8 h, orally, for 7 d) and placebo. They were admitted overnight for infusions of insulin (as required to maintain arterialized plasma glucose of 5.0 mM) and [13C6]glucose. Glucose kinetics were measured in the fasted state from 0700-0730 h, during a 3-h euglycemic hyperinsulinemic clamp (including somatostatin infusion and replacement of physiological GH and glucagon levels), and during a 2-h euglycemic hyperinsulinemic clamp with a 4-fold increase in glucagon levels. Data are the mean +/- SEM. Carbenoxolone had the expected effects of raising blood pressure and lowering plasma potassium. Carbenoxolone reduced total cholesterol in healthy subjects (5.25 +/- 0.34 vs. 4.78 +/- 0.40 mM; P < 0.01), but had no effect on other serum lipids or on cholesterol in diabetic patients. Carbenoxolone did not affect the rate of glucose disposal or the suppression of free fatty acids during hyperinsulinemia. However, carbenoxolone reduced the glucose production rate during hyperglucagonemia in diabetic patients (1.90 +/- 0.2 vs. 1.53 +/- 0.3 mg/kg x min; P < 0.05). This was attributable to reduced glycogenolysis (1.31 +/- 0.2 vs. 1.01 +/- 0.2 mg/kg x min; P < 0.005) rather than altered gluconeogenesis. These observations reinforce the potential metabolic benefits of inhibiting 11 beta-HSD1 in the liver of patients with type 2 diabetes. Further studies in obesity and hyperlipidemia are now warranted. However, clinically useful therapeutic effects will probably require selective 11 beta-HSD1 inhibitors that lower intraadipose cortisol levels and enhance peripheral glucose uptake.
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PMID:Effects of the 11 beta-hydroxysteroid dehydrogenase inhibitor carbenoxolone on insulin sensitivity in men with type 2 diabetes. 1251 67