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)

Glomerular hyperfiltration induced by various stimuli (protein ingestion, amino-acid infusion, glucagon infusion, diabetes mellitus) is postulated to be associated with increased secretion by the liver of a hormone that increases glomerular filtration rate. In severe liver failure deficient secretion of this hormone is presumed to cause or contribute to the development of the hepatorenal syndrome. There is evidence that increased hepatic uptake of aminoacids is a factor triggering secretion of this hormone. The hypothesis, which is based on earlier published studies in laboratory animals and in man, accords well with clinical observations. This hypothesis may explain how glomeruli respond to metabolic stimuli and raises the possibility of therapeutic intervention in the glomerular hyperfiltration of diabetes and chronic renal failure.
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PMID:Glomerular hyperfiltration after protein ingestion, during glucagon infusion, and in insulin-dependent diabetes is induced by a liver hormone: deficient production of this hormone in hepatic failure causes hepatorenal syndrome. 614 38

Since glucagon and insulin (G/I) have been suggested to be hepatotrophic substances, the effect of G/I infusion on the ability to excrete water and sodium was tested in seven patients with cirrhosis and ascites (decompensated group), and compared with that in seven cirrhotics without ascites (compensated group). A constant infusion of 1 U glucagon and 10 U regular insulin over 2 hours daily for 14 days resulted in a significant improvement of prothrombin time in the decompensated group. Concomitantly, an increase in urine volume (62%, p less than 0.02) and a tendency toward an increase in urinary sodium excretion (68%, 0.05 less than p less than 0.1) were observed only in the decompensated group after the G/I infusion. In addition, these were associated with increases in creatinine clearance and osmotic clearance. These results suggest that glucagon and insulin merit further study in hepatorenal syndrome cases.
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PMID:Effect of simultaneous administration of glucagon and insulin on renal function in patients with liver cirrhosis and ascites. 637 77

In man and experimental animals, portal hypertension with portal-venous collaterals, is associated with a hyperdynamic circulation, caused by peripheral vasodilatation, mainly in the splanchnic bed. This peripheral vasodilatation is clinically important, since it is thought to be responsible for the pathogenesis of complications of portal hypertension such as ascites, the hepatorenal syndrome and portal hypertensive gastropathy and colopathy. Many cirrhotic patients may not die primarily because of their hepatic dysfunction, but rather because of the consequences of the circulatory abnormalities which are secondary to the liver disease. Circulating hormonal vasodilators from intestinal origin such as glucagon, insufficiently cleared by the liver, are only partly responsible for these changes. Recent experimental data point to a role for an increased production of the locally acting potent vasodilator nitric oxide in the vascular wall, in the pathogenesis of the hyperdynamic circulation. Furthermore, nitric oxide seems to play an important role in the development of portal-venous collaterals. Modulation of the nitric oxide production might offer therapeutic options for the treatment of portal hypertension and its complications.
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PMID:Haemodynamic changes in portal hypertension: new insights in the pathogenesis and clinical implications. 805 7

The existence of a hepatorenal link is suggested by several pathophysiological observations (indirect actions of glucagon on the kidney, hepatorenal syndrome), but the nature of this link remains unidentified. We propose that extracellular circulating cyclic AMP could be this link. Cyclic AMP (cAMP) is the intracellular second messenger of glucagon (G) action in the liver, and this organ is known to release cAMP in the blood in relatively large amounts after G administration. On the other hand, the proximal tubule (mainly the pars recta) is known to take up cAMP through the organic acid transport system. We observed that the glucagon-induced rise in phosphate excretion, which requires supraphysiologic concentration of G, was significantly correlated with the simultaneous rise in plasma cAMP and could be mimiked by i.v. infusion of cAMP alone. Moreover, we showed that a significant hyperfiltration (similar to that induced by supraphysiologic G) can be observed if cAMP (mimicking G-induced hepatic release) is coinfused with a much lower, physiologic, amount of G. Taken together, these observations suggest that: (1) cAMP is a hepatorenal link and that plasma cAMP permanently influences the intensity of reabsorption in the pars recta of the proximal tubule; and (2) that cAMP participates, in conjunction with G, to control GFR. Insulin is known to exert an inhibitory influence on G-induced cAMP release by the liver and will thus weaken the indirect (cAMP-mediated) influence of G on renal function. This "pancreato-hepatorenal cascade" may explain the natriuretic effects of G and antinatriuretic effects of insulin, and probably contributes to disturbances observed in some pathophysiological situations such as the edema of liver cirrhosis or hyperfiltration of diabetes.
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PMID:Plasma cAMP: a hepatorenal link influencing proximal reabsorption and renal hemodynamics? 918 5

The aim of the study was to verify the effects of the administration of an inhibitor of the release of endogenous vasodilators together with a vasoconstrictor agent in patients with hepatorenal syndrome (HRS). This new medical perspective was compared with a traditional medical approach for HRS, such as the infusion of nonpressor doses of dopamine to produce renal vasodilation. Thirteen patients with type 1 HRS were enrolled in the study. Five of them were treated with the oral administration of midodrine and the parenteral administration of octreotide. In addition, the patients received 50 to 100 mL of 20% human albumin solution daily for 20 days. Midodrine and octreotide were dosed to obtain a stable increase of at least 15 mm Hg of mean arterial pressure. Eight patients were treated with the intravenous administration of nonpressor doses of dopamine (2-4 micrograms/kg/min) and the same daily amount of albumin. After 20 days of treatment with midodrine and octreotide, an impressive improvement in renal plasma flow (RPF), glomerular filtration rate, and urinary sodium excretion was observed in patients. This was accompanied by a significant reduction in plasma renin activity, plasma vasopressin, and plasma glucagon. No side effects were observed. Three patients were discharged from the hospital. One of them successfully underwent liver transplantation. One of the two remaining patients is still alive after 472 days with a preserved renal function, and the other died from terminal liver failure after 76 days. One of the two patients who were not discharged from the hospital successfully underwent liver transplantation, and the other died from pneumonia after 29 days. Seven out of eight patients who were treated with dopamine experienced a progressive deterioration in renal function and died during the first 12 days. Only one patient recovered renal function and underwent liver transplantation. In conclusion, the long-term administration of midodrine and octreotide seems to be an effective and safe treatment of type 1 HRS in patients with cirrhosis.
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PMID:Reversal of type 1 hepatorenal syndrome with the administration of midodrine and octreotide. 1034 9

Glucagon binding to hepatocytes has been known for a long time to not only stimulate intracellular cAMP accumulation but also, intriguingly, induce a significant release of liver-borne cAMP in the blood. Recent experiments have shown that the well-documented but ill-understood natriuretic and phosphaturic actions of glucagon are actually mediated by this extracellular cAMP, which inhibits the reabsorption of sodium and phosphate in the renal proximal tubule. The existence of this "pancreato-hepatorenal cascade" indicates that proximal tubular reabsorption is permanently influenced by extracellular cAMP, the concentration of which is most probably largely dependent on the insulin-to-glucagon ratio. The possibility that renal cAMP receptors may be involved in this process is supported by the fact that cAMP has been shown to bind to brush-border membrane vesicles. In other cell types (i.e., adipocytes, erythrocytes, glial cells, cardiomyocytes), cAMP eggress and/or cAMP binding have also been shown to occur, suggesting additional paracrine effects of this nucleotide. Although not yet identified in mammals, cAMP receptors (cARs) are already well characterized in lower eukaryotes. The amoeba Dictyostelium discoideum expresses four different cARs during its development into a multicellular organism. cARs belong to the superfamily of seven transmembrane domain G protein-coupled receptors and exhibit a modest homology with the secretin receptor family (which includes PTH receptors). However, the existence of specific cAMP receptors in mammals remains to be demonstrated. Disturbances in the pancreato-hepatorenal cascade provide an adequate pathophysiological understanding of several unexplained observations, including the association of hyperinsulinemia and hypertension, the hepatorenal syndrome, and the hyperfiltration of diabetes mellitus. The observations reviewed in this paper show that cAMP should no longer be regarded only as an intracellular second messenger but also as a first messenger responsible for coordinated hepatorenal functions, and possibly for paracrine regulations in several other tissues.
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PMID:Extracellular cAMP inhibits proximal reabsorption: are plasma membrane cAMP receptors involved? 1183 18

The hepatorenal syndrome (HRS) is related to vasoconstriction of the renal cortex induced by systemic hypovolemia that follows splanchnic vasodilatation as the primary event in the cascade of hemodynamic changes associated with portal hypertension. We evaluated the effects of octreotide, a splanchnic vasoconstrictor, on HRS in cirrhotic patients. We compared the effects of octreotide infusion (50 microg/h) to placebo using a randomized, double-blind, cross-over design over 2, 4-day periods. Nineteen patients were included, and 14 patients could complete the 2 phases of the study (group 1: placebo first; n = 8 and group 2: octreotide first; n = 6) The end point of the study was to evaluate improvement in renal function as defined by a 20% decrease in serum creatinine value after a 4-day treatment as compared with baseline. In all the patients, a normal central venous pressure was maintained by daily intravenous administration of 2 units of albumin. The 2 groups were similar with regard to demographic data and liver and kidney function parameters at baseline. Improvement in renal function was observed in 2 patients after the placebo and 1 patient after octreotide infusion in group 1 and in 2 patients after octreotide infusion and 1 patient after placebo in group 2 (P = not significant). In addition, treatment with octreotide infusion did not result in significant changes in creatinine clearance, daily urinary sodium, plasma renin activity, plasma aldosterone and glucagon levels, or renal and mesenteric artery resistance indices as measured by Doppler ultrasonography. In conclusion, the present study demonstrates that, under our experimental conditions, octreotide infusion combined with albumin is not effective for the treatment of HRS in cirrhotic patients.
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PMID:Octreotide in hepatorenal syndrome: a randomized, double-blind, placebo-controlled, crossover study. 1283 7