Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The prominent protein phosphatases involved in liver glycogen metabolism are the AMD (ATP, Mg-dependent, type-1) and PCS (polycation-stimulated, type-2A) phosphatases. The glycogen synthase phosphatase activity, measured from the rate of activation of liver glycogen synthase, is virtually accounted for by AMD phosphatases; the bulk of the activity belongs to the glycogen-bound protein phosphatase G and a small part is present in the cytosol. The major part of the phosphorylase phosphatase activity present in the post-mitochondrial supernatant is shared by protein phosphatase G and cytosolic enzymes, and a minor part belongs to a microsomal AMD phosphatase. In the liver cytosol, the phosphorylase phosphatase activity is about equally distributed between AMD and PCS phosphatases. Studies in vivo as well as on isolated, perfused livers have shown that glucagon (which raises the level of cyclic AMP) as well as vasopressin (which increases the cytosolic Ca2+ concentration) decrease the phosphorylase phosphatase activity in liver extract or cytosol (filtered through Sephadex G-25) by about 25% within a few minutes. These effects were not additive, and the activity of glycogen synthase phosphatase was not affected. Conversely, insulin as well as glucose increased both phosphatase activities by about 25%, and these effects were additive. Vanadate mimicked the effect of insulin on the perfused liver. All the activity changes were only observed when the assays were performed at high tissue concentration. Upon subcellular fractionation all the effects were well expressed in the cytosol, but not in the particulate fraction (glycogen and microsomes). However, quantitatively the hormonal responses were largely lost during the fractionation procedure; they could be restored by recombination of the liver cytosol from a hormone-treated rat with the particulate fraction from either a treated or an untreated animal. It appears that the effects of glucagon, insulin and glucose are mediated by cytosolic, transferable effectors of the Vmax of protein phosphatases. These effectors are eluted in the void volume of a Sephadex G-25 column. Rats of the gsd/gsd strain, which have a genetic deficiency of hepatic phosphorylase kinase, responded to an injection of insulin plus glucose with a normal increase in the cytosolic phosphorylase phosphatase activity. In contrast, they failed to respond to glucagon as well as vasopressin. A transient 80% inhibition of the phosphorylase phosphatase activity could be induced in vitro in a concentrate liver cytosol from Wistar rats upon addition of MgATP.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Short-term hormonal control of protein phosphatases involved in hepatic glycogen metabolism. 216 98

The management of both acute and recurrent variceal bleeding continues to be a significant challenge to the clinician. The cause and pathogenesis of portal hypertension has been described. Alcoholic cirrhosis is the most common cause of intrahepatic sinusoidal and postsinusoidal obstruction in the United States. Long term survival depends on rapid institution of an established protocol of surgical management for variceal hemorrhage. A patient who presents with variceal bleeding must be rapidly stabilized with fluid resuscitation, and specific measures, such as the use of vasopressin and balloon tamponade, must be instituted to control hemorrhage so that endoscopy can be used to establish the diagnosis. Sclerotherapy achieves a high rate of success in the acute situation, but if hemorrhage cannot be controlled, percutaneous transhepatic embolization or emergent shunting must be performed, depending on the condition of the patient. Angiography, prior to surgical treatment, is necessary to define venous anatomy and determine portal hemodynamics, both of which provide information vital in choosing the type of shunt. If bleeding is massive and the patient is unstable, H-grafts are most appropriate, for they are technically easier and give excellent short term results. In a stable Child's A or B patient with minor ascites as well as suitable anatomy and hepatopedal flow, DSRS is the procedure of choice because it produces the smallest degree of HE postoperatively and increases the survival rate for nonalcoholics. If this is not feasible or if the surgeon lacks the technical expertise to perform DSRS, PCS is the logical alternative. In view of the data from the series observed in the United States, ablative procedures cannot be recommended at the present for the treatment of variceal bleeding. In the Child's C poor-risk patient, the operative mortality rate is prohibitive, and only nonsurgical means should be used to establish control of bleeding. In the elective situation, the surgical options change. The efficacy of ES as a definitive procedure to control recurrent variceal bleeding is unproved, and rebleeding can be significant; therefore, it cannot be recommended. H-grafts have a prohibitively high rate of long term thrombosis and are also not recommended, and the Linton or proximal splenorenal shunt offers no advantages over conventional portacaval shunting. Moreover, arterialization of the hepatic stumps of the portal vein does not prevent hepatic encephalopathy or alter the survival rate. Both PCS and DSRS prevent rebleeding, yet neither alters the survival rate for alcoholic patients.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Portal hypertension. 240 26