Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients who have liver diseases are susceptible to septic shock. Galactosamine induces liver damage and increases endotoxin-sensitivity. Hydrazine stimulates pituitary-adrenal axis and decreases mortality in galactosamine-sensitized endotoxic shock in the adult. However, as pituitary-adrenal function in the newborn is immature, the effects of hydrazine on galactosamine-sensitized endotoxic shock in the newborn remained unclear. In the present study, galactosamine-sensitized endotoxic shock was induced and treated with hydrazine in ten-day-old rats. Galactosamine (600 mg/kg) plus Salmonella enteritidis lipopolysaccharide (LPS; 0.01 mg/kg) induced hypoglycemia, lactacidemia and resulted in high mortality. Hydrazine at the dose of 20, 50 or 80 mg/kg did not alter the hypoglycemia, lactacidemia or morality. Dexamethasone ameliorated the hypoglycemia and lactacidemia (p < 0.05) and decreased the morality (p < 0.05). The lack of beneficial effects of hydrazine in galactosamine-sensitized endotoxic shock in ten-day-old rats may be related to immature pituitary-adrenal function and suppression of gluconeogenesis by hydrazine.
Res Commun Mol Pathol Pharmacol 1998 Feb
PMID:Effects of hydrazine sulfate on galactosamine-sensitized endotoxic shock in ten-day-old rats. 958 97

The insulin receptor kinase (IRK) is a tyrosine kinase whose activation, subsequent to insulin binding, is essential for insulin-signalling in target tissues. Insulin binding to its cell surface receptor is rapidly followed by internalization of insulin-IRK complexes into the endosomal apparatus (EN) of the cell. Internalization of insulin into target organs, especially liver, is implicated in effecting insulin clearance from the circulation. Internalization mediates IRK downregulation and hence attenuation of insulin sensitivity although most internalized IRKs readily recycle to the plasma membrane at physiological levels of insulin. A role for internalization in insulin signalling is indicated by the accumulation of activated IRKs in ENs. Furthermore, the maximal level of IRK activation has been shown to exceed that attained at the cell surface. Using an in vivo rat liver model in which endosomal IRKs are exclusively activated has revealed that IRKs at this intracellular locus are able by themselves to promote IRS-1 tyrosine phosphorylation and induce hypoglycemia. Furthermore, studies with isolated rat adipocytes reveal the EN to be the principle site of insulin-stimulated IRS-1 tyrosine phosphorylation and associated PI3K activation. Key steps in the termination of the insulin signal are also operative in ENs. Thus, an endosomal acidic insulinase has been identified which limits the extent of IRK activation. Furthermore, IRK dephosphorylation is effected in ENs by an intimately associated phosphotyrosine phosphatase(s) which, in rat liver, appears to regulate IRK activity in both a positive and negative fashion. Thus, insulin-mediated internalization of IRKs into ENs plays a crucial role in effecting and regulating signal transduction in addition to modulating the levels of circulating insulin and the cellular concentration of IRK in target tissues.
Mol Cell Biochem 1998 May
PMID:Insulin receptor internalization and signalling. 960 14

Familial hyperinsulinism (HI) is a disorder characterized by dysregulation of insulin secretion and profound hypoglycemia. Mutations in both the Kir6.2 and sulfonylurea receptor (SUR1) genes have been associated with the autosomal recessive form of this disorder. In this study, the spectrum and frequency of SUR1 mutations in HI and their significance to clinical manifestations of the disease were investigated by screening 45 HI probands of various ethnic origins for mutations in the SUR1 gene. Single-strand conformation polymorphism (SSCP) and nucleotide sequence analyses of genomic DNA revealed a total of 17 novel and three previously described mutations in SUR1 . The novel mutations comprised one nonsense and 10 missense mutations, two deletions, three mutations in consensus splice-site sequences and an in-frame insertion of six nucleotides. One mutation occurred in the first nucleotide binding domain (NBF-1) of the SUR1 molecule and another eight mutations were located in the second nucleotide binding domain (NBF-2), including two at highly conserved amino acid residues within the Walker A sequence motif. The majority of the remaining mutations was distributed throughout the three putative transmembrane domains of the SUR1 protein. With the exception of the 3993-9G-->A mutation, which was detected on 4.5% (4/88) disease chromosomes, allelic frequencies for the identified mutations varied between 1.1 and 2.3% for HI chromosomes, indicating that each mutation was rare within the patient cohort. The clinical manifestations of HI in those patients homozygous for mutations in the SUR1 gene are described. In contrast with the allelic homogeneity of HI previously described in Ashkenazi Jewish patients, these findings suggest that a large degree of allelic heterogeneity at the SUR1 locus exists in non-Ashkenazi HI patients. These data have important implications for genetic counseling and prenatal diagnosis of HI, and also provide a basis to further elucidate the molecular mechanisms underlying the pathophysiology of this disease.
Hum Mol Genet 1998 Jul
PMID:Genetic heterogeneity in familial hyperinsulinism. 961 69

Hypoxia elicits a number of compensatory responses in animals, including behavioral hypothermia. The hypothesis that hypoglycemia induces hypothermia in the bullfrog Rana catesbeiana was tested and that this behavioral response would be beneficial. Frogs equipped with a temperature probe were tested in a thermal gradient (10-40 degrees C). Insulin (15 IU kg-1) caused significant reduction of body temperature, from 25.0 to 17.8 degrees C. A non-metabolizable glucose analogue, 2-deoxy-D-glucose (2-DG, 50 mg kg-1), which blocks intracellular glucose utilization, was also injected and caused a similar drop in body temperature, despite an increase in plasma glucose levels. To assess the possible benefits of hypoglycemia-induced hypothermia, the effects of insulin and 2-DG injections were measured on plasma glucose concentration and on oxygen consumption of frogs equilibrated at 10, 20 and 30 degrees C. The plasma glucose was elevated at higher temperatures and so was oxygen consumption. The insulin caused a significant reduction of plasma glucose concentration (about 1.22 muMol ml-1) whereas 2-DG caused a significant increase (about 0.70 muMol ml-1) at 30 degrees C. Both drugs caused a reduction of oxygen consumption (approximately 0.388 and 0.382 ml min-1 kg at 30 degrees C after insulin and 2-DG injection, respectively). No effect of either insulin or 2-DG was observed when the animals were equilibrated at 10 degrees C. In conclusion, hypothermia may be a beneficial response to hypoglycemia in frogs.
Comp Biochem Physiol A Mol Integr Physiol 1998 Apr
PMID:Physiological significance of behavioral hypothermia in hypoglycemic frogs (Rana catesbeiana). 977 88

Acute immunoneutralization of circulating leptin, with an anti-leptin antibody, significantly reduced rectal temperature at 30 min and 75 min post-injection in overnight fasted and at 30 min in overnight fed mice, while no effects in metabolic and ponderal indicators were observed after antibody administration for 22 days. Furthermore, hyperinsulinemia and hypoglycemia were induced by passive immunization against leptin, being both influenced by the post-prandrial status. These experiments confirm through an indirect approach that leptin is involved in energy, but also in glucose homeostasis.
Int J Mol Med 1998 Dec
PMID:Induction of hypothermia, hypoglycemia and hyperinsulinemia after acute leptin immunoneutralization in overnight fasted mice. 985 Jul 36

The treatment of patients with type 1 diabetes mellitus has to focus on short-term and long-term risks of the disease which means to avoid hyperglycemic or hypoglycemic coma as well as late complications. As we know from the DCCT study metabolic control substantially lowers the risk for retinopathy, nephropathy and neuropathy. We also know, that keeping the blood glucose in a nearly normal range inevitably is connected with a marked increase of severe hypoglycemia, an event which occurs more frequently when normoglycemia has been reached and the further slow decline of blood glucose is not recognized by the patient (autonomous neuropathy, hypoglycemia unawareness of other origin, long duration of diabetes etc.). Furthermore, counterregulatory hormones as glucagon and epinephrine may be lacking due to diminished or even lost alpha cells within the islets and as recently observed due to fibrosis of the adrenal medulla in long-term diabetes. The consequences of severe hypoglycemia are manifold: in the actual situation of unconsciousness the risk of heavy injuries and as long-term consequences irreversible brain damage may occur. Finally, the effort of the patient to reach normoglycemia includes the burden of an intensive blood glucose self-control day by day. This broad scenario of all the achievements and of all the problems connected with an intensified insulin treatment has to be regarded when the indication for an islet transplant will be discussed. From our point of view as clinicians it seems adequate not to give definite recommendations but to express our considerations for islet transplantation in patients with type 1 diabetes mellitus with the following list (table 1). It must be clearly stated, that at present transplantation of isolated islets by no means can serve as a treatment for a larger number of patients and this may hold through also for the foreseeable future. In this context, also the many contraindications should be summarized (table 2). Consequently we have to deal with several questions and problems which can be subdivided into those regarding the possible benefit for the patients from an islet graft (full success = insulin independence, partial success = lower exogenous insulin requirement due to additional endogenous insulin, measured by C-peptide levels, more stable glucose metabolism) and those regarding possible side effects (primary risk of implantation, threat for rejection of the primarily transplanted kidney). Furthermore, one may ask for risks when islets are transplanted alone (ITA). We therefore will address the following areas: 1. Simultaneous islet and kidney transplants 2. Islet transplants after kidney transplantation alone (IAK) 3. Islet transplantation after pancreas transplantation failure (P-failure) 4. Defect hypoglycemia counterregulation--life threatening hypoglycemia unawareness as indication for islet transplantation? 5. Autonomous cardiac neuropathy as indication for islet transplantation? 6. Significant clinical problems with exogenous insulin therapy as indication for islet transplantation?
J Mol Med (Berl) 1999 Jan
PMID:Indications for clinical islet transplantation today and in the forseeable future--the diabetologist's point of view. 993 Sep 51

The participation of hepatic glycogenolysis and gluconeogenesis to the glycemic changes promoted by exercise was investigated. For this purpose, we employed swimming rats (2.5% body weight extra load attached to the tail, at 24 degrees C) using a favorable condition to measure hepatic glycogenolysis (fed rats) and a favorable condition to measure hepatic gluconeogenesis (fasted rats). This experimental approach permits us to compare the contribution of hepatic glycogenolysis and gluconeogenesis to glucose changes for a specific schedule of exercise. The animals were investigated at rest, after 5 minutes of swimming and after swimming to exhaustion. Our results show that hepatic glycogen has a crucial role to determine hyperglycemia during exercise. In contrast, hypoglycemia developed during exercise when glycogen was depleted. However, the ability of the liver to produce glucose from L-lactate, glycerol and L-glutamine was increased during exercise. Taken together, these findings suggest that the hepatic capacity to produce glucose from gluconeogenic substrates (except for L-alanine) was increased when hepatic glycogen stores were depleted. Thus, the increased capacity to produce glucose shown by livers from exercising rats must to be an important metabolic adaptation to protect against severe hypoglycemia.
Res Commun Mol Pathol Pharmacol 1998 Nov
PMID:Changes in glycemia induced by exercise in rats: contribution of hepatic glycogenolysis and gluconeogenesis. 1010 May 3

Considerable evidence suggests that oxidative stress plays an important role in tissue damage associated with hypoglycemia and other metabolic disorders. The altered brain neurotransmitters metabolism, cerebral electrolyte contents, and impaired blood-brain barrier function may contribute to CNS dysfunction in hypoglycemia. The present study elucidates the effect of starvation and insulin-induced hypoglycemia on the free radical scavanger system--reduced glutathione (GSH) content, glutathione S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR), gamma-glutamyl transpeptidase (gamma-GTP), gamma-glutamyl cystein synthetase (gamma-GCS), catalase and superoxide dismutase (SOD), and mitochondrial electron transport chain (ETC) complexes I-IV from three different regions of rat brain, namely cerebral hemispheres (CH), cerebellum (CB), and brainstem (BS). Peripheral organs, such as liver and kidney, were also studied. Significant changes in these enzymic activities were observed. The analysis of such alterations is important in ultimately determining the basis of neuronal dysfunction during metabolic stress conditions, such as hypoglycemia, and also defining the nature of these changes may help to develop therapeutic means to cure metabolically stressed tissues.
Mol Chem Neuropathol
PMID:Effect of starvation and insulin-induced hypoglycemia on oxidative stress scavenger system and electron transport chain complexes from rat brain, liver, and kidney. 1032 15

The mechanisms responsible for the glycemic changes associated with endotoxic shock are not fully understood, but are known to involve the ability of the liver to produce glucose. The purpose of the present study was to determine whether endotoxin (LPS) influences the expression and activity of glucose-6-phosphatase (Glu-6-Pase) during the early hyperglycemic phase and the later hypoglycemic phase. Rats were injected with a relatively large dose of LPS (20 mg/kg) or saline (control), and sacrificed at 1 or 5 h post-injection. Both the plasma glucose concentration and glucose production were elevated 1 h post-LPS (2-fold) and both decreased at 5 h postinjection (50%). Compared to time-matched control values, hepatic glucose-6-phosphate and fructose-6-phosphate levels were significantly decreased at both 1 and 5 h. Hepatic Glu-6-Pase activity and mRNA levels were moderately increased, 1 h after injection of LPS. At 5 h, an 88% decrease in mRNA abundance for Glu-6-Pase was associated with a 30% decrease in activity of this enzyme. Plasma insulin concentrations were not different 1 h after LPS and were elevated 2-fold from control values at 5 h. Circulating levels of glucagon and corticosterone were elevated at both time points following LPS. Our data indicate that the LPS-induced hypoglycemia and reduction in hepatic glucose production were accompanied by a depression in Glu-6-Pase activity and gene expression.
Mol Cell Biochem 1999 Jun
PMID:Endotoxin-induced alterations in hepatic glucose-6-phosphatase activity and gene expression. 1044 5

Numerous studies have focused on the metabolic contributions of glucose and other substrates in isolated tissue preparations by examining the effects of eliminating glucose from the physiologic perfusate or bath solution. To date, however, an effective method of glucose removal from the blood supply to selected tissue in the whole animal model has not been available. We have developed a method for blood glucose removal by continuous flow dialysis. This method was used to generate isolated coronary hypoglycemia for an investigation of myocardial metabolic substrate selection during hypoperfusion in open-chest, anesthetized dogs. Arterial blood was passed through the dialysis system against an isotonic and physiologic dialysate solution prior to controlled coronary perfusion. During normal perfusion pressure (100 mmHg), with a coronary blood flow of 32+/-4 ml/min, arterial blood glucose was reduced from 3.26+/-0.31 to 0.54+/-0.14 mM. When blood flow was reduced to 12+/-3 ml/min with lower perfusion pressure (40 mmHg), dialysis reduced arterial glucose from 3.53+/-0.36 to 0.15+/-0.03 mM. We conclude that this is an effective method for producing regional hypoglycemia.
Mol Cell Biochem 1999 Oct
PMID:A method for producing regional hypoglycemia in blood perfused tissue. 1056 98


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