Increased expression of cyclooxygenase-1 and -2 in the diabetic rat renal medulla

2003 ◽  
Vol 285 (6) ◽  
pp. F1068-F1077 ◽  
Author(s):  
Rania Nasrallah ◽  
Anne Landry ◽  
Sonia Singh ◽  
Monika Sklepowicz ◽  
Richard L. Hébert
Keyword(s):  
Collecting Duct ◽  
Renal Medulla ◽  
Immunohistochemical Analysis ◽  
Diabetic Rats ◽  
Diabetic Rat ◽  
Fourfold Increase ◽  
Protein Levels ◽  
Cyclooxygenase 1 ◽  
Streptozotocin Diabetic Rats ◽  
Medullary Collecting Duct

Alterations in renal prostaglandins (PGs) may contribute to some of the renal manifestations in diabetes leading to nephropathy. PG production is dependent on the activity of cyclooxygenases (COX-1 AND -2) and PG synthases. Our present study investigated levels of these enzymes in streptozotocin-diabetic rats at 2, 4, 6, and 8 wk of diabetes. Immunohistochemical analysis revealed an increase in COX signal in the inner and outer medulla of diabetic rats. This was confirmed by Western blotting, showing up to a fourfold increase in both COX isoforms at 4–6 wk of diabetes. Also, Western blot analysis revealed a sixfold increase in PGE2 synthase expression in the outer medullary region of 6-wk diabetic rats but no difference in the inner medulla. In cultured rat inner medullary collecting duct (IMCD), levels of COX were increased two- to threefold in cells exposed for 4 days to 37.5 mM glucose compared with control of 17.5 mM. While no change in PGE2 synthase levels was noted, PGE2 synthesis was increased. Furthermore, levels of EP1 and EP4 mRNA were increased, as well as a twofold increase in EP4 protein levels. Future studies will determine which COX isoform is contributing to the majority of PGE2 produced in the diabetic IMCD and the significance of these findings to disturbances in IMCD function and to the progression of diabetic nephropathy.

scholarly journals Posttranslational regulation of NO synthase activity in the renal medulla of diabetic rats

2005 ◽  
Vol 288 (1) ◽  
pp. F82-F90 ◽  
Author(s):  
Dexter L. Lee ◽  
Jennifer M. Sasser ◽  
Janet L. Hobbs ◽  
Amy Boriskie ◽  
David M. Pollock ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Renal Medulla ◽  
Immunohistochemical Analysis ◽  
Diabetic Rats ◽  
No Synthase ◽  
No Production ◽  
Thick Ascending Limb ◽  
Posttranslational Regulation ◽  
Osmotic Diuresis ◽  
Protein Levels

Shear stress increases nitric oxide (NO) production by endothelial cells, inner medullary collecting duct cells, and thick ascending limb. We postulated that the osmotic diuresis accompanying type 1 diabetes is associated with increased NO synthase (NOS) activity and/or expression in the renal medulla. Diabetes was induced by injection of streptozotocin, with insulin provided to maintain moderate hyperglycemia (Hyp) or euglycemia (Eug) for 3 wk. Sham rats received vehicle treatments. A separate group of rats (Phz) received phlorizin to produce a glucose-dependent osmotic diuresis. Renal medullary NOS1 and NOS2 activities did not differ between groups, whereas NOS3 activity was significantly increased in Hyp. Neither NOS1 nor NOS3 protein levels differed significantly between groups. Reduced phosphorylation of NOS3 at Thr495 and Ser633 was evident in medullary homogenates from Hyp rats, with no difference apparent at Ser1177. Immunohistochemical analysis indicated prominent expression of pThr495NOS3 in the thick ascending limb and collecting duct of Sham and Phz rats. Hyp rats displayed staining in the collecting duct but minimal thick ascending limb staining. Immunostaining with anti-pSer1177NOS3 was evident only in the thick ascending limb, with no apparent differences between groups. In summary, glucose-dependent osmotic diuresis alone did not alter NOS activity or expression in the renal medulla. Diabetic hyperglycemia increased medullary NOS3 activity without a concomitant increase in NOS3 protein levels; however, NOS3 phosphorylation was reduced at Thr495 and Ser633. Thus changes in the phosphorylation of NOS at known regulatory sites might represent the primary mechanism underlying increased renal medullary NOS activity in diabetic hyperglycemia.

scholarly journals Oxidative Stress in Rats After 60 Days of Hypergalactosemia or Hyperglycemia

2003 ◽  
Vol 22 (6) ◽  
pp. 423-427 ◽  
Author(s):  
Mary Otsyula ◽  
Matthew S. King ◽  
Tonya G. Ketcham ◽  
Ruth A. Sanders ◽  
John B. Watkins
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Superoxide Dismutase ◽  
Glutathione Peroxidase ◽  
Insulin Treatment ◽  
Diabetic Rats ◽  
Diabetic Rat ◽  
Glutathione Disulfide ◽  
Hepatic Lipid Peroxidation ◽  
Streptozotocin Diabetic Rats

Two of the models used in current diabetes research include the hypergalactosemic rat and the hyperglucosemic, streptozotocin-induced diabetic rat. Few studies, however, have examined the concurrence of these two models regarding the effects of elevated hexoses on biomarkers of oxidative stress. This study compared the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase and the concentrations of glutathione, glutathione disulfide, and thiobarbituric acid reactants (as a measure of lipid peroxidation) in liver, kidney, and heart of Sprague-Dawley rats after 60 days of either a 50% galactose diet or insulin deficiency caused by streptozotocin injection. Most rats from both models developed bilateral cataracts. Blood glucose and glycosy-lated hemoglobin A1c concentrations were elevated in streptozotocin diabetic rats. Streptozotocin diabetic rats exhibited elevated activities of renal superoxide dismutase, cardiac catalase, and renal and cardiac glutathione peroxidase, as well as elevated hepatic lipid peroxidation. Insulin treatment of streptozotocin-induced diabetic rats normalized altered markers. In galactosemic rats, hepatic lipid peroxidation was increased whereas glutathione reductase activity was diminished. Glutathione levels in liver were decreased in diabetic rats but elevated in the galactosemic rats, whereas hepatic glutathione disulfide concentrations were decreased much more in diabetes than in galactosemia. Insulin treatment reversed/prevented all changes caused by streptozotocin-induced diabetes. Lack of concomitance in these data indicate that the 60-day galactose-fed rat is not experiencing the same oxidative stress as the streptozotocin diabetic rat, and that investigators must be cautious drawing conclusions regarding the concurrence of the effects of the two animal models on oxidative stress biomarkers.

Endothelin receptor mRNA expression in renal medulla identified by in situ RT-PCR

1995 ◽  
Vol 269 (3) ◽  
pp. F449-F457 ◽  
Author(s):  
L. H. Chow ◽  
S. Subramanian ◽  
G. J. Nuovo ◽  
F. Miller ◽  
E. P. Nord
Keyword(s):  
Mrna Expression ◽  
Collecting Duct ◽  
Renal Medulla ◽  
Receptor Subtypes ◽  
Rt Pcr ◽  
Receptor Mrna ◽  
Pcr Products ◽  
Medullary Collecting Duct ◽  
Labeled Probe

Three subtypes of endothelin (ET) receptors have been identified by cDNA cloning, namely ET-RA, ET-RB, and ET-RC. In the current study the precise cellular distribution of the ET receptor subtypes in the renal medulla was explored by detecting the corresponding polymerase chain reaction (PCR)-amplified cDNAs by in situ reverse transcription (RT)-PCR. The PCR-amplified cDNAs were detected either by direct incorporation using digoxigenin-dUTP (dig-dUTP) as a nucleotide substrate in the PCR reaction or by in situ hybridization with the dig-dUTP-labeled probe. ET-RB mRNA was detected exclusively in the epithelial cells of the inner and outer medullary collecting duct. In contrast, ET-RA message was observed primarily in interstitial cells and pericytes of the vasae rectae in the outer and inner medulla. Southern blot analysis of PCR-amplified cDNAs reverse transcribed from extracted RNA of rat renal medulla confirmed the specificity of the RT-PCR products. ET-RC mRNA was not detected. We conclude that ET-RB is the major ET receptor found in rat renal medulla and is expressed exclusively on inner medullary collecting duct cells. The pattern of ET receptor mRNA expression described suggests different physiological actions for ET on the diverse cellular structures of the renal medulla.

scholarly journals 3-oxo acid coenzyme A-transferase in normal and diabetic rat muscle

1976 ◽  
Vol 158 (2) ◽  
pp. 509-512 ◽  
Author(s):  
A Fenselau ◽  
K Wallis
Keyword(s):  
Skeletal Muscle ◽  
Coenzyme A ◽  
Substrate Inhibition ◽  
Diabetic Rats ◽  
Diabetic Rat ◽  
Functional Parameters ◽  
Rat Muscle ◽  
Coa Transferase ◽  
Normal Rat ◽  
Streptozotocin Diabetic Rats

The amounts of succinyl-CoA--3-oxo acid CoA-transferase (EC 2.8.3.5) decrease progressively in skeletal muscle in streptozotocin-diabetic rats, reaching after 10 days about 50% of the value in normal rat muscle. Electrofocusing studies indicate the occurrence of partial proteolysis of the enzyme in diabetic muscle. However, several functional parameters relating to acetoacetate utilization, including substrate inhibition, are quite similar for muscle transferase preparations from normal and diseased rats. The development of pathological ketoacidosis is discussed in the light of these observations.

scholarly journals Isolation of insulin-sensitive phosphatidylinositol-glycan from rat adipocytes. Its impaired breakdown in the streptozotocin-diabetic rat

1990 ◽  
Vol 271 (2) ◽  
pp. 427-435 ◽  
Author(s):  
S L Macaulay ◽  
R G Larkins
Keyword(s):  
Phospholipase C ◽  
Pyruvate Dehydrogenase ◽  
Cell Types ◽  
Solvent System ◽  
Diabetic Rats ◽  
Diabetic Rat ◽  
Rat Adipocytes ◽  
Impaired Insulin ◽  
Streptozotocin Diabetic Rats ◽  
Concentration Response Curve

In this study an insulin-sensitive glycophospholipid from rat adipocytes was isolated and partially characterized. A material that activated pyruvate dehydrogenase was extracted from rat adipocyte membrane supernatants. Its release was stimulated by insulin and phosphatidylinositol-specific-phospholipase C and its activity was destroyed by nitrous acid deamination. These findings suggested that insulin might stimulate breakdown of a glycophospholipid containing inositol and glucosamine, as previously reported for some other cell types [Low & Saltiel (1988) Science 239, 268-275]. A lipid that incorporated [3H]glucosamine, [3H]galactose, [3H]inositol, and [3H]myristate and whose turnover was stimulated by insulin was subsequently isolated from intact adipocytes by sequential t.l.c. using an acidic solvent system followed by a basic solvent system. The effects of insulin on turnover of the lipid in these cells were transient, with maximal effects at 1 min, and there was a typical concentration-response curve to insulin (0.07 nM-7 nM), with effects being detected over the physiological range of insulin concentrations. In contrast with studies in other cells, there was appreciable turnover of the sugar labels. The majority of the [3H]glucosamine and [3H]galactose labels were cycled through to triacylglycerol in the adipocyte. However, of that recovered in the glycophospholipid band, a major proportion (less than 40%) was recovered as the native label. Digestion of the purified molecule with phosphatidylinositol-specific phospholipase C generated a material that activated both pyruvate dehydrogenase and low-Km cyclic AMP phosphodiesterase. Impairment in insulin-stimulated breakdown of the molecule in adipocytes of streptozotocin-diabetic rats was found, consistent with the impaired insulin activation of pyruvate dehydrogenase and glucose utilization seen in this model. These findings suggest that insulin stimulates breakdown of this glycophospholipid by stimulating an insulin-sensitive phospholipase in adipocytes. This compound may serve a function as a precursor for intracellular insulin mediators.

Muscle GLUT 4 Protein Levels and Impaired Triglyceride Metabolism in Streptozotocin Diabetic Rats.

1993 ◽  
Vol 683 (1 Dietary Lipid) ◽  
pp. 218-227 ◽  
Author(s):  
E. ŠEBÖKOVÁ ◽  
I. KLIMEŠ ◽  
R. MOSS ◽  
P. ŠTOLBA ◽  
M. M. L. WIERSMA ◽  
...  
Keyword(s):  
Diabetic Rats ◽  
Triglyceride Metabolism ◽  
Protein Levels ◽  
Glut 4 ◽  
Streptozotocin Diabetic Rats

Importance of medullary events in ammonium excretion: studies in acute respiratory and acute metabolic acidosis

1983 ◽  
Vol 61 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Andre Gougoux ◽  
Patrick Vinay ◽  
Guy Lemieux ◽  
Marc Goldstein ◽  
Bobby Stinebaugh ◽  
...  
Keyword(s):  
Metabolic Acidosis ◽  
Collecting Duct ◽  
Respiratory Acidosis ◽  
Renal Medulla ◽  
Hydrogen Ion ◽  
Ammonium Excretion ◽  
Urine Ph ◽  
Ion Secretion ◽  
Medullary Collecting Duct ◽  
Acute Metabolic Acidosis

The renal medulla can play an important role in acid excretion by modulating both hydrogen ion secretion in the medullary collecting duct and the medullary [Formula: see text]. The purpose of these experiments was to characterize the intrarenal events associated with ammonium excretion in acute acidosis. Cortical events were monitored in two ways: first, the rates of glutamine extraction and ammoniagenesis were assessed by measuring arteriovenous differences and the rate of renal blood flow; second, the biochemical response of the ammoniagenesis pathway was examined by measuring glutamate and 2-oxoglutarate, key renal cortical metabolites in this pathway. There were no significant differences noted in any of these cortical parameters between acute respiratory and metabolic acidosis. Despite a comparable twofold rise in ammonium excretion in both cases, the urine pH, [Formula: see text], and the urine minus blood [Formula: see text] difference (U-B [Formula: see text]) were lower during acute hypercapnia. In these experiments, the urine [Formula: see text] was 34 mmHg (1 mmHg = 133.322 Pa) lower than that of the blood during acute respiratory acidosis while the U-B [Formula: see text] was 5 ± 3 mmHg in acute metabolic acidosis. Thus there were significant differences in medullary events during these two conditions. Although the urine pH is critical in determining ammonium excretion in certain circumstances, these results suggest that regional variations in the medullary [Formula: see text] can modify this relationship.

Sorghum (Sorghum bicolor) Extract Affects Plasma Lipid Metabolism and Hepatic Macrophage Infiltration in Diabetic Rats

2020 ◽  
Vol 16 (5) ◽  
pp. 824-832 ◽  
Author(s):  
Yuuka Mukai ◽  
Saori Kataoka ◽  
Shin Sato
Keyword(s):  
Lipid Metabolism ◽  
Sorghum Bicolor ◽  
Plasma Lipid ◽  
Diabetic Rats ◽  
Macrophage Infiltration ◽  
Diabetic Rat ◽  
Hepatic Expression ◽  
Protein Levels ◽  
Chronic Hyperglycemia ◽  
Rat Livers

Background: Chronic hyperglycemia is known to be a high-risk factor for progressive chronic liver diseases, such as abnormal lipid metabolism. The activation of AMP-activated protein kinase (AMPK) has a beneficial effect on dyslipidemia. Polyphenols derived from various plants are involved in AMPK activation. Objective: We investigated the effects of polyphenol-containing sorghum (Sorghum bicolor) extract (SE) on plasma lipid metabolism and macrophage infiltration, and measured the expression and phosphorylation of AMPK and acetyl-CoA carboxylase (ACC) in diabetic rat livers. Methods: Streptozotocin-induced diabetic rats received 0, 50, or 250 mg/kg of SE orally for 4 weeks. Blood chemistry, total and phosphorylated protein levels of AMPK and ACC, sterol regulatory element- binding protein-1c (SREBP-1c) mRNA and protein levels, and macrophage infiltration in the livers were examined. Results: Plasma glucose and triacylglycerol levels, which were increased in the untreated diabetic rats, were significantly lower in the 250 mg/kg SE-treated diabetic rats. AMPK and ACC phosphorylation levels were significantly increased in the 250 mg/kg SE-treated diabetic rats compared with those in the untreated rats. There was no difference in the hepatic expression of SREBP-1c between the diabetic rat groups. Macrophage infiltration in the liver was suppressed by 250 mg/kg of SEtreatment. Conclusion: These data suggest that SE treatment may affect plasma lipid metabolism and chronic inflammation by upregulating phosphorylation of AMPK and ACC in diabetic rat livers.

Enhanced expression of epithelial sodium channels in the renal medulla of Dahl S rats

2011 ◽  
Vol 89 (3) ◽  
pp. 159-168 ◽  
Author(s):  
Md. Shahrier Amin ◽  
Erona Reza ◽  
Esraa El-Shahat ◽  
Hong-Wei Wang ◽  
Frédérique Tesson ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Young Male ◽  
Renal Medulla ◽  
High Salt ◽  
High Salt Diet ◽  
Salt Diet ◽  
Enhanced Expression ◽  
Mrna And Protein Expression ◽  
Medullary Collecting Duct ◽  
Apical Localization

Inner medullary collecting duct (IMCD) cells from salt-sensitive (S) Dahl rats transport twice as much Na+ as cells from salt-resistant (R) rats, possibly related to dysregulation of the renal epithelial sodium channel (ENaC). The effect of a high-salt diet on ENaC expression in the inner medulla of S versus R rats has not yet been studied. Young, male S and R rats were placed on a regular-salt (0.3%) or high-salt (8%) diet for 2 or 4 weeks. mRNA and protein expression of ENaC subunits were studied by real-time PCR and immunoblotting. Intracellular distribution of the subunits in the IMCD was evaluated by immunohistochemistry. On regular salt, the abundance of the mRNA of β and γENaC was higher in the medulla of S rats than R rats. This was associated with a greater protein abundance of 90 kDa γENaC and higher immunoreactivity for both α and γ ENaC. High salt did not affect mRNA abundance in either strain and decreased apical staining of βENaC in IMCD of R rats. In contrast, high salt did not affect the higher apical localization of αENaC and increased the apical membrane staining for β and γENaC in the IMCD of S rats. Expression of ENaC subunits is enhanced in the medulla of S vs. R rats on regular salt, and further increased on high salt. The persistent high expression of αENaC and increase in apical localization of β and γENaC may contribute to greater retention of sodium in S rats on a high-salt diet.

scholarly journals Fushiming Capsule Attenuates Diabetic Rat Retina Damage via Antioxidation and Anti-Inflammation

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Mengshan He ◽  
Pan Long ◽  
Lunfeng Guo ◽  
Mingke Zhang ◽  
Siwang Wang ◽  
...  
Keyword(s):  
Rat Model ◽  
Day Treatment ◽  
Outer Nuclear Layer ◽  
Diabetic Rats ◽  
Retinal Function ◽  
Diabetic Rat ◽  
Full Field ◽  
Rat Retina ◽  
Protein Levels ◽  
Diabetic Rat Model

Aims. Diabetic retinopathy (DR) remains one of the leading causes of acquired blindness. Fushiming capsule (FSM), a compound traditional Chinese medicine, is clinically used for DR treatment in China. The present study was to investigate the effect of FSM on retinal alterations, inflammatory response, and oxidative stress triggered by diabetes. Main Methods. Diabetic rat model was induced by 6-week high-fat and high-sugar diet combined with 35 mg/kg streptozotocin (STZ). 30 days after successful establishment of diabetic rat model, full field electroretinography (ffERG) and optical coherence tomography (OCT) were performed to detect retinal pathological alterations. Then, FSM was administered to diabetic rats at different dosages for 42-day treatment and diabetic rats treated with Calcium dobesilate (CaD) capsule served as the positive group. Retinal function and structure were observed, and retinal vascular endothelial growth factor-α (VEGF-α), glial fibrillary acidic (GFAP), and vascular cell adhesion protein-1 (VCAM-1) expressions were measured both on mRNA and protein levels, and a series of blood metabolic indicators were also assessed. Key Findings. In DR rats, FSM (1.0 g/kg and 0.5 g/kg) treatment significantly restored retinal function (a higher amplitude of b-wave in dark-adaptation 3.0 and OPs2 wave) and prevented the decrease of retinal thickness including inner nuclear layer (INL), outer nuclear layer (ONL), and entire retina. Additionally, FSM dramatically decreased VEGF-α, GFAP, and VCAM-1 expressions in retinal tissues. Moreover, FSM notably improved serum antioxidative enzymes glutathione peroxidase, superoxide dismutase, and catalase activities, whereas it reduced serum advanced glycation end products, methane dicarboxylic aldehyde, nitric oxide, and total cholesterol and triglycerides levels. Significance. FSM could ameliorate diabetic rat retina damage possibly via inhibiting inflammation and improving antioxidation.

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