Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rats treated with streptozotocin for 17 days were used to determine the cellular origin of enhanced brush border glucose transport in the diabetic small intestine. In the jejunum of both normal and diabetic rats, phlorizin-sensitive (SGLT1-mediated) glucose transport was shown, by section autoradiography, to take place in upper villus enterocytes. The distribution of brush border SGLT1 transporters along villi, determined using immunogold cytochemistry, was similar to that found for glucose uptake. Longer villi, supporting a larger number of absorbing enterocytes in the diabetic jejunum, appeared to be responsible for increased glucose uptake in this condition. SGLT1 protein and SGLT1-mediated glucose transport were undetectable in normal distal ileal villi. However, following treatment with streptozotocin, both SGLT1 protein and SGLT1-mediated glucose transport were found to be present in basal ileal villus enterocytes. SGLT1 protein and SGLT1-mediated glucose transport both increased during enterocyte migration to the villus tip. Cellular induction of the SGLT1 transporter, as well as longer villi contribute to enhanced glucose transport in diabetic rat distal ileum. Close correlation between the positional expression of SGLT1 protein and absorptive function suggests that transporter density is an important determinant for up-regulation of sodium-dependent glucose transport in diabetes.
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PMID:The effects of streptozotocin diabetes on sodium-glucose transporter (SGLT1) expression and function in rat jejunal and ileal villus-attached enterocytes. 767 26

Diabetes mellitus is characterized by alterations in the intrarenal renin-angiotensin system, including decreases in glomerular angiotensin II (Ang II) receptor density. Since Ang II regulates proximal tubule transport function, the present studies examined whether diabetes altered expression of proximal tubule receptors. In basolateral membranes from 14 day streptozotocin-induced diabetic rats, specific binding of 125I Ang II was decreased to 53 +/- 8% of control (3.2 +/- 0.5 vs. 1.5 +/- 0.2 fmol/mg protein; N = 7; P < 0.02). Similarly, in proximal tubule brush border membranes from diabetic animals, specific binding was decreased to 63 +/- 11% of control (1.1 +/- 0.2 vs 0.6 +/- 0.1 fmol/mg protein; N = 9; P < 0.05). Concomitant insulin treatment reversed the decrease in specific binding of 125I Ang II to basolateral membranes (109 +/- 26% of control; N = 3) and to brush border membranes (85 +/- 17% of control; N = 6). In order to determine if changes in expression of type-1 Ang II receptors (AT1R) accompanied the changes in binding, quantitative polymerase chain reaction of AT1R mRNA was performed and expressed as the ratio of the amplified AT1R to that of an Msc1/Msc1 internal deletion mutant and normalized to that of beta-actin. In total RNA from proximal tubule suspensions of diabetic animals, AT1R mRNA expression decreased by 38% (21 +/- 3 vs. 13 +/- 2 cpm AT1R/cpm deletion mutant/cpm beta actin/10(6); N = 4; P < 0.0025). Insulin treatment reverted AT1R mRNA expression to control levels (22 +/- 3 cpm AT1R/cpm deletion mutant/cpm beta actin/10(6); P < 0.001 compared to the untreated group).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reduced proximal tubule angiotensin II receptor expression in streptozotocin-induced diabetes mellitus. 770 17

Acarbose is an alpha-glucosidase inhibitor proposed for the treatment of diabetic patients. It acts by competitively inhibiting the alpha-glucosidases in the intestinal brush border. The principal action of these enzymes is to convert nonabsorbable dietary starch and sucrose into absorbable monosaccharides (e.g. glucose). Enzyme inhibitors delay this conversion, slowing the formation and consequently the absorption of monosaccharides, and thus reducing the concentration of postprandial blood glucose. Both starch and sucrose are influenced, whereas lactose and glucose are not. Many studies in experimental animals, healthy volunteers and patients with non-insulin-dependent diabetes mellitus (NIDDM) have shown that acarbose decreases postprandial blood glucose, with a lesser reduction of fasting blood glucose, plasma triglycerides and postprandial insulin levels. In long term studies in NIDDM patients, acarbose significantly reduced glycosylated haemoglobin levels. Acarbose is only minimally absorbed from the gut and no systemic adverse effects have been demonstrated after long term administration. The drug allows undigested carbohydrates to pass into the large bowel where they are fermented causing flatulence, bloating and diarrhoea. These symptoms, which occur in approximately 30 to 60% of patients, tend to decrease with time and seem to be dose-dependent. They are minimised by starting therapy with low doses (such as 50mg 3 times daily) which may be effective in many patients. An increase in serum hepatic transaminases observed in earlier studies in the US, where doses of acarbose up to 900mg daily were used, has been not reported with the lower doses of the drug actually recommended [150 to 300mg (up to 600mg) daily]. In conclusion, acarbose may be useful in patients with NIDDM when diet alone is no longer able to maintain satisfactory blood glucose control. Furthermore, it may be a valid alternative to sulphonylurea or biguanide therapy when these drugs are contraindicated and insulin administration may be delayed. Acarbose seems also to be a useful adjunct to hypoglycaemic oral agents but its precise role in this field has not been fully clarified.
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PMID:A risk-benefit appraisal of acarbose in the management of non-insulin-dependent diabetes mellitus. 772 53

Diabetes-associated changes in intestinal uptake of nutrients are modified by isocaloric variations in the type of dietary lipids, and are associated with alterations in the phospholipid and fatty acyl content of the intestinal brush border membrane. The present study was designed to test the hypothesis that diet- and diabetes-associated changes in enterocyte microsomal membrane phospholipids are due to variations in the activity of two phospholipid metabolizing enzymes, 1,2-diacylglycerol:CDPcholine cholinephosphotransferase (CPT) and phosphatidylethanolamine methyltransferase (PEMT). Adult female Wistar rats were fed one of four semisynthetic diets--beef tallow low in cholesterol (BT), beef tallow high in cholesterol (BTC), fish oil low in cholesterol (FO) or fish oil high in cholesterol. In half of the animals, diabetes mellitus was produced by injection of streptozotocin. Jejunal and ileal enterocyte microsomes (EMM) were isolated and analyzed for cholesterol and phospholipids, as well as for CPT and PEMT activities. In control animals, feeding FO reduced EMM total phospholipids including phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol. Feeding FO resulted in a greater than 95% reduction in the activity of CPT. Diabetes was associated with increased jejunal EMM total phospholipids including sphingomyelin (SM) and PE, without associated changes in CPT or PEMT. Dietary cholesterol supplementation did not affect EMM total cholesterol or phosphlipid composition in control rats fed BT or FO, but was associated with an increase in EMM cholesterol in diabetic rats fed BT or FO. A decrease in total phospholipids due to a decline in SM, PC and PE in diabetic rats fed FO was not associated with changes in the activities of CPT or PEMT in EMM.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Dietary omega 3 fatty acids and cholesterol modify enterocyte microsomal membrane phospholipids, cholesterol content and phospholipid enzyme activities in diabetic rats. 785 11

The effect of infusion (2 h) of various sugars (20%, w/v) or early diabetes mellitus (2 h following injection of streptozotocin) on the potential difference (PD) across the brush border of rat jejunum has been studied in vitro. Infusion of glucose or galactose resulted in hyperpolarization of the brush-border PD (-55.2 and -54.9 mV respectively) compared with mannitol-infused animals (-47.7 mV). Infusion of fructose and alpha-methyl glucoside was without effect on PD. Ion substitution experiments showed that the glucose infusion-induced hyperpolarization was due either to a decrease in Cl- conductance and/or increased K+ conductance of the brush-border membrane. Na+ conductance appeared to be unaltered in these experiments. Since galactose infusion hyperpolarized PD without elevating plasma glucose or insulin levels, it seems that neither glucose nor insulin alone is responsible for the significantly greater PD. Treatment with streptozotocin produced glycosuria and hyperglycaemia within approximately 90 min and animals were used 30-60 min later. PD in streptozotocin-treated animals (-51.8 mV) was significantly greater than that measured in diluent-injected animals (-45.3 mV, P < 0.001). However, unlike the situation with sugar infusion, ion substitution experiments showed that the hyperpolarization seen in diabetic animals was due to a decreased Na+ conductance of the brush-border membrane. Since the magnitude of the brush-border PD dictates the electrochemical driving force for Na(+)-sugar cotransport, our data represent the first evidence for an effect of acute hyperglycaemia on the capacity for brush border sugar uptake. However, the enterocyte and systemic factors responsible for the membrane hyperpolarization are unclear.
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PMID:The effect of rapid changes in plasma sugar concentration on the brush-border potential difference in rat jejunum. 807 54

A prospective open clinical trial was carried out with 23 hypertensive type I diabetics (13 men, ten women, mean age 49 +/- 9.1 years, duration of diabetes 18 +/- 9.1 years) with early nephropathy. Glomerular and tubular renal function and metabolic parameters were monitored during 8 months' treatment with the angiotensin converting enzyme (ACE) inhibitor, captopril, in addition to previous antihypertensive treatment with one or more drugs. Blood pressure control tended to improve on captopril (systolic pressures 152 +/- 13 vs 140 +/- 13 mm Hg, P < 0.05; diastolic pressures 89 +/- 10 vs 87 +/- 10 mm Hg, not significant). Proteinuria (> 0.5 g/24 hours) fell into the microalbuminuria range (albumin excretion 2-20 mg/mmol creatinine) in four out of 13 patients, and microalbuminuria disappeared in four out of ten patients. Urinary levels of the brush border enzyme N-acetyl-beta-D-glucosaminidase (NAG), a marker of tubular dysfunction, were initially raised and fell significantly after 8 months' treatment with captopril (20.3 +/- 14.4 vs 8.8 +/- 8.1 U/g creatinine; P < 0.01). Captopril did not affect metabolic control (HbA1, total, HDL and LDL cholesterol, triglycerides, apolipoproteins A1 and B) or the insulin dosage. These results show that long-term treatment with captopril may favourably influence both albumin excretion and NAG activity, a marker of tubular dysfunction, in type I diabetics with nephropathy.
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PMID:[The effect of blood pressure-reducing therapy with captopril on tubular marker excretion in type-1 diabetics with nephropathy]. 820 41

Microalbuminuria (26-250 mg/d) is considered to be an indicator of incipient diabetic nephropathy in humans in insulin-dependent diabetes (IDD). However, before microalbuminuria is observed, glomerular alterations, such as glycosylation of the glomerular basement membrane and glomerular hyperfiltration, in IDD may result in increased filtration of albumin before any observed increase in albumin excretion. Glomerular and tubular albumin kinetics were examined in streptozotocin (65 mg/kg body wt, i.v.) diabetic, Munich-Wistar rats at 7-10 (untreated) and 50-70 d (poorly controlled with small doses of insulin) after the onset of diabetes and compared with nondiabetic controls. Additional rats in each condition received acute lysine treatment to prevent tubular protein reabsorption. Urinary albumin excretion and nonvascular albumin distribution volumes were measured in the renal cortex and compared with morphometric measurements of interstitial space and the proximal tubule to assess intracellular uptake of albumin in the proximal tubule. Urinary albumin excretion under anesthesia was not different in 7-10-d IDD versus controls (19 +/- 3 vs. 20 +/- 3 micrograms/min) but increased in the 50-70-d IDD (118 +/- 13 micrograms/min, P < 0.05). Lysine treatment resulted in increased albumin excretion compared with respective nontreatment in 7-10-d IDD (67 +/- 10 micrograms/min, P < 0.05) but not in controls (30 +/- 6 micrograms/min) or in 50-70-d IDD (126 +/- 11 micrograms/min). Glomerular filtration rate was increased both in 7-10-d IDD (2.7 +/- 0.1 ml/min, P < 0.05) and in 50-70-d IDD (2.6 +/- 0.1 ml/min, P < 0.05) compared with control (2.2 +/- 0.1 ml/min). Calculated urinary space albumin concentrations increased early in IDD with 2.5 +/- 0.4 mg% in 7-10-d IDD and 4.9 +/- 0.6 mg% in 50-70-d IDD compared with control (1.4 +/- 0.3 mg%). The increase in filtration of albumin is in excess of that attributable to hyperfiltration before increased albumin excretion early in diabetes. In 50-70-d IDD, absolute tubular reabsorption of albumin is decreased, correlating to the decrease in brush border height of the proximal tubule.
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PMID:Glomerular filtration and tubular reabsorption of albumin in preproteinuric and proteinuric diabetic rats. 834 7

Rat intestines revealed a significant loss of proteins after seven days of alloxan induced diabetes. The data suggested the presence of two forms of alkaline phosphatase (ALP) in normal rat intestines. Along with the loss of proteins from the intestines during diabetes, a form of ALP which appears to be loosely bound to the intestine is also flushed out. Total brush border membrane (BBM) proteins are relatively preserved from such leaching effect of alloxan induced diabetes. Thus, sucrase and another form of ALP which appears to be strongly bound to the BBM are flushed out at a slower rate as compared to the other intestinal proteins and loosely bound soluble ALP. BBM preparations from diabetic rat intestines showed lower ratios for BBM/intestinal homogenate sucrase or ALP activity/mg proteins as compared to the normal control rats. Such ratios, therefore, misdepict the purity as low for the BBM from diabetic rats which is merely because of the decreased contents of proteins in the intestinal homogenate during alloxan-induced acute experimental diabetes.
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PMID:Alterations in rat intestinal sucrase and alkaline phosphatase activities in alloxan induced experimental diabetes. 840 49

Several alterations were observed in the rat intestinal brush border membrane (BBM) lipid composition after 7 days old alloxane-induced diabetes as compared to the control animals. There was no change in the total protein contents but a significant increase in the total lipid contents was observed. Glycolipids constituting the major lipid components showed a two-fold increase. No significant difference was observed in the total phospholipid contents. A significant decline in the free cholesterol (CH) level, free fatty acids, triglycerides and sialic acid contents was observed in membranes from diabetic rats. Esterified CH, monoglycerides+diglycerides, phosphatidyl serine+phosphatidyl inositol and phosphatidyl choline levels remained unaffected. A significant increase in sphingomyelin with a parallel decrease in phosphatidyl ethanolamine was observed in BBM preparations from diabetic rats. The observed changes in intestinal BBM might be responsible for altered functions of the diabetic intestines.
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PMID:Lipid composition of intestinal brush border membrane in alloxan induced acute experimental diabetes. 840 97

Activity of renal meprin, a membrane-bound proteinase in the proximal tubule brush border, was measured in normal rats and in two disease groups: chronic puromycin aminonucleoside nephropathy for 12 weeks and streptozocin-induced diabetes for 6 months. Enzyme activity in kidney homogenates was assayed using azocasein as substrate. The mean activity of mephrin was 3.22 +/- 0.34 U/g kidney weight in normal rats. In diabetic animals, enzyme activity was 8.58 +/- 2.11 U/g kidney weight, P < 0.01. In contrast, meprin activity was decreased in rats with puromycin-induced glomerulopathy, 2.13 +/- 0.17 U/g kidney weight, P < 0.01. These findings indicate that meprin activity is elevated in experimental diabetes. Diminished activity of this luminal membrane enzyme in puromycin aminonucleoside nephropathy may contribute to renal injury in this disease model associated with massive urinary protein excretion.
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PMID:Meprin activity in rats with experimental renal disease. 841 99


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