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21.
The effect of oral administration of sodium orthovanadate (SOV) and Trigonella foenum graecum seed powder (TSP), a medicinal plant used extensively in Asia, on the mitochondrial metabolism in the alloxan diabetic rats has been investigated. Rats were injected with alloxan monohydrate (20 mg/100 g body wt) or vehicle (Na-acetate buffer), the former were treated with either 2 IU insulin i.p., 0.6 mg/ml SOV ad libitum, 5% TSP ad libitum, and a combination of 0.2% SOV and 5% TSP ad libitum for 21 days. Selected rate-limiting enzymes of the tricarboxylic acid cycle, hydrogen shuttle system, ketone body metabolism, amino acid metabolism and urea cycle were measured in the mitochondrial and cytosolic fractions of liver, kidney and brain tissues of the experimental rats. Majority of the mitochondrial enzymes in the tissues of the diabetic rats had significantly higher activities compared to the control rats. Similarly, the activities of mitochondrial and cytosolic aminotransferases and arginase were significantly higher in liver and kidney tissues of the diabetic rats. The separate administrations of SOV and TSP to diabetic rats were able to restore the activities of these enzymes to control values. The lower dose of SOV (0.2%) administered in combination with TSP to diabetic rats lowered the enzyme activities more significantly than when given in a higher dose (0.6%) separately. This is the first report of the effective combined action of oral SOV and TSP in ameliorating the altered mitochondrial enzyme activities during experimental type-1 diabetes. Our novel combined oral administration of SOV and TSP to diabetic rats thus conclusively proves as a possible method to minimize potential vanadate toxicity without compromising its positive effects in the therapy of experimental type-1 diabetes. 相似文献
22.
Vascular smooth muscle cell growth and insulin regulation of mitogen-activated protein kinase in hypertension 总被引:4,自引:0,他引:4
Begum Najma; Song Young; Rienzie Jennifer; Ragolia Louis 《American journal of physiology. Cell physiology》1998,275(1):C42
Hyperinsulinemia (HI) and insulin resistance (IR) are frequentlyassociated with hypertension and atherosclerosis. However, the exactroles of HI and IR in the development of hypertension are unclear.Mitogen-activated protein kinases (MAPK) are well-characterized intracellular mediators of cell proliferation. In this study, weexamined the contribution of MAPK pathway in insulin-stimulated mitogenesis using primary vascular smooth muscle cells (VSMCs) isolatedfrom aortas of normotensive Wistar-Kyoto rats (WKY) and spontaneoushypertensive rats (SHR). VSMCs were grown to confluence in culture,serum starved, and examined for DNA synthesis {using [3H]thymidine (TDR),immunoprecipitated MAPK activity, and MAPK phosphatase (MKP-1)induction}. Basal rate of TDR incorporation into DNA was twofoldhigher in SHR compared with WKY (P < 0.005). Insulin caused a dose-dependent increase in TDR incorporation (150% over basal levels with 100 nM in 12 h). Stimulation was sustained for 24 h with a decline toward basal in 36 h. Pretreatment with insulin-like growth factor I (IGF-I) receptor antibody did notabolish mitogenesis mediated by 10-100 nM insulin, suggesting thatinsulin effect is mediated via its own receptors. Insulin had a smallmitogenic effect in WKY (33% over basal). Insulin-stimulated mitogenesis was accompanied by a dose-dependent increase in MAPK activity in SHR, with a peak activation (>2-fold over basal) between 5 and 10 min with 100 nM insulin. Insulin had very small effects onMAPK activity in WKY. In contrast, serum-stimulated MAPK activation wascomparable in WKY and SHR. Pretreatment with MEK inhibitor, PD-98059,completely blocked insulin's effect on MAPK activation andmitogenesis. Inhibition of phosphatidylinositol 3-kinase with wortmannin also prevented insulin's effects on MAPK activation andmitogenesis. In WKY, insulin and IGF-I treatment resulted in a rapidinduction of MKP-1, the dual-specificity MAPK phosphatase. Incontrast, VSMCs from SHR were resistant to insulin with respect toMPK-1 expression. We conclude that insulin is mitogenic in SHR, and theeffect appears to be mediated by sustained MAPK activation due toimpaired insulin-mediated MKP-1 mRNA expression, which may act asan inhibitory feedback loop in attenuating MAPK signaling. 相似文献
23.
Arbuscular Mycorrhizal Fungi Enhance Zinc and Nickel Uptake from Contaminated Soil by Soybean and Lentil 总被引:1,自引:0,他引:1
Atif Jamal Najma Ayub Muhammad Usman Dr. Abdul G. Khan 《International journal of phytoremediation》2002,4(3):205-221
Generally, soils in Pakistan are deficient in P and N. Due to intensive cropping and irrigation, Pakistani soils have also become deficient in micronutrients such as Zn, Fe, Cu, and Mn. Arbuscular mycorrhizal fungi, which form symbiotic associations with roots of most land plants, are known to enhance uptake of P and trace elements such as Cu, Ni, Pb, and Zn. The present study was conducted to investigate the role of arbuscular mycorrhizae (AM) in uptake of nickel (Ni) and zinc (Zn) by crops viz. soybean (Glycine max (L.) Merrill) and lentil (Lens culinaris Medic). Zn and Ni were applied as ZnSO4 7H2O and NiCl2 respectively, in four concentrations (0.0, 1.0, 3.0, and 5.0 g kg-1 soil). AM inoculum consisted of sand containing sporocarps, spores, and AMF infected root pieces from a pot culture of Glomus mosseae. Control plants received pot culture filtrate containing soil microflora minus AM fungal propagules. A significant difference (p < 0.05) was observed in the dry weights of roots and shoots of the mycorrhizal (M) and nonmycorrhizal (NM) cereal plants. The sievate-amended treatments did not stimulate plant growth to the same extent as the AM fungal amended treatments. Trace metals inhibited the extent of mycorrhizal colonization of the cereal roots. The concentrations of the trace metals in the plant tissues of 12-week old cereal plants were found significantly (p < 0.05) higher in M than NM plants. These results indicate that mycorrhize can be used as effective tools to supply sufficient Zn in generally Zn-deficient Pakistani soils and to ameliorate the toxicity of trace metals in polluted soils. The contents of Ni in mycorrhizal soybean plant tissues were higher than those in the mycorrhizal lentil plant tissues. The implications of these results in mycorrhizo remediation of agricultural soils are discussed. 相似文献
24.
25.
Milena Sochor Najma Zaheer Baquer John S. Hothersall Patricia McLean 《Biochemical and biophysical research communications》1978,80(3):533-539
Measurements have been made of the activity of ornithine decarboxylase of liver, heart, kidney and brain in alloxan-diabetic and control rats. In all these tissues this enzyme had decreased markedly at four weeks after induction of diabetes. These results are discussed in relation to the hormonal control and cyclic nucleotide regulation of ornithine decarboxylase. 相似文献
26.
27.
The reticulocytes and the ageing red blood cells (RBCs) namely young (Y), middle-aged (M) and old RBCs (O) of female Wistar
rats from different groups such as control animals (C), controls treated with vanadate (C + V), alloxan-induced diabetic (D),
diabetic-treated with insulin (D + I) and vanadate (D + V), were fractionated on a percoll/BSA gradient. The following enzymes
were measured-hexokinase (HK), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), glutathione-s-transferase
(GST), alanine aminotransferase ΜlaAT), aspartate aminotransferase ΜsAT) and arginase in the hemolysates of all the RBCs fractions.
Decreases in the activity of HK and AsAT by about 70%, arginase and GSH-Px by 30% in old RBCs were observed in comparison
to reticulocytes of control animals. Increases in the activity of GSSG-R by 86%, AlaAT by more than 400% and GST by 70% were
observed in old RBCs in comparison to reticulocytes of control animals.
Alloxan diabetic animals showed a further decrease in the activities of HK in Y RBCs by 37%, M RBCs by 39% and O RBCs by 32%,
GSH-Px activity in Y RBCs by 13%, M RBCs by 20% and O RBCs by 33% and GST activity in Y RBCs by 14%, M RBCs by 42% and O RBCs
by 60% in comparison to their corresponding cells of control animals. An increase in the activity of all the enzymes studied
was also observed in reticulocytes of diabetic animals in comparison to reticulocytes of controls. The GSSG-R activity was
found to be increased in Y RBCs by 49%, M RBCs by 67% and O RBCs by 64% as compared to the corresponding age-matched cells
of control animals. The activity of arginase also decreased in Y RBCs by about10%, M RBCs by 20% and O RBCs by 30% in comparison
to the age-matched cells of control animals. A decrease in the activity of AsAT in Y and M RBCs by 30%, and O RBCs by 25%
was observed in diabetic animals in comparison to the agematched cells of control animals. The activity of AlaAT was found
to be decreased by more than 10% in Y and M RBCs and 25% in O RBCs of diabetic animals in comparison to the age-matched cells
of control animals.
Insulin administration to diabetic animals reversed the altered enzyme activity to control values. Vanadate treatment also
reversed the enzyme levels except for that of GST in old cells 相似文献
28.
Sodium-orthovanadate (SOV) and seed powder ofTrigonella foenum graecum Linn. (common name: fenugreek, family: Fabaceae) (TSP) besides being potential hypoglycemic agents have also been shown to
ameliorate altered lipid metabolism during diabetes. This study evaluates the short-term effect of oral administration of
SOV and TSP separately and in concert (for 21 days) on total lipid profile and lipogenic enzymes in tissues of alloxan diabetic
rats. Diabetic rats showed 4-fold increase in blood glucose. The level of total lipids, triglycerides and total cholesterol
in blood serum increased significantly during diabetes. During diabetes the level of total lipids increased significantly
(P < 0001) in liver and in kidney by 48% and 55%, respectively, compared to control. Triglycerides level increased by 32% (P < 001) in liver and by 51% (P < 0005) in kidney, respectively, compared to control. Total cholesterol level also increased significantly in both liver
and kidney (P < 0.01 andP < 0001, respectively). The activities of NADP-linked enzymes; namely glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme
(ME), isocitrate dehydrogenase (ICDH), and the activities of lipogenic enzymes namely ATP-citrate lyase ΜTP-CL) and fatty
acid synthase (FAS) were decreased significantly in liver and increased in kidney during diabetes as compared to control.
SOV and TSP administration to diabetic animals prevented the development of hyperglycemia and alteration in lipid profile
in plasma and tissues and maintained it near normal. Maximum prevention was observed in the combined treatment with lower
dose of SOV (0.2%) after 21 days. We are presenting for the first time effectiveness of combined treatment of SOV and TSP
in amelioration of altered lipid metabolism during experimental type-I diabetes 相似文献
29.
30.
Cryptosporidium p30, a galactose/N-acetylgalactosamine-specific lectin, mediates infection in vitro 总被引:1,自引:0,他引:1
Cryptosporidium sp. cause human and animal diarrheal disease worldwide. The molecular mechanisms underlying Cryptosporidium attachment to, and invasion of, host cells are poorly understood. Previously, we described a surface-associated Gal/GalNAc-specific lectin activity in sporozoites of Cryptosporidium parvum. Here we describe p30, a 30-kDa Gal/GalNAc-specific lectin isolated from C. parvum and Cryptosporidium hominis sporozoites by Gal-affinity chromatography. p30 is encoded by a single copy gene containing a 906-bp open reading frame, the deduced amino acid sequence of which predicts a 302-amino acid, 31.8-kDa protein with a 22-amino acid N-terminal signal sequence. The p30 gene is expressed at 24-72 h after infection of intestinal epithelial cells. Antisera to recombinant p30 expressed in Escherichia coli react with an approximately 30-kDa protein in C. parvum and C. hominis. p30 is localized to the apical region of sporozoites and is predominantly intracellular in both sporozoites and intracellular stages of the parasite. p30 associates with gp900 and gp40, Gal/GalNAc-containing mucin-like glycoproteins that are also implicated in mediating infection. Native and recombinant p30 bind to Caco-2A cells in a dose-dependent, saturable, and Gal-inhibitable manner. Recombinant p30 inhibits C. parvum attachment to and infection of Caco-2A cells, whereas antisera to the recombinant protein also inhibit infection. Taken together, these findings suggest that p30 mediates C. parvum infection in vitro and raise the possibility that this protein may serve as a target for intervention. 相似文献