ABSTRACT
Protein tyrosine phosphatase (PTP) 1B is a potential therapeutic target for type 2 diabetes. Phosphotyrosine (pTyr) mimetics still dominate the currently available PTP1B inhibitors. The phenoxyacetic acid moiety was taken as a pTyr mimetic herein and phenoxyacetic acid-based compounds 2a-2g and 3a-3c were designed. Among them, compounds 2a-2g exhibited potent inhibition against PTP1B, and compound 2g showed an IC50 of 0.42 μmol·L-1 against PTP1B. Compound 2f exhibited pharmacological profiles similar to that of rosiglitazone, and could improve the insulin sensitivity and the serum total cholesterol level. The results suggest that PTP1B inhibitors might be effective in treating type 2 diabetes as well as associated metabolic syndromes.
ABSTRACT
Xanthine oxidoreductase (XOR), the key enzyme catalyzing purine to produce uric acid, including two subtypes, xanthine dehydrogenase (XDH) and xanthine oxidase (XO), respectively, in vivo. Usually, XDH and XO can transform to each other. In this study, based on the principle that the subtype XO or XDH uses different electron acceptors, the methods for the measuring the activities of bovine milk XOR (pure enzyme) and its subtypes were established. The optimal concentrations of substrate xanthine (50 μmol·L-1) and electron acceptor NAD+ (50 μmol·L-1), pH value (7.80) were investigated. The ranges of the XOR, XO, XDH activity which could be determined were 0.97-17.5 U·L-1, 1-9 U·L-1, and 66-1 191 mU·L-1, respectively. Furthermore, the methods for determining the activities of XOR and its subtypes in mouse liver were established. The preparation of liver samples, the optimal concentrations of xanthine (100 μmol·L-1) and NAD+ (100 μmol·L-1) were researched. And the activity ranges of XOR, XO and XDH in mouse liver which could be determined were 0.67-3.98, 0.19-1.08, and 0.52-3.55 U·gprot-1, respectively. With the methods above, the effects of classic XOR inhibitor allopurinal (Allo) on XOR, XO and XDH from both milk and mouse liver were determined. All animal experiments have been approved by the Animal Experimental Center, Institute of Materia Medica, Chinese Academy of Medical Science and Peking Union Medical College (00003346). This study established new methods for the determination of XOR and its subtypes activity in pure enzyme system and in mouse liver, respectively, which were accurate and convenient. It laid the experimental foundation for exploring the different pathophysiological effects of XOR in the body and developing new XOR inhibitors.
ABSTRACT
Xanthine oxidase (XOD), catalyzing purine metabolism, is the key enzyme in uric acid (UA) biosynthesis, and becomes an important target for hyperuricemia treatment. The inhibition on XOD plays an important role in the treatment of hyperuricemia-related diseases, such as gout, as well as oxidative stress-induced tissue injury. Here, studies on the natural products with XOD inhibition are reviewed.
ABSTRACT
Hyperuricemia is not only the biochemical basis of gout, but also closely related to the development of metabolic syndrome, cardiovascular diseases, chronic kidney disease, etc. Xanthine oxidase (XOD) is the key catalytic enzyme for uric acid biosynthesis, therefore the vital target for anti-hyperuricemic drugs. In this study, compound CC18022 was designed and synthesized specifically targeting to XOD. Molecular docking analysis indicated a fairly tight binding between CC18022 and XOD. In the in vitro study, CC18022 significantly inhibited XOD activity with a half maximal inhibitory concentration (IC50) value in the order of nmol·L-1, which is relative to the XOD inhibitor febuxostat. By using both acute and chronic hyperuricemic mice model, compound CC18022 was found to have serum uric acid-lowering effect in a dose-dependent manner in vivo. The animal welfare and experimental processes were in accordance with the provisions of the Animal Ethics Committee of the Institute of Materia Medica, Chinese Academy of Medical Sciences. In the acute hyperuricemic mice, CC18022 significantly inhibited serum XOD activity, and also the XOD activity in intestine and liver, which were related to purine absorption and metabolism. Therefore, the novel compound CC18022 exhibited significant inhibition on XOD activity and anti-hyperuricemic effects, making it a favorable candidate for further research.
ABSTRACT
To investigate the effects of small molecule compound bicyclol on type 2 diabetes mellitus (T2DM) and its mechanism of action, KKAy mice were treated with various doses of bicyclol (100, 200, and 400 mg·kg-1·d-1) with metformin (200 mg·kg-1·d-1) as a positive control, respectively. Age-matched C57BL/6J mice were used as the non-diabetic control (Con). The effect on hyperglycemia was evaluated by the levels of no-fasting blood glucose, fasting blood glucose (FPG), and glucose tolerance. Whole body insulin sensitivity was evaluated by fasting plasma insulin (FPI) and homeostasis model assessment-insulin resistance (HOMA-IR). The hepatic response to insulin was evaluated by insulin-induced activation of insulin signaling pathway. Western blot was performed to detect hepatic protein expressions. All animal experimental procedures were approved by the Animal Ethics Committee of Chinese Academy of Medical Sciences. KKAy mice showed T2DM characteristics such as hyperglycemia and insulin resistance, including attenuated response to insulin in the liver. A 28-day treatment of bicyclol suppressed both FPG and no-fasting blood glucose, in a dose- and time-dependent manner. Moreover, FPI and HOMA-IR values were both significantly decreased, and hepatic insulin-induced-phosphorylation of IRβ and Akt were up-regulated in KKAy mice after bicyclol treatment. Phosphorylation of FoxO1, the key transcription factor for regulating gluconeogenesis, was also significantly elevated by bicyclol treatment. These results suggested that bicyclol has some therapeutic effects on hyperglycemia in a time- and dose-dependent manner in KKAy mice. Its mechanism might be attributed to improving insulin resistance, enhancing hepatic insulin signaling pathway, and inhibiting gluconeogenesis. No significant interference on the hypoglycemic effect of metformin by bicyclol was observed in this study.
ABSTRACT
Xanthine oxidase (XO) is a key enzyme in the synthesis of uric acid. Therefore, XO inhibitors play an important role in the antihyperuricemic therapy. Based on the template structures of febuxostat and topiroxostat, 18 amide derivatives were designed and synthesized. Among them, six showed apparent inhibitory activity against XO under the concentration of 10 μmol·L-1. Molecular docking revealed the possible interaction mode of this compound class, which may provide a clue for further molecular design.
ABSTRACT
Xanthine oxidase (XO) is an important target for the treatment of hyperuricemia and gout. Based on the two known non-purine xanthine oxidase inhibitors, febuxostat and topiroxostat, 14 oxadiazole derivatives have been designed and synthesized. These compounds have been evaluated against XO and five of them exhibited significant inhibitory activities at the concentrations below 10 μmol·L-1.
ABSTRACT
To investigate the effects and the mechanism of compound WS090152 on non-alcoholic fatty liver (NAFL), the compound was administrated in C57BL/6J mice fed a high fat diet at 50 mg·kg-1 by lavage. The lipid accumulation in liver was determined by the content of hepatic triglyceride (TG) and the histological pathological analysis. The levels of body weight gain, serum total cholesterol (TC) and TG were measured to evaluate lipid metabolism. Insulin sensitivity was determined by glucose infusion rate (GIR) value in hyperinsulinemic-euglycemic clamp test. The expression of related proteins in liver was measured by Western blot. The effect on the target protein tyrosine phosphatase 1B (PTP1B) was assessed by the activity of recombinate human PTP1B in vitro, and by the expressions of PTP1B in vivo, respectively. The content of hepatic TG (PPPPP50 value of 0.34 μmol·L-1; the expression of PTP1B was significantly downregulated, and the phosphorylation of its downstream insulin receptor (IR) and AKT was upregulated by WS090152 administration in the livers of NAFL mice. The expression of hepatic lipogenesis-related proteins-1c (SREBP-1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) was attenuated. These results suggest that compound WS090152 can ameliorate NAFL by increasing insulin sensitivity and decreasing hepatic lipogenesis probably through inhibition of PTP1B.
ABSTRACT
Based on the theory of traditional Chinese medicine, modern methods for drug investigation such as molecular targets in vitro and effects in vivo were used to study the prescription of Jingdan Yimin(JD), including selection of raw materials, composition, proportion, and effective dose of the compounds for treatment of metabolic syndrome. The IRF mice models, characterized by insulin resistance and hypercholesterolemia, were induced by high fat diet. The insulin sensitivity was estimated with insulin tolerance test(ITT) and glucose tolerance test(GTT); the levels of blood glucose and total cholesterol(TC), and the activities of α-glucosidase, protein tyrosine phosphatase 1B(PTP1B), and fructose phosphate amide transferase(GFAT)were measured with biochemical methods, respectively. The sample H13(h) extracted from Rhodiola crenulata, Y12(y) from Cordyceps militaris, and D(d) from Rheum palmatum were selected according to the inhibition activity on both PTP1B and α-glucosidase in vitro, regulation on hypercholesterolemia in IRF mice, and effects on GFAT activity, respectively; their synergistic effects on the treatment of metabolic syndrome were determined in IRF mice; composition proportion of h∶y∶d was measured in accordance with the results of L8(27) orthogonal experiments targeting on the inhibition of both PTP1B and α-glucosidase; finally, the effective dose was assessed based on the effects on IGT and hypercholesterolemia, respectively, in IRF mice. In conclusion, the prescription JD is composed by R. crenulata, C. militaris, and R. palmatum with the rate of 20∶1∶1, and its effective oral dose is 200 mg•kg⁻¹ for treatment of metabolic syndrome; its main mechanism is to inhibit the targets PTP1B and α-glucosidase. Monarch drug, R. crenulata, can clear away the lung-heat, tonify Qi, resolve stasis and nourish the heart. Adjuvant drug, C. militaris, can tonify the lung Qi and the kidney essence, strengthen waist and knee, accompanied with R. crenulata to enhance the function of invigorating lung and kidney. Assistant drug, rhubarb, can clear heat, detoxify, and remove blood stasis. These three herbs are compatible to show the effects of tonifying Qi, nourishing essence, clearing heat, reducing phlegm and resolving masses for the treatment of metabolic syndrome.
ABSTRACT
To investigate the effects of 2-(4-methoxycarbonyl-2-tetradecyloxyphenyl)carbamoylbenzoic acid (CX09040) on protecting pancreatic β cells, the β cell dysfunction model mice were induced by injection of alloxan into the caudal vein of ICR mice, and were treated with compound CX09040. Liraglutide was used as the positive control drug. The amount and the size of islets observed in pathological sections were calculated to evaluate the β cell mass; the glucose stimulated insulin secretion (GSIS) test was applied to estimate the β cell secretary function; the oral glucose tolerance test (OGTT) was taken to observe the glucose metabolism in mice; the expressions of protein in pancreas were detected by Western blotting. The effects on the target protein tyrosine phosphatase 1B (PTP1B) were assessed by the PTP1B activities of both recombinant protein and the intracellular enzyme, and by the PTP1B expression in the pancreas of mice, separately. As the results, with the treatment of CX09040 in alloxan-induced β cell dysfunction mice, the islet amount (P<0.05) and size (P<0.05) increased significantly, the changes of serum insulin in GSIS (P<0.01) and the values of acute insulin response (AIR, P<0.01) were enhanced, compared to those in model group; the impaired glucose tolerance was also ameliorated by CX09040 with the decrease of the values of area under curve (AUC, P<0.01). The activation of the signaling pathways related to β cell proliferation was enhanced by increasing the levels of p-Akt/Akt (P<0.01), p-FoxO1/FoxOl (P<0.001) and PDX-1 (P<0.01). The effects of CX09040 on PTP1B were observed by inhibiting the recombinant hPTP1B activity with IC50 value of 2.78x 10(-7) mol.L-1, reducing the intracellular PTP1B activity of 72.8% (P<0.001), suppressing the PTP1B expression (P<0.001) and up-regulating p-IRβ/IRβ (P<0.01) in pancreas of the β cell dysfunction mice, separately. In conclusion, compound CX09040 showed significant protection effects against the dysfunction of β cell of mice by enlarging the pancreatic β cell mass and increasing the glucose-induced insulin secretion; its major mechanism may be the inhibition on target PTP1B and the succedent up-regulation of β cell proliferation.
Subject(s)
Animals , Mice , Alloxan , Benzoates , Pharmacology , Biological Assay , Disease Models, Animal , Glucose , Metabolism , Glucose Tolerance Test , Insulin , Bodily Secretions , Insulin Resistance , Insulin-Secreting Cells , Liraglutide , Pharmacology , Mice, Inbred ICR , Molecular Weight , Pancreas , Protein Tyrosine Phosphatase, Non-Receptor Type 1 , Signal TransductionABSTRACT
Protein tyrosine phosphatase (PTP) 1B is a potential target for the treatment of diabetes and obesity. We have previously identified the benzoyl sulfathiazole derivative II as a non-competitive PTP1B inhibitor with in vivo insulin sensitizing effects. Preliminary SAR study on this compound series has been carried out herein, and thirteen new compounds have been designed and synthesized. Among them, compound 10 exhibited potent inhibition against human recombinant PTP1B with the IC50 value of 3.97 micromol x L(-1), and is comparable to that of compound II.
Subject(s)
Humans , Protein Tyrosine Phosphatase, Non-Receptor Type 1 , Structure-Activity Relationship , Sulfathiazoles , Chemistry , PharmacologyABSTRACT
To investigate the effect of compound FF16, compatibility of Rhodiola crenulata, Cordyceps militaris, and Rheum palmatum, on obesity, both the insulin resistant obese IRF mouse model induced by high fat diet and the spontaneous type 2 diabetes KKAy obese mouse model were used. The results showed that the body weights and the energy uptake were markedly reduced by compound FF16 in both IRF mice in dose-dependent manner and KKAy mice, respectively. Meanwhile, with the administration of FF16, the hypercholesterolemia and the hypertriglyceridemia were improved significantly in KKAy mice; and the levels of serum cholesterol and fatty index were decreased obviously, and the value of serum HDL-C was increased significantly in IRF mice, respectively. Moreover, the activity of a-glycosidase was inhibited by compound FF16 in vitro. In conclusion, FF16 could improve the obesity by inhibiting alpha-glycosidase activity.
Subject(s)
Animals , Mice , Cordyceps , Chemistry , Drugs, Chinese Herbal , Chemistry , Therapeutic Uses , Metabolic Syndrome , Drug Therapy , Mice, Obese , Obesity , Drug Therapy , Rheum , Chemistry , Rhodiola , ChemistryABSTRACT
Base on the improvement of compound FF16, compatibility of Rhodiola crenulata, Cordyceps militaris, and Rheum palmatum, on both insulin resistance and obesity, its effects on type 2 diabetes (T2DM ) was investigated here. The results showed that the levels of fasting and no-fasting blood glucose were controlled in the spontaneous type 2 diabetes KKAy mice; the impaired glucose tolerance (IGT)was improved by decreasing significantly the values of the glucose peaks and the area under the blood glucose-time curve (AUC ) after glucose-loading in glucose tolerance test (OGTT) in both high-fat-diet-induced pre-diabetes IRF mice and KKAy mice, respectively. The pancreatic histopathological analysis showed that the increased islet amount, the enlarged islet area, and the lipid accumulation in the pancreas were reversed by FF16 treatment in both IRF mice and KKAy mice. In the palmitate-induced RINm5f cell model, FF16 could effectively reduce the apoptosis and enhance the glucose-stimulated insulin secretion, respectively. In conclusion, FF16 could improve the T2DM by protecting the pancreatic beta-cells.
Subject(s)
Animals , Female , Humans , Mice , Blood Glucose , Metabolism , Cordyceps , Chemistry , Diabetes Mellitus, Type 2 , Drug Therapy , Metabolism , Drug Compounding , Drugs, Chinese Herbal , Insulin Resistance , Lipid Metabolism , Metabolic Syndrome , Drug Therapy , Metabolism , Mice, Inbred C57BL , Rheum , Chemistry , Rhodiola , ChemistryABSTRACT
This study is to investigate the effects of a Chinese prescription (FF), compatibility of Rhodiola crenulata, Cordyceps militaris and Rheum palmatum, on nephropathy in type 1 diabetic rats induced by streptozocin. According to fasting blood glucose level, diabetic rats were divided into three groups: model group, insulin-treated group and FF-treated group. Parameters for evaluating the glucose & lipid metabolism and the renal function were monitored dynamically. Levels of oxidative stress were detected ten weeks later. The results show that FF could significantly decrease the level of serum glucose and lipid profiles, improve the renal functions by decreasing blood urea nitrogen, urine albumin excretion and urease activity; FF could also affect on oxidative stress. In conclusion, Chinese prescription FF could ameliorate hyperglycemia-mediated renal damage in type 1 diabetic rats. These effects may be related to its regulation on the metabolism of glucose and lipid, the microcirculation disturbance and the oxidative stress.
Subject(s)
Animals , Humans , Male , Rats , Cordyceps , Chemistry , Diabetic Nephropathies , Drug Therapy , Metabolism , Drugs, Chinese Herbal , Herb-Drug Interactions , Hyperglycemia , Drug Therapy , Metabolism , Kidney , Wounds and Injuries , Metabolic Syndrome , Drug Therapy , Metabolism , Rats, Sprague-Dawley , Rhodiola , Chemistry , Rhus , ChemistryABSTRACT
To investigate the effects of a compound (FF16), compatibility of Rhodiola crenulata, Cordyceps militaris, and Rhum palmatum, on non-alcoholic fatty liver disease in IRF mice induced by high fat diet H&E stain was processed to evaluate the lipid accumulation in liver, and the dynamic microcirculation observation system was applied to determine hepatic microcirculation of IRF mice. Western blot was performed to evaluate IRS-2, HSL and ppar-alpha expression in liver. The results demonstrate that FF16 significantly decreased the liver lipid index and improved liver steatosis in IRF mice. Furthermore, FF16 could ameliorate hepatic microcirculation disturbance in IRF mice through enhancing RBC velocity and shear rates by 62.5% and 49.7%, increasing sinusoids perfusion by 70.0%, inhibiting adhered leukocytes in IRF mice. The abnormal expressions of IRS-2 and HSL were both reversed by the administration of FF16. In conclusion, FF16 could improve non-alcoholic fatty liver disease in IRF mice by improving insulin sensitivity, regulating lipid metabolism and improving microcirculation disturbance.
Subject(s)
Animals , Humans , Male , Mice , Cordyceps , Chemistry , Disease Models, Animal , Drugs, Chinese Herbal , Fatty Liver , Drug Therapy , Metabolism , Insulin Resistance , Lipid Metabolism , Liver , Metabolism , Metabolic Syndrome , Drug Therapy , Metabolism , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease , Rheum , Chemistry , Rhodiola , ChemistryABSTRACT
To investigate the mechanisms of a compound (FF16), compatibility of Rhodiola crenulata, Cordyceps militaris, and Rheum palmatum, on glucose metabolic disorders, the IRF mice charactered with insulin resistance and glucose metabolic disorders induced by high-fat diet in C57BL/6J mice were randomly divided into 3 groups; IRF, rosiglitazone (Rosi) and FF16. The glucose metabolism was evaluated by fasting blood glucose (FBG) levels and intraperitoneal glucose tolerance test (IPGTT). The insulin sensitivity was estimated by insulin tolerance test (ITT), fasting serum insulin levels and the index of HOMA-IR. The expressions of Akt and its phosphorylation levels, GSK3beta and its phosphorylation levels in liver were detected by Western Blot. The results showed that FF16 significantly improved the glucose metabolic disorders through reducing FBG by 15.1%, decreasing AUC values in glucose tolerance tests by 22.3%. FF16 significantly improved the insulin sensitivity through decreasing AUC values in insulin tolerance tests by 22.1%, reducing the levels of serum insulin by 42.9% and of HOMA-IR by 49.5%, comparing with model control, respectively. After the treatment with FF16, the levels of p-Akt and p-GSK3beta were increased by 116.4% and 24.9%, respectively, in the liver of IRF mice. In conclusion, compound FF16 could improve glucose metabolic disorders in IRF mice through enhancing the glyconeogenesis.
Subject(s)
Animals , Male , Mice , Cordyceps , Drugs, Chinese Herbal , Pharmacology , Therapeutic Uses , Glucose , Metabolism , Glycogen Synthase Kinase 3 , Metabolism , Glycogen Synthase Kinase 3 beta , Insulin Resistance , Metabolic Syndrome , Drug Therapy , Mice, Inbred BALB C , Phosphorylation , Proto-Oncogene Proteins c-akt , Metabolism , Rheum , RhodiolaABSTRACT
Protein tyrosine phosphatase (PTP) 1B is a potential target for the treatment of diabetes and obesity. Phosphotyrosine (pTyr) is the substrate for PTP1B dephosphorylation. Malonic acid moiety was used herein as a mimic of the phosphate group in pTyr, and novel malonic acid derivatives 1-7 were designed, synthesized and evaluated as PTP1B inhibitors. Results from enzymatic assays indicated that compounds 3 and 4 exhibited potent inhibition against human recombinant PTP1B with IC50 values of 7.66 and 1.88 micromol x L(-1), respectively.
Subject(s)
Humans , Drug Design , Enzyme Inhibitors , Chemistry , Pharmacology , Inhibitory Concentration 50 , Malonates , Chemistry , Pharmacology , Molecular Structure , Protein Tyrosine Phosphatase, Non-Receptor Type 1 , Metabolism , Structure-Activity RelationshipABSTRACT
To investigate the semi-quantitative method for evaluating the lipid accumulation in pancreas, the KKAy mice, a classical type 2 diabetes mellitus model mice, were used and treated with rosiglitazone (Rosi); and the age-matched C57BL/6J mice were used as normal control. Pancreas was fixed quickly for histological examination with HE staining. For the estimation of the lipid accumulation in pancreas, semi-quantitative method was designed: the number and the size of islet, lipid accumulation in islet and in exocrine gland were observed and the integrative score calculated under the microscope, separately. In KKAy mice, the characteristics of the increased amount of islet, the enlarged area of islet, an abundance of large vacuolations, lipid droplets, and fat proliferation were exposed frequently, and the integrative score increased 2.1 folds compared with that in C57BL/6J mice. Meanwhile, the levels of serum glucose, insulin, and triglyceride (TG) were 1.7, 18.0, and 9.0 times as those in C57BL/6J mice, respectively. With the rosiglitazone (10 mg x kg(-1)) treatment, compared with that in KKAy mice, the pancreatic pathological changes were ameliorated significantly, and the integrative score in KKAy + Rosi mice decreased by 28.9%; and the levels of serum glucose, insulin, and triglyceride decreased by 48.3%, 81.3% and 64.1%, respectively. It showed there is a correlation between the pancreatic pathological semi-quantitative score and the values of serum parameters. In conclusion, this semi-quantitative scoring method is simple and objective for the evaluation of lipid accumulation in pancreas of mice.
Subject(s)
Animals , Female , Mice , Blood Glucose , Metabolism , Diabetes Mellitus, Type 2 , Blood , Metabolism , Pathology , Hypoglycemic Agents , Pharmacology , Insulin , Blood , Islets of Langerhans , Metabolism , Pathology , Lipid Metabolism , Mice, Inbred C57BL , Pancreas , Metabolism , Pathology , Random Allocation , Thiazolidinediones , Pharmacology , Triglycerides , BloodABSTRACT
<p><b>OBJECTIVE</b>To study the hypoglycemic effect of the extract of B. polyandra (SHG).</p><p><b>METHOD</b>The diabetic mice were induced by alloxan in ICR mice. The blood glucose concentration was measured by glucose oxidase method. The serum insulin level was determined by 125I-insulin radioimmunoassay kit. The hypoglycemic effect was evaluated by the levels of both fasting and no-fasting blood glucose. The effect on serum insulin level was estimated by the values of the blood insulin and the changes of the blood glucose induced by the glucose intraperitoneal injection. The effect on the glucose absorption was investigated by the oral sucrose or starch tolerance test.</p><p><b>RESULT</b>Both of the fasting and no-fasting blood glucose levels were decreased significantly by the treatment of 20 or 30 g raw materials crude drug x kg (-1) SHG orally for 7-10 d in ICR mice or in alloxan diabetic mice. In the oral sucrose tolerance test or oral starch tolerance test, the administration of SHG reduced significantly the peak value of the blood glucose and the area under the blood glucose-time curve (AUC) in normal or alloxan diabetic mice, respectively. These effects of SHG were similar to those of acarbose, a kind of alpha-glucosidase inhibitors. In the oral glucose tolerance test in normal and alloxan diabetic mice, SHG decreased both the blood glucose peak and the AUC induced by the glucose loading. But in the intraperitoneal injection glucose tolerance test the levels of insulin in both SHG and control mice were similar, however, the changes of the blood glucose level after the glucose-loading for 30 min in SHG mice was much lower than that in control mice.</p><p><b>CONCLUSION</b>With the treatment of SHG, the fasting and no-fasting blood glucose concentrations were decreased and the glucose tolerance improved significantly in both normal and alloxan diabetic mice, and the inhibition of a-glucosidase might be one of its major mechanisms.</p>
Subject(s)
Animals , Male , Mice , Administration, Oral , Alloxan , Area Under Curve , Blood Glucose , Diabetes Mellitus, Experimental , Blood , Drugs, Chinese Herbal , Pharmacology , Glucose , Pharmacokinetics , Glucose Tolerance Test , Hypoglycemic Agents , Pharmacology , Injections, Intraperitoneal , Insulin , Blood , Mice, Inbred ICR , Phytotherapy , Plants, Medicinal , Chemistry , Random Allocation , alpha-Glucosidases , MetabolismABSTRACT
<p><b>AIM</b>To set up an IR-HIRc cell model for screening the inhibitor of GFAT (glutamine: fructose-6-phosphate amidotransferase) , the key enzyme in the hexosamine biosynthesis pathway (HBP).</p><p><b>METHODS</b>For GFAT activity assay, the GDH method was improved by adjusting the value of pH in the reaction system and the concentrations of the reactants. The sensitivity to insulin in the cells was estimated by the measurement of insulin-induced glucose-uptake. The IR-HIRc model was set up by the stimulation of long-action insulin for 36 h. The IR-HIRc model and GDH method was used for screening GFAT inhibitor.</p><p><b>RESULTS</b>With the administration of 25 nmol x L(-1) long-action insulin in HIRe cells for 36 hours, the GFAT activity increased by 47% and the insulin-induced glucose-uptake decreased by 21%. Azaserine, a GFAT inhibitor, inhibited GFAT activity significantly in a dose-dependent manner in IR-HIRc model.</p><p><b>CONCLUSION</b>With the stimulation of 25 nmol x L(-1) long-action insulin for 36 h, excess hexosamine flux and insulin resistant in IR-HIRc cell model was set up, which can be used for screening</p>