Objective： To explore the molecular mechanism of puerarin （Pue） in improving insulin resistance through observing its effect on the insulin resistance of 3T3-Li lipocyte induced by free fatty acid （FFA）. Methods...Objective： To explore the molecular mechanism of puerarin （Pue） in improving insulin resistance through observing its effect on the insulin resistance of 3T3-Li lipocyte induced by free fatty acid （FFA）. Methods： 3T3-L1 preadipocyte was induced by a culture solution containing insulin, isobutyo-menthyl-xanthine, and dexamethasone to mature lipocyte, and it was divided into six groups： the control group （normal cells）, the model group （untreated model cells）, and the four drug treatment group exposed to dimethyl biguanide （Met group）, high- dose pueradn （PueH group）, low-dose puerarin （PueL group）, and propylene glycol （PG group）, respectively. Mature lipocytes in various groups, except those in the normal group, were established into insulin resistance model by FFA induction and treated respectively with corresponding drugs. Peroxisome proliferator-activated receptor- γ （PPAR- γ） mRNA expressions at the fourth, sixth, and eighth day were observed using reverse transcription polymerase chain reaction （RT-PCR）; glucose transportation in various groups were observed by 2-deoxy-[3H]-D-glucose intake method; mRNA expression of Cbl binding protein （CAP） was determined by RT-PCR; and glucose transporter-4 （Glut-4） transposition was detected by immune-fluorescence method. Results： PPAR- γmRNA expression increased gradually, and it showed lower levels at the fourth, sixth, and eighth day in all treatment groups than that in the model group. Glucose transportation determination showed that the transportation in the model group was 2.23 ± 0.63, significantly lower than that in the normal group 5.05 ± 0.66 （P〈0.01）; as compared with the model group, they were significantly higher in the PueH and the PueL groups. In addition, the CAP mRNA expression and membranous distribution of Glut-4 were higher in the two Pue treated groups than those in the model group, respectively. Conclusion： Pue could markedly improve the insulin resistance of 3T3-L1 lipocyte, which is realized possibly by way of inactivating CAP path, promoting Glut-4 transposition to cell membrane to increase the transportation of glucose.展开更多
A 15 Asn,A 17 Pro,A 21 Ala] insulin was synthesized by the Fmoc solid phase synthetic method to study the biological significance of the helix in the C terminal region of A chain of insulin.In order to make this helix...A 15 Asn,A 17 Pro,A 21 Ala] insulin was synthesized by the Fmoc solid phase synthetic method to study the biological significance of the helix in the C terminal region of A chain of insulin.In order to make this helix unable to form,Asn and Pro were utilized to substitute A 15 Gln and A 17 Glu,respectively,according to the Chuo Fasman method.The biological activity assays showed that this insulin analogue held only 10% of the biological activities of native insulin.The results suggest that the loss of the A12 18 helix in A chain leads to a remarkable decrease of biological activities of insulin,and this helix is significant to the three dimensional structure and biological functions of insulin.展开更多
文摘Objective： To explore the molecular mechanism of puerarin （Pue） in improving insulin resistance through observing its effect on the insulin resistance of 3T3-Li lipocyte induced by free fatty acid （FFA）. Methods： 3T3-L1 preadipocyte was induced by a culture solution containing insulin, isobutyo-menthyl-xanthine, and dexamethasone to mature lipocyte, and it was divided into six groups： the control group （normal cells）, the model group （untreated model cells）, and the four drug treatment group exposed to dimethyl biguanide （Met group）, high- dose pueradn （PueH group）, low-dose puerarin （PueL group）, and propylene glycol （PG group）, respectively. Mature lipocytes in various groups, except those in the normal group, were established into insulin resistance model by FFA induction and treated respectively with corresponding drugs. Peroxisome proliferator-activated receptor- γ （PPAR- γ） mRNA expressions at the fourth, sixth, and eighth day were observed using reverse transcription polymerase chain reaction （RT-PCR）; glucose transportation in various groups were observed by 2-deoxy-[3H]-D-glucose intake method; mRNA expression of Cbl binding protein （CAP） was determined by RT-PCR; and glucose transporter-4 （Glut-4） transposition was detected by immune-fluorescence method. Results： PPAR- γmRNA expression increased gradually, and it showed lower levels at the fourth, sixth, and eighth day in all treatment groups than that in the model group. Glucose transportation determination showed that the transportation in the model group was 2.23 ± 0.63, significantly lower than that in the normal group 5.05 ± 0.66 （P〈0.01）; as compared with the model group, they were significantly higher in the PueH and the PueL groups. In addition, the CAP mRNA expression and membranous distribution of Glut-4 were higher in the two Pue treated groups than those in the model group, respectively. Conclusion： Pue could markedly improve the insulin resistance of 3T3-L1 lipocyte, which is realized possibly by way of inactivating CAP path, promoting Glut-4 transposition to cell membrane to increase the transportation of glucose.
文摘A 15 Asn,A 17 Pro,A 21 Ala] insulin was synthesized by the Fmoc solid phase synthetic method to study the biological significance of the helix in the C terminal region of A chain of insulin.In order to make this helix unable to form,Asn and Pro were utilized to substitute A 15 Gln and A 17 Glu,respectively,according to the Chuo Fasman method.The biological activity assays showed that this insulin analogue held only 10% of the biological activities of native insulin.The results suggest that the loss of the A12 18 helix in A chain leads to a remarkable decrease of biological activities of insulin,and this helix is significant to the three dimensional structure and biological functions of insulin.
