Analysis Of Plasma Obestatin And Ghrelin Level And Related Factors In Obese Children

Objective:Dynamic determination of Plasma Obestatin and Ghrelin concentration, Ghrelin / Obestatin ratio in obese children before and after glucose load to investigated the effects of glucose load in plasma Obestatin and Ghrelin concentration,and studied their relationships between body parameters,glucose, lipids,insulin and insulin resistance in obese children.Whether plasma Obestatin concentration,Ghrelin concentration,Ghrelin / Obestatin ratio in obese children were influenced by gender or pubertal stage.To explore the mechanism of Obestatin, Ghrelin in the course of obesity development.Methods:25 obese and 25 normal control subjects,then according to Tanner stage divided each group into prepubescence team(Tannerâ… ) and adolescence team (Tannerâ…¡-â…¢).All subjects measured the body parameters,obese subject was measured.Fasting lipoid oral glucose tolerance test,insulin release test meanwhile Obestatin and Ghrelin were measured at 0,1h and 2h following OGTT.Normal control group only measured fasting lipoid,glucose,insulin Obestatin and Ghrelin.Calculated Homeostasis model assessment of insulin resistance(HOMA-IR), homeostasis model assessment ofβcell(HOMA-β),whole body insulin sensitivity index(WBISI).Plasma Obestatin and Ghrelin levels were measured by radioimmunoassay.Result:1.(1) In obese group plasma Obestatin,Ghrelin levels were lower than the control group(p＜0.01),but There were no significant differences in the ratio of fasting Ghrelin/Obestatin ratio between obese and normalweight controls.(2)Fasting Obestatin concentration in all subjects was negatively significant correlated with body weight,waist circumference,BMI,triglycerides,homeostasis model assessment of insulin resistance.Fasting Ghrelin concentration was negatively significant correlated with body weight,waist circumference,BMI,total cholesterol,triglycerides,low density lipoprotein,homeostasis model assessment of insulin resistance,homeostasis model assessment ofβcell,was positively significant correlated with high density lipoprotein.(3) Multiple linear regression analysis was used to determine the correlation coefficient for Obestatin Ghrelin and Ghrelin/Obestatin ratio.For Obestatin,Only HOMA-IR was enter the regression equation R²=0.183,the standard partial coefficient was -0.428(p＜0.01),the regression equation was Obestatin=171.122-25.668ln^HOMA-IR.For Ghrelin,Only BMI was enter the equation R²=0.242,the standard partial coefficient was-0.492(p＜0.01) the regression equation was Ghrelin=505.245-323.361ln^lnBMI.For Ghrelin/Obestatin ratio,only HOMA-βwas enter the equation R²=0.182,the standard partial coefficient was 0.427(p＜0.01),the regression equation was In^{Ghrelin/Obestatin}=1.257-0.205ln^HOMA-β.2.(1)Glucose and insulin concentrations increased after glucose load,and among fasting and 1h,2h after glucose load three time points glucose concentrations reached the maximum value 1h after glucose load,as well as insulin concentrations. In contrast with glucose,Obestatin and Ghrelin concentrations decreased after glucose load.Obestatin concentrations display a pattern that it declined and then increased,and Ghrelin concentrations declined along time.S-N-K comparison found that fasting plasma Ghrelin concentrations significantly higher than 2h afrer glucose load(p＜0.05);Ghrelin/Obestatin ratio displayed an opposite Obestatin pattern that it increased and then descend.They had different change patterns.(2)Obestatin and Ghrelin were significant correlated among the three time points,respectively.3.(1) The boys in obesity group prepubescence team,whose Obestatin,Ghrelin,Ghrelin1h,Ghrelin2h were higher than adolescence boys(p＜0.05);The girls that in obesity group prepubescence team Obestatin 2h,fasting Ghrelin,Ghrelin1h, Ghrelin2h were higher than adolescence obesity girls(p＜0.05).(2)In control group plasma Obestatin,Ghrelin,Ghrelin / Obestatin ratio,Homeostasis model assessment of insulin resistance(HOMA-IR),homeostasis model assessment ofβcell(HOMA-β),were no statistically significant difference between the same gender in different pubertal stages subjects.Plasma Obestatin,Ghrelin,Ghrelin / Obestatin, Homeostasis model assessment of insulin resistance(HOMA-IR),homeostasis model assessment ofβcell(HOMA-β),were no statistically significant differences in different gender the same pubertal stages too.Conclusion:1.Plasma Ghrelin and Obestatin concentrations were lower in obese group,and their relationships between body parameters and biochemical indicators, support Obestatin and Ghrelin play a role in the development process of obesity in childhood,and concerned with glucose,insulin and insulin resistance.2.Plasma Ghrelin and Obestatin concentrations after glucose load were lower than fasting and followed changes,suggest that they may regulat by glucose and insulin.3.Obese children in prepubescence team had lower Ghrelin and Obestatin concentrations no matter boys or girls.Plasma Obestatin and Ghrelin concentrations were different in different stages of puberty in obese children.it may caused by a series of hormone changes in adolescence.