| Objectives The aim was to study the fasting and postprandial serum leptin levels by oral high fat load test in people with different body mass index(BMI),and the influencing factors of serum leptin were investigated.Methods Volunteers aged between 25 and 65 years were recruited from the outpatient department of endocrinology,Hebei General Hospital.Routine physical examination and oral glucose tolerance test(OGTT)were performed.A total of 145 patients who met the inclusion criteria signed informed consent and took oral high fat load test.After a week of normal diet washout and 8-hours fasting,all subjects participated in oral fat tolerance test(OFTT).Venous blood samples of fasting and 2,4,6 hours after the high-fat meal were taken respectively,then biochemical indexes and leptin were determined.The subjects were assigned into three groups according to BMI: 1)control group(CON),18.5≤BMI<24;2)overweight group(OW),24≤BMI<28;3)obesity group(OB),BMI≥28.SPSS26.0software was used for statistical analysis.Results 1 Comparison of general conditions and fasting lipid indexes: 1)There were no significant differences in age,sex among three groups(P>0.05).The three groups showed statistical differences(P<0.05)in body weight,waist circumference,BMI,fasting blood glucose(FBG)and fasting insulin(FINS).The body weight,waist circumference,BMI and FINS of OW group and OB group were higher than CON group(P<0.05).FBG of OW group was higher than CON group(P<0.05).Body weight,waist circumference,BMI and FINS of OB group were higher than those of OW group(P<0.05).2)Compared with CON group,triglyceride(TG)levels of OW group and OB group were higher(P<0.05),but no statistical difference was observed between OW group and OB group(P>0.05).There were no significant differences in fasting total cholesterol(TC),low density lipoprotein cholesterol(LDL-C)and apolipoprotein B(Apo B)among three groups(P>0.05).Compared with OW and CON group,the level of fasting high density lipoprotein cholesterol(HDL-C)and apolipoprotein A1(Apo A1)of OB group were lower(P<0.05),but these parameters showed no statistical difference between OW and CON group(P>0.05).The level of fasting non-HDL-C in OB group was higher than that in CON group(P<0.05),while there was no statistical difference between OW and OB group(P>0.05).2The TG level of three groups increased with time after meal.TG of CON group reached the peak at 2h.In contrast,TG of OW group reached the peak at 4 h,then decreased gradually,and TG level at 6h were still higher than the fasting level(P<0.001).The TG level of OB group reached the peak at 6h.The TG level at 2h,4h and 6h in three groups were all higher than fasting TG levels(P<0.001).3 Fasting leptin levels in three groups were statistically different(P<0.001).The lowest level of fasting leptin was observed in CON group and the highest was found in OB group.The level of leptin increased after meal in all three groups.In CON and OW groups,the leptin level at 2h,4h and 6h was significantly higher than the corresponding fasting level.In the OB group,there was no statistical difference between fasting leptin level and leptin levels at 2h,4h and 6h.4Correlation analysis: Fasting leptin level was significantly positively correlated with BMI(r=0.725,P<0.001),waist circumference(r=0.465,P<0.001),fasting TG(r=0.188,P=0.024),fasting insulin(r=0.542,P<0.001),and negatively correlated with fasting HDLC(r=-0.244,P=0.003).Conclusions 1 The serum leptin level increases significantly with BMI.2 When the leptin secretion reaches a certain level in obese people,the leptin secretion no longer increases with the increase of serum TG.Figure 2;Table 5;Reference 186... |
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