Aim To examine the association between serum leptin and microalbuminuria(MA),body mass index(BMI),fasting serum insulin(FINS),homeostasis model assessment insulin resistance(HOMA-IR)and evaluate function of the correlation in mechanism of hypertension with impaired glucose tolerance(IGT).Methods This study included 198 hypertensives and 47 healthy subjects.Hypertensives were divided into 3 groups according to their glucose tolerance:NGT,IGT and DM groups.Serum leptin,urinary albumin excretion rate(UAER),FINS,serum beta2-microglobulin(β₂-MG)and urinary β₂-MG concentrations were determined by radioimmunoassay.Results Baseline clinical characteristics of patients and the controls showed that serum leptin concentrations in females were significantly higher as compared with males(p<0.001).In IGT group,serum leptin levels and UAER were higher than in control group(13.6±8.0 μg/L vs 3.87±1.48 μg/L and 18.8±12.5 μg/min vs 5.47±2.19 μg/min,p<0.05)and NGT group (13.6±8.0 μg/L vs 6.08±2.03 μg/L and 18.8±12.5 μg/min vs 10.0±5.2 μg/min,p<0.05),but lower than in DM group(13.6±8.0 μg/L vs 16.6±8.7 μg/L and 18.8±12.5 μg/min vs 30.5±12.3 μg/min,p<0.05).Serum leptin concentrations of obese patients were higher than non-obese ones(15.1±9.0 μg/L vs 11.6±6.0 μg/L,p<0.05).Serum leptin levels of patients with microalbuminuria were significantly higher than subjects with normoalbuminuria(16.0±9.9μg/L vs 11.7±5.6 μg/L,p<0.05).After adjustment for sex and the degree of body fat mass,leptin was positively correlated with UAER(r=0.543,p<0.001),urinary β₂-MG(r=0.337,p<0.01),serum β₂-MG(r=0.230,p<0.05),pulse pressure(r=0.364,p<0.001),HOMA-IR(r=0.325,p<0.01),FINS (r=0.302,p<0.01)and systolic blood pressure(r=0.290,p<0.01).Multiple backward regression analysis showed sex,UAER,HOMA-IRand pulse pressure were significantlyrelatedtoleptin.Conclusions Sexand BMI arethe most significantdeterminants of serumleptin concentrations.The development of hypertension withIGTis decided by interrelation of many fac-tors,furthermore,renal function might have been damagedinthis stage.