Abstract： Objective This study was designed to investigate the correlationship between plasma metastin and pathogenesis of adolescent women with polycystic ovary syndrome(PCOS).Methods From Jan 2006 to Jun.2006.42 PCOS patients including 19 adolescent women and 23 adults with syndrome were treated in Second Affiliated Hospital of Sun Yat-Sen University.According to the range of age,those patients were divided into 19 cases in adolascent group(≤19 years)and 23 cases in aduh group(＞19 years).Meanwhile,20 adolescent women were matched as controls.Blood samples were collected between day 1 and day 5 of a spontaneous bleeding episode in the PCOS groups and a menstrual cycle of the controls.The Jevels of luteinizing hormone(LH)，follicle-stimulating hormone(FSH)，testosterone(T)，free T(FT)，dehydroepiandrosterone sulfate(DHEAS)，sex hormone-binding globulin(SHBG)，insulin，glucose，and metastin were detected from day 1 to day 5 of spontaneous bleeding or withdrawal bleeding by progesterone.On the next day,oral glucose tolerance test(75 g)and insulin release test were performed on those above patients and controls.The area under carve(AUC),the ratio of fasting blood glucose to insulin(GIR)and homeostasis model assessment insulin resistance jndex ( HOMA-IR)were calculated.Results (1)The level of hormone:the level of LH was in(12±7)U/L in adult group and(12±8)U/L in adolescent PCOS group，which were significantly higher than(6±4)U/L in controls(P＜0.05).The level of FT was(2.3±1.2)pmol/L in adult group，which was significantly higher than(1.3±0.8)pmol/L in adolescent group and(1.1±0.5)pmol/L in control roup(P＜0.05).It was observed that the level of(3.1±2.7)μmol/L in adolescent group was significantly lower than(6.3±2.7)μmol/L in control group(P＜0.05).Meanwhile,the level of FAI of 5.6±4.1 in adult group was significantly higher than 3.0±1.3 in control group(P＜0.05).No significant difference in FSH，T and SHBG levels among three groups were observed (P＞0.05).(2)Metastin and metabolism:Both the levels of fasting blood insulin,2-hour insulin and AUC of insulin were(13±7)mU/L，(88±59)mU/L and(133±80)mU·L-1·min-1 in adolescent group，which were significantly higher than(7±3)mU/L，(57±29)mU/L and(82±34)mU·L-1·min-1 in control group.The fasting blood insulin of(13±7)mU/L in adolescent group was significantly higher than (9±5)mU/L in adult group.The level of fasting blood glucose and 2-hour glucose were(5.01±0.44)mmol/L and(6.48±1.16)mmol/L in adult group，which were significantly higher than(4.68±0.29)mmol/L and(5.44±0.83)mmol/L in control group and(4.67±0.30)mmol/L and(5.93±1.44)mmol/L in adolescent group.The glucose AUC of(9.99±1.85)mmol·L-1·min-1 in adult group was significantly higher than(8.42±1.53)mmol·L-1·min-1 in control group(P＜0.05).HOMA-IR of 2.6±2.0 in adolescent group was significantly higher than 1.4±0.7 in control group.GIR of 10±8 in adolescent group was significantly lower than 16±10 in control group(P＜0.05).The metastin level of (0.25±0.19)pmol/L in adolescent group and(0.29±0.29)pmol/L in adult group were all significantly higher than(0.18±0.23)pmol/L in control group(PPh glucose were observed(r=0.256，0.286 and 0.267.P=0.044.0.025 and 0.043).Conclusions The expression of metastin in adolescent PCOS women was significantly higher that of normal adolescent women The increased level of metastin might be associated with pathogenesis of adolescent women with PCOS.