SAT-LB047 Circulating IGF-1, MKRN3, and Kisspeptin in Girls during the Onset of Puberty

Objective To evaluate the differences of serum IGF-1, MKRN3 and kisspeptin in girls with central precocious puberty, rapidly progressive puberty, premature thelarche and control group, explore their roles in the initiation of puberty, and assess the diagnostic value of IGF-1 in puberty initiation. Methods The girls with the chief complaint of development of secondary sexual characteristics from the outpatient department were recruited, at the same time, the girls with normal puberty were recruited as normal controls. Informed consents were signed. The levels of MKRN3 and kisspeptin were measured using ELISA kits, and the level of IGF-1 was measured using chemiluminescence immunoassay kit. Results 1) MKRN3 There were no difference in the level of MKRN3 among the four groups (P=0.244). Combining the above four groups into HPGA initiated group and HPGA non-initiated group, the difference of MKRN3 level between the above two groups were not statistically significant (P=0.435). Over 10 years of age, the MKRN3 level in the HPGA initiated group was lower than that of the HPGA non-initiated group with significant differences(P=0.006). The negative correlation between MKRN3 and estradiol, LH level appeared only after 10 years (r=-0.464, P=0.034, r=-0.473, P=0.017). 2) Kisspeptin There were statistically differences in the level of kisspeptin among the four groups(P=0.003). The older the bone age at the first visit, the higher the kisspeptin level in HPGA initiation patients. Positive correlation was existed between kisspeptin level and height, weight, bone age, basal LH level, basal FSH level, peak LH level, and the ratio of peak LH and FSH level(P<0.05). 3) IGF-1 There were statistically differences in the level of IGF-1 among the four groups of CPP, RPP, PT and control groups(P=0.000). And the level of IGF-1 in the HPGA initiated group was significantly higher than that in the HPGA non-initiated group among different age levels(P=0.011, P=0.004, P=0.004). Positive correlation was also existed between IGF-1 level and some indicators(P<0.05). IGF-1 had certain diagnostic value for the identification of HPGA initiation, the area under the curve(AUC) of ROC curve was 0.833, at IGF-1 level of 304ng/ml, the Youden index reached the peak value (0.661), and the sensitivity and specificity were 0.750 and 0.911 respectively. At different age levels, The AUC of IGF-1 were 0.708, 0.866, 0.958, indicating that IGF-1was still useful among different age levels. Conclusions IGF-1, MKRN3 and kisspeptin all play important roles in the process of puberty initiation. MKRN3 acts as an inhibitory factor on GnRH whereas IGF-1 and kisspeptin are the stimulatory factors. In addition, IGF-1 has certain diagnostic value in the differential diagnosis of puberty initiation at different age levels. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.