Impact of fatness, insulin, and gynecological age on luteinizing hormone secretory dynamics in adolescent females

ObjectiveTo study the link between fatness and gonadotropin secretion. Overweight status is linked to polycystic ovary syndrome (PCOS) in adolescents. We postulated that heavier adolescents without symptoms would secrete LH with: [1] increased pulse frequency (LHPF) and [2] exaggerated integrated concentrations (LHAUC).DesignCross-sectional.SettingGeneral clinical research center.Patient(s)Eighty-seven postmenarcheal cyclic adolescents from lean to overweight recruited during the follicular phase.Intervention(s)Luteinizing hormone sampling: [1] every 10 minutes/24 hours; [2] at 20-minute intervals after a GnRH challenge.Main Outcome Measure(s)The LHPF and LHAUC (calculated by the CLUSTER algorithm). Hormonal and metabolic covariates included percent body fat (PercentBF), insulin-like growth factor-I (IGF-I), fasting insulin, and the insulin resistance index HOMA-IR. The SAS software was used for analyses.Result(s)The PercentBF and younger gynecological age predicted faster LHPF. Fatness was negatively linked to LHAUC, which was best predicted by PercentBF and IGF-1 in multivariate modeling (R2 = 0.25). The PercentBF and insulin predicted a lower 20-minute LH response to GnRH.Conclusion(s)[1] Higher adiposity and younger gynecological age predict rapid LHPF. [2] The early years after menarche represent a vulnerable window for an exaggerated LHPF with weight gain. [3] In healthy adolescents, higher adiposity is linked to lower LHAUC, thereby preserving pituitary stores.