title: Impact of fatness, insulin, and gynecological age on luteinizing hormone secretory dynamics in adolescent females.
abstract: OBJECTIVE
  To 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).
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  General clinical research center.
  
  
  METHODS
  Eighty-seven postmenarcheal cyclic adolescents from lean to overweight recruited during the follicular phase.
  
  
  METHODS
  Luteinizing hormone sampling: [1] every 10 minutes/24 hours; [2] at 20-minute intervals after a GnRH challenge.
  
  
  METHODS
  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.
  
  
  RESULTS
  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 (R(2) = 0.25). The PercentBF and insulin predicted a lower 20-minute LH response to GnRH.
  
  
  CONCLUSIONS
  [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.
authors.affiliation: Department of Pediatrics, University of Michigan, Ann Arbor, Michigan 48019-0718, USA. jzkv@umich.edu
authors.forename: Josephine Z
authors.initials: JZ
authors.lastname: Kasa-Vubu
authors.forename: Vandana
authors.initials: V
authors.lastname: Jain
authors.forename: Kathy
authors.initials: K
authors.lastname: Welch
mesh_terms: D000273:Adipose Tissue / Q000098:blood supply / Q000378:metabolism*; D000293:Adolescent; D000367:Age Factors; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D050177:Overweight / Q000097:blood; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013851:Thinness / Q000097:blood; D055815:Young Adult
chemical_list: D007328:Insulin; D007986:Luteinizing Hormone