title: Acute effects of testosterone infusion on the serum luteinizing hormone profile in eumenorrheic and polycystic ovary syndrome adolescents.
abstract: BACKGROUND
  Little is known about the neuroendocrine effects of androgens on the GnRH-LH unit in females.
  
  
  OBJECTIVE
  Our objective was to evaluate androgen negative feedback on the GnRH-LH axis in eumenorrheic and polycystic ovary syndrome (PCOS) adolescents.
  
  
  METHODS
  We conducted a prospective, longitudinal, randomized, double-blind study at a pediatric endocrinology clinical research center.
  
  
  METHODS
  Seven nonobese PCOS adolescents and seven matched controls (C) were studied in the early follicular phase of three consecutive menstrual cycles or in three consecutive months.
  
  
  METHODS
  Pulsatile LH release was determined during saline [baseline (B)] and constant testosterone (T) infusions: low dose (T-LD) 0.75 and high dose (T-HD) 2.5 mg/12 h iv. Blood samples were drawn every 20 min overnight.
  
  
  METHODS
  LH (immunofluorometric assay) and T (electrochemiluminescence immunoassay) were determined at B, and during both T-LD and T-HD. LH profiles were analyzed by deconvolution and approximate entropy analyses.
  
  
  RESULTS
  On T-LD, C and PCOS serum T levels increased 2- to 3-fold vs. B. On T-HD, T values doubled in both groups vs. T-LD. Controls on T-LD had greater 12-h pulsatile LH secretion rate (P < 0.05 vs. B) and on T-HD had lower mean, pulsatile, basal LH release and LH approximate entropy (vs. B, P < 0.05). PCOS did not respond to T-LD. High-dose T did not alter mean LH in PCOS but increased pulsatile and reduced basal LH secretion.
  
  
  CONCLUSIONS
  PCOS adolescents have impaired suppression of pulsatile LH secretion rate consistent with reduced androgen negative feedback. Attenuation of T feedback in nonobese adolescents with PCOS extends the pathophysiology of this syndrome.
authors: División de Endocrinología, Centro de Investigaciones Endocrinológicas, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires C1425EFD, Argentina. gropelato@cedie.org.ar
authors: María Gabriela
authors: MG
authors: Ropelato
authors: María Cecilia García
authors: MC
authors: Rudaz
authors: María Eugenia
authors: ME
authors: Escobar
authors: Sonia Viviana
authors: SV
authors: Bengolea
authors: María Luján
authors: ML
authors: Calcagno
authors: Johannes D
authors: JD
authors: Veldhuis
authors: Marta
authors: M
authors: Barontini
mesh_terms: D000293:Adolescent; D004311:Double-Blind Method; D025461:Feedback, Physiological; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D007986:Luteinizing Hormone / Q000097:blood* / Q000378:metabolism; D011085:Polycystic Ovary Syndrome / Q000378:metabolism*; D011446:Prospective Studies; D013739:Testosterone / Q000097:blood / Q000494:pharmacology*
chemical_list: D013739:Testosterone; D007986:Luteinizing Hormone