title: Characteristics of luteinizing hormone secretion in younger versus older premenopausal women.
abstract: OBJECTIVE
  The objectives of this study were to document specific attributes of pulsatile luteinizing hormone secretion in middle-aged women before discernible alterations in their menstrual cycles and to compare the results to corresponding data obtained in younger women.
  
  
  METHODS
  After documenting normal cycle length, biphasic basal body temperatures, and normal midluteal progesterone in younger and middle-aged women during an initial cycle, daily blood samples and samples withdrawn at 10-minute intervals for 8 hours during the midfollicular phase were obtained during a subsequent cycle.
  
  
  RESULTS
  Assessment of luteinizing hormone pulses with the pulse detection algorithm Cluster demonstrated a prolonged interpulse interval and increased pulse width in the older women. Assessment of luteinizing hormone secretory bursts and half-life with the deconvolution analysis procedure demonstrated a prolonged interburst interval and half-life in the older women. Appraisal of approximate entropy revealed greater orderliness of luteinizing hormone release in the older women.
  
  
  CONCLUSIONS
  Middle-aged women exhibit alterations in hypothalamic-pituitary function that may account in part for age-related changes in reproductive potential.
authors.affiliation: Department of Obstetrics and Gynecology, Medical College of Virginia of Virginia Commonwealth University, Richmond 23298, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Matt
authors.forename: S W
authors.initials: SW
authors.lastname: Kauma
authors.forename: S M
authors.initials: SM
authors.lastname: Pincus
authors.forename: J D
authors.initials: JD
authors.lastname: Veldhuis
authors.forename: W S
authors.initials: WS
authors.lastname: Evans
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology*; D016000:Cluster Analysis; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008875:Middle Aged; D017697:Premenopause / Q000502:physiology*; D011374:Progesterone / Q000097:blood
chemical_list: D011374:Progesterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone