title: Leptin levels and luteinizing hormone pulsatility in normal cycling women and their relationship to daily changes in metabolic rate.
abstract: OBJECTIVE
  To determine whether leptin and LH secretion in normal women is related to changes in metabolic rate.
  
  
  METHODS
  Academic medical center. PATIENT(S) AND DESIGN: Ten young women with normal weight and menses were studied during the early follicular phase. Leptin and LH levels were sampled every 15 minutes over a 24-hour period. Metabolic rate was frequently sampled using indirect calorimetry. Luteinizing hormone pulsatility was analyzed using a Cluster Program analysis.
  
  
  METHODS
  None.
  
  
  METHODS
  Leptin, LH, and metabolic rate levels.
  
  
  RESULTS
  All subjects demonstrated a diurnal leptin curve. Luteinizing hormone pulses were increased in amplitude and slower after the leptin peak. The average (+/-SE) number of LH pulses per 6 hours slowed from 4.30 +/- 0.42 to 3.00 +/- 0.42 pulses after the leptin peak, whereas pulse amplitude increased from 1.64 +/- 0.26 to 2.51 +/- 0.42 mIU/mL after the leptin peak. The LH interpulse interval increased from 85.1 +/- 3.64 minutes to 108.8 +/- 10.26 minutes after the leptin peak. Metabolic rate began to drop approximately 4-6 hours before leptin levels peaked, going from 1.66 +/- 0.24 to 1.15 +/- 0.04 kcal/min after the leptin peak.
  
  
  CONCLUSIONS
  There is a significant association between the timing of the leptin peak, the nightly slowing of LH pulses, and the fall in metabolic rate, suggesting a metabolic cycle in normal individuals.
authors.affiliation: Department of Obstetrics and Gynecology, Columbia College of Physicians and Surgeons, New York, New York 10032, USA. rf2013@columbia.edu
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Fenichel
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Dominguez
authors.forename: Laurel
authors.initials: L
authors.lastname: Mayer
authors.forename: B Timothy
authors.initials: BT
authors.lastname: Walsh
authors.forename: Carol
authors.initials: C
authors.lastname: Boozer
authors.forename: Michelle P
authors.initials: MP
authors.lastname: Warren
mesh_terms: D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D007986:Luteinizing Hormone / Q000097:blood*; D008597:Menstrual Cycle / Q000097:blood*; D008875:Middle Aged
chemical_list: D020738:Leptin; D007986:Luteinizing Hormone