title: Pineal volume and circadian melatonin profile in healthy volunteers: an interdisciplinary approach.
abstract: OBJECTIVE
  To correlate pineal parenchyma volume (PP) to circadian melatonin profiles and to determine the 24-hour melatonin per volume of pineal tissue (MLPV). Furthermore, we compared melatonin profiles of cystic and solid glands.
  
  
  METHODS
  In 15 healthy male subjects (20-27 years) the PP was determined using high-resolution magnetic resonance imaging (trueFISP, isotropic voxel: 0.8 mm(3)). Melatonin plasma concentrations (MC) were determined every 2 hours for 24 hours.
  
  
  RESULTS
  Mean PP was 125 +/- 54 mm(3). PP correlated linearly to maximum MC and to 24-hour melatonin (r = 0.61 and r = 0.64, P < 0.05) but not to minimum MC. The 24-hour melatonin was 653 +/- 242.6 pg/mL, MLPV was 5.8 +/- 2.3 pg/mL*ml(-1). Nine pineal glands were solid and six were cystic. PP of solid glands showed higher linear correlations to maximum melatonin, to 24-hour melatonin, and to the slope of the melatonin increase of the curve (P < 0.05).
  
  
  CONCLUSIONS
  PP correlates linearly to melatonin plasma concentrations in humans. MLPV displays similar interindividual differences as 24-hour melatonin. PP of solid glands show better correlation to melatonin profiles than cystic.
authors.affiliation: Department of Neuroradiology, Medical Faculty Mannheim of the University of Heidelberg, Germany. Ingo.noelte@rad.ma.uni-heidelberg.de
authors.forename: Ingo
authors.initials: I
authors.lastname: Nölte
authors.forename: Ann-Theres
authors.initials: AT
authors.lastname: Lütkhoff
authors.forename: Boris A
authors.initials: BA
authors.lastname: Stuck
authors.forename: Björn
authors.initials: B
authors.lastname: Lemmer
authors.forename: Michael
authors.initials: M
authors.lastname: Schredl
authors.forename: Peter
authors.initials: P
authors.lastname: Findeisen
authors.forename: Christoph
authors.initials: C
authors.lastname: Groden
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008550:Melatonin / Q000097:blood*; D010870:Pineal Gland / Q000033:anatomy & histology*; D012016:Reference Values; D055815:Young Adult
chemical_list: D008550:Melatonin