Pineal volume and circadian melatonin profile in healthy volunteers: an interdisciplinary approach.
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.
Nölte
Ingo
I
Department of Neuroradiology, Medical Faculty Mannheim of the University of Heidelberg, Germany. Ingo.noelte@rad.ma.uni-heidelberg.de
Lütkhoff
Ann-Theres
AT
Stuck
Boris A
BA
Lemmer
Björn
B
Schredl
Michael
M
Findeisen
Peter
P
Groden
Christoph
C
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
D008550:Melatonin