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Gender‐related differences in urinary 6‐sulfatoxymelatonin levels in obese pubertal individuals
Author(s) -
Fideleff Hugo L.,
Boquete Hugo,
Fideleff Gabriel,
Albornoz Liliana,
Lloret Santiago Pérez,
Suarez Martha,
Esquifino Ana I.,
Honfi Margarita,
Cardinali Daniel P.
Publication year - 2006
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.2005.00301.x
Subject(s) - urinary system , melatonin , obesity , medicine , endocrinology , demography , psychology , developmental psychology , sociology
The objective of this study was to measure the urinary excretion of the main melatonin metabolite 6‐sulfatoxymelatonin in obese and normal weight (wt) boys and girls. The study included 94 subjects, aged 4–15.7 yr (50 obese and 44 normal wt; 48 boys) classified as: mid‐childhood (4–7.99 yr), late‐childhood (8–12 yr) and pubertal (10.1–15.7 yr, Tanner II–IV). Normal wt subjects were children with a body mass index (BMI) between the 25th and 75th percentiles, and the group of obese subjects included children whose BMI was above the 97th percentile. A 24‐hr urine sample was collected during two intervals: (i) 18:00–08:00 hr, and (ii) 08:00–18:00 hr. Analysis of urinary 6‐sulfatoxymelatonin levels was performed by radioimmunoassay. Excretion of 6‐sulfatoxymelatonin was expressed as: (i) total amount excreted ( μ g); (ii) μ g excreted per time interval, nocturnal or diurnal; and (iii) the difference between nocturnal and diurnal samples ( μ g, estimated amplitude). A factorial analysis of variance indicated that nocturnal 6‐sulfatoxymelatonin excretion and amplitude were significantly higher in the obese individuals. A significant interaction ‘BMI × age’ was detected, i.e. the effect of BMI was significant in the pubertal group only. Total, nocturnal and diurnal 6‐sulfatoxymelatonin excretion was significantly higher in girls. The increase in 6‐sulfatoxymelatonin excretion found in obesity occurred only in boys and at the pubertal age. To what extent this increase in melatonin production contributes to a delayed puberty in some pubertal obese males remains to be established.