Assessment
of the relationship between circadian variations of salivary
melatonin levels and type I collagen metabolism in postmenopausal
obese women
by Zofia
Ostrowska, Beata Kos-Kudla, Bogdan Marek, Elzbieta Swietochowska
& Janusz GÛrski
Keywords:
melatonin, metabolism
of type I collagen, postmenopausal obese women
Submitted:
January 21, 2001
Accepted: February 06, 2001
Abstract:
BACKGROUND:
Few experimental and clinical studies show that melatonin
(MEL) can play a significant part to modulate circadian bone
metabolism. On this basis it was suggested that MEL secretion
which altered during 24-h in obese women could be of importance
to regulate bony mass defect after menopause.
OBJECTIVE: The aim of the study was to prove if there were
any connection between changes in 24-h profile of serum MEL
levels and circadian metabolism of type I collagen in postmenopausal
women with visceral obesity.
METHODS: The relationship of 24-h profile of salivary MEL
and circadian metabolism of type I collagen (as assessed by
measuring saliva concentrations of carboxyterminal propeptide
of type I procollagen - PICP and cross-linked carboxyterminal
telopeptide of type I collagen - ICTP) was investigated in
26 women with visceral obesity (33.5 < BMI < 42.1 kg/m2)
and 18 healthy volunteers with correct body mass (21 <
BMI < 24.5 kg/m2; 0.73 < WHR < 0.76). The specimens
were collected at subjects’ home at 3 h intervals during
a 24 h span. The age range of all subjects was 52–60
years.
RESULTS: In all the obese women studied a tendency to suppress
circadian levels of tested biochemical markers of bone metabolism
was observed (especially regarding ICTP); those alterations
were accompanied by substantial increment in MEL concentrations
during the day. Significant and negative correlation was found
between values of acrophase MEL and PICP rhythms and both
amplitude and acrophase of MEL and ICTP rhythms.
CONCLUSION: Our results confirm hypothesis that alterations
in MEL concentrations might have a protective effect against
postmenopausal loss of bone mass.
