MHPG circadian rhythmicity in blood of healthy subjects.
An earlier study showed that plasma concentrations of total 3-methoxy-4-hydroxyphenylglycol (MHPG), the major metabolite of norepinephrine, display a circadian rhythm in 6 male healthy subjects. In the previous study, the period of the rhythm was not fixed to 24 h thereby undermining the reliability of the cosinor parameter estimates. The present study extends the findings to a larger group of 12 clinically healthy male volunteers. Plasma total MHPG concentrations were determined every 3h for one full day. The data were fitted to a cosinor model fixing the period of the putative MHPG rhythm at 24 h. Several estimation techniques were utilized including Fourier analysis and time domain analysis with 4 variations. It is concluded that a circadian rhythm indeed characterizes MHPG blood concentrations. The concordance among the various parameter estimates is discussed.
Department of Psychiatry, Case Western Reserve University, Cleveland, Ohio.
M
M
Marler
A
A
Halaris
J E
JE
Piletz
D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005583:Fourier Analysis; D006018:Glycols / Q000097:blood*; D006801:Humans; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000097:blood*; D008954:Models, Biological; D015233:Models, Statistical; D012016:Reference Values
D006018:Glycols; D008734:Methoxyhydroxyphenylglycol