Differences in the circadian rhythm parameters of urinary free epinephrine, norepinephrine and dopamine between children and elderly subjects.

The circadian rhythm in the urinary excretion of free epinephrine, norepinephrine and dopamine was studied in 60 elderly men and 83 women, 77 +/- 8 years of age, in a total of 260 24-hour profiles and in 63 boys and 81 girls, 11 +/- 1.5 years of age, in 144 24-hour profiles. The circadian mesor of all these compounds was increased in the children over that in the elderly subjects while the acrophase remained unchanged in spite of a phase shift of the acrophase of the urine excretion of the elderly in the night hours. The differences in functional state of the sympathetic and adreno-medullary function (and/or response) between children and elderly subjects may have clinical implications.