Circadian and other variation in epinephrine and norepinephrine among several human populations, including healthy blinded and sighted subjects and patients with leprosy.

Urinary levels of epinephrine and norepinephrine were studied in three populations: presumably healthy young men who were studied twice, 8 years apart, and in the same month to avoid seasonal influences; blinded but otherwise healthy males and females; and patients with leprosy. Determinations of epinephrine and norepinephrine were done on urine samples collected at 3-hr intervals for 72 hr from the first two groups and for 10 days from patients with leprosy. The same chemist, method, and protocol were used in all studies. In one study of the group of healthy young men, the effect of meal timing and fasting on the rhythms was investigated. From these studies several generalizations can be made. Highly statistically significant population circadian rhythms characterize both epinephrine and norepinephrine in all three groups. In general, the rhythm in norepinephrine was "noisier" than that in epinephrine; in the blind subjects, both variables were characterized by noisier rhythms than in the sighted. The overall levels of epinephrine were much higher in blind than in sighted subjects. The overall levels of norepinephrine were much higher in blind males than in blind females. In the studies done with the group of healthy young men, the overall levels of epinephrine and norepinephrine increased significantly over a 10-year period. The amplitude of the rhythm also increased significantly with time. The average age of the group was 27 years at the time of the first study and 40 years at the time of the second. The patients with leprosy also showed strong circadian variation in both epinephrine and norepinephrine, but, because many of the subjects were on medication, comparisons with the other groups are questionable. In general the data raise some questions about, but do not refute, the commonly held view that the amplitude and mesor of the circadian rhythm in epinephrine decrease with age. Additional work is needed to resolve this question completely.