Circadian Rhythms in the Urinary Excretion of Metals and Organic Substances in “Healthy” Men

Abstract

Circadian rhythms in the urinary excretion of metals and organic substances were examined in ten "healthy" men under conditions of water loading and restriction. Four characteristic rhythms were observed: (1) decreased excretion during the night for lead and urinary flow rate; (2) decreased excretion of hippuric acid, delta-aminolevulinic acid, coproporphyrin, creatinine, and total urinary solutes during the night and morning hours; (3) increased excretion of mercury and zinc during the morning hours; and (4) no significant variation for copper. Excretion of lead, hippuric acid, delta-aminolevulinic acid, and total urinary solutes was significantly correlated with urinary flow rate and creatinine excretion, which suggested that their circadian rhythms were the consequence of reduced glomerular filtration and increased reabsorption by the distal tubule and collecting duct during the night and morning hours. Similarly, it was suggested that the mercury and zinc rhythms resulted partly from increased reabsorption during the night hours; the coproporphyrin rhythm reflected reduced glomerular filtration of coproporphyrinogen during the night and morning hours.

Circadian Rhythms of Seven Heavy Metals in Plasma, Erythrocytes and Urine in Men. Observation in Metal Workers.

“…However, when the two groups were combined in the analysis, the urinary excretion of Zn was significantly higher during morning hours than during each of other three time periods (p<0.05). The increase in urinary Zn excretion during morning hours has been found by Bhattacharya 5) and by us 8,9) . Pb, Cd and Cu in plasma decreased during the night hours, resembling their urinary rhythms; the rhythm of Hg in erythrocytes was similar to its urinary rhythm, showing the lowest level in the afternoon (Figs.…”

“…variations observed within a day, in human subjects have been elucidated by many workers [1][2][3][4][5][6][7][8][9][10] . On the other hand, the rhythms of these heavy metals in blood (plasma and erythrocytes) have been reported only for Zn and Cu 2,6,[11][12][13][14][15] .…”

Subclinical cervico‐spino‐bulbar effects of lead: A study of short‐latency somatosensory evoked potentials in workers exposed to lead, zinc, and copper

“…Blood samples were collected just before the electrophysiological studies and the start of the 24-hour urine collection. The activity of the intraerythrocytic enzyme delta-aminolevulinic acid dehydratase (ALAD), the concentrations of deltaaminolevulinic acid and coproporphyrin in urine (UALA and UCP), and the blood hemoglobin and packed red blood cell volume (Hb and Hct) were measured by the methods described previously [Araki et al, 1983. BPb, MPb, PZn, MZn, PCu, MCu, the concentra tion of lead in plasma (PPb), the concentrations of zinc and copper in erythrocytes (EZn and ECu), and the amount of each metal spontaneously excreted in urine (UPb, UZn and UCu) were measured by atomic absorption spectrophotometry (Hitachi Polarized Zeeman Atomic Absorption Spectrophotometer 180-80), by the same meth ods as described in our previous reports Araki et al, 1984].…”

Daily rhythms in blood and milk lead toxicokinetics following intravenous administration of lead acetate to dairy cows in summer

“…Glomerular filtration has been reported to exert an important influence on lead rhythmicity in man. The results of profile analyses suggested that the circadian rhythm of Pb in urine was affected by its plasma and erythrocyte rhythms (Araki et al 1983).…”