Circadian Rhythm of Plasma Iron, Total Iron Binding Capacity and Serum Ferritin in Arteriosclerotic Aged Patients

Abstract

In 30 synchronized arteriosclerotic, but otherwise apparently normal, aged patients, a circadian rhythm can be demonstrated for plasma iron and total iron binding capacity, but not for serum ferritin. The features of the two rhythms are similar to those observed in adult subjects. In women an acrophase-shift of the two rhythms in comparison to men has been observed.

Diurnal cycle influences peripheral and brain iron levels in mice

“…This investigation was designed to examine the influence of diurnal cycle on iron distribution in the periphery and the brain in the iron-sufficient and ID states. Daily iron levels in the blood are not static and are known to fluctuate with the diurnal cycle, which is likely important for diurnal changes in oxygen transport, cell growth, and electron transfer (10,29). Our study extends these previous findings by examining diurnal fluctuations in liver, spleen, and regional brain iron in an ironsufficient and an ID RI strain of mouse.…”

“…The low point in serum iron occurs during the typically inactive evening hours, while the high point in serum iron occurs at midday (55,61). Total iron binding capacity (TIBC) has also been shown to vary with the light cycle (10). It has been hypothesized that the variations in serum iron and TIBC occur as a result of fluctuating iron release from reticuloendothelial cells.…”

Relationship between brain R2 and liver and serum Iron concentrations in elderly men

“…On the day of the MRI examination, the participants provided a fasting blood sample for measurement of serum iron and ferritin concentrations and calculation of the transferrin saturation, using previously published methods (21). To reduce natural fluctuations in serum, liver, or brain iron concentrations related to circadian cycles (22, 23), all participants provided their blood sample and received their MRI examination within a 4‐h period between 4 and 8 pm. These measurements contemporaneous with the MRI scan will be called time point 2 measurements.…”

Relationship of morningness-eveningness questionnaire score to ferritin, gamma glutamyl-transpeptidase and alanine amino-transferase concentrations in a large cohort

“…[32][33][34][35][36][37] However the studies are inconclusive for ferritin circadian variations, as literature supports ferritin levels have not been found to follow a circadian rhythm. 21,[33][34][35][38][39][40] In these studies, the relationship between iron biomarkers and subjective preferred timing of activity was never investigated. Our study found however a contradictory result for ferritin levels, as the significant differences according to chronotype suggests the hypothesis of a circadian variation for this parameter.…”

“…20,21,[33][34][35] However, diurnal variations in serum ferritin concentration were not demonstrated in most of the studies performed in humans. [38][39][40]21,34,35 Not only do circulating levels of various endocrine factors oscillate over the 24h period, but so too does responsiveness of target tissues, including the liver, to these signals or stimuli. 3,5,56 The circadian clock system in the liver plays important roles in regulating metabolism and energy homeostasis.…”