Diurnal variations of protein and electrolyte concentrations and of acid-base status in plasma and red cells of normal man

Böning, Dieter; Schweigart, U.; Kunze, Martin

doi:10.1007/bf00423219

Cited by 17 publications

(6 citation statements)

References 22 publications

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“…A further question concerns what adaptive advantage might be conferred upon RBC function by being able to anticipate the circadian organisation of organismal physiology. We speculate that cell autonomous circadian regulation of ion transport may help to counteract the increased osmotic burden to which blood cells are subject at night, when serum protein levels fall in vivo 39 . RBCs cannot accommodate this decrease in water potential by changes in the expression of transporters in the plasma membrane (as can other cells of the haemopoetic lineage), and yet cytosolic osmolality must be defended in order to prevent protein aggregation due to molecular crowding 40 .…”

Section: Discussionmentioning

confidence: 99%

Rhythmic potassium transport regulates the circadian clock in human red blood cells

et al. 2017

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Circadian rhythms organize many aspects of cell biology and physiology to a daily temporal program that depends on clock gene expression cycles in most mammalian cell types. However, circadian rhythms are also observed in isolated mammalian red blood cells (RBCs), which lack nuclei, suggesting the existence of post-translational cellular clock mechanisms in these cells. Here we show using electrophysiological and pharmacological approaches that human RBCs display circadian regulation of membrane conductance and cytoplasmic conductivity that depends on the cycling of cytoplasmic K+ levels. Using pharmacological intervention and ion replacement, we show that inhibition of K+ transport abolishes RBC electrophysiological rhythms. Our results suggest that in the absence of conventional transcription cycles, RBCs maintain a circadian rhythm in membrane electrophysiology through dynamic regulation of K+ transport.

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Section: Discussionmentioning

confidence: 99%

Rhythmic potassium transport regulates the circadian clock in human red blood cells

et al. 2017

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“…Oxygen content is calculated assuming a diurnal [Hb] variation as at sea level (Böning et al. ). Regression equation: [Epo] = −3.6 C a O 2 + 91 ( r = 0.35, P < 0.02).…”

Section: Discussionmentioning

confidence: 99%

Diurnal changes of arterial oxygen saturation and erythropoietin concentration in male and female highlanders

et al. 2016

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In Caucasians and Native Americans living at altitude, hemoglobin mass is increased in spite of erythropoietin concentrations ([Epo]) not markedly differing from sea level values. We hypothesized that a nocturnal decrease of arterial oxygen saturation (SaO2) causes a temporary rise of [Epo] not detected by morning measurements. SaO2 (continuous, finger oximeter) and [Epo] (ELISA, every 4 h) were determined in young highlanders (altitude 2600 m) during 24 h of usual daily activity. In Series I (six male, nine female students), SaO2 fell during the night with the nadir occurring between 01:00 and 03:00; daily means (range 92.4–95.2%) were higher in females (+1.7%, P < 0.01). [Epo] showed opposite changes with zenith occurring at 04:00 without a sex difference. Mean daily values (22.9 ± 10.7SD U/L) were higher than values obtained at 08:00 (17.2 ± 9.5 U/L, P < 0.05). In Series II (seven females), only SaO2 was measured. During follicular and luteal phases, SaO2 variation was similar to Series I, but the rhythm was disturbed during menstruation. While daily [Epo] variations at sea level are not homogeneous, there is a diurnal variation at altitude following changes in SaO2. Larger hypoventilation‐dependent decreases of alveolar PO2 decreases during the night probably cause a stronger reduction of SaO2 in highlanders compared to lowlanders. This variation might be enlarged by a diurnal fluctuation of Hb concentration. In spite of a lower [Hb], the higher SaO2 in women compared to men led to a similar arterial oxygen content, likely explaining the absence of differences in [Epo] between sexes.

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“…Both limitations are responsible for a decrease of V Ç O 2 max of the whole body and also of single muscle groups [23]. On the other hand, increasing hematocrit values induced by blood doping are known to improve the maximum oxygen uptake (e. g. [4]). The exact hematocrit value, however, beyond which the endurance performance would decrease again, has not been examined in healthy subjects.…”

Section: Discussionmentioning

confidence: 99%

How Valid is the Determination of Hematocrit Values to Detect Blood Manipulations?

Schmidt¹,

Biermann²,

Winchenbach³

et al. 2000

Int J Sports Med

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All experiments demonstrate that the Hct is not a constant value but can be considerably changed by physiological measures. Clinical studies show that brain oxygen supply decreases with increasing Hct-values, which are also associated with a higher risk of stroke accidents. We therefore recommend to use a Hct-limit solely under strongly controlled standardized conditions to protect professional cyclists from hazardous manoeuvre until more appropriate methods to detect EPO-doping are developed.

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Diurnal variations of protein and electrolyte concentrations and of acid-base status in plasma and red cells of normal man

Cited by 17 publications

References 22 publications

Rhythmic potassium transport regulates the circadian clock in human red blood cells

Rhythmic potassium transport regulates the circadian clock in human red blood cells

Diurnal changes of arterial oxygen saturation and erythropoietin concentration in male and female highlanders

How Valid is the Determination of Hematocrit Values to Detect Blood Manipulations?

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