How Much “Urinary Free Cortisol” Is Really Cortisol during Water Diuresis in Healthy Individuals?

Comment on “Diurnal excretion of urinary cortisol, cortisone, and cortisol metabolites in chronic fatigue syndrome”

“…If one takes his so-called bcorticosteroidsQ as UFC and UFCn, it clear that UFCn (the main urinary free glucocorticosteroid) excretion depends on urine volume. This is corroborated by previous literature showing a significant positive relation between UFCn excretion and urine volume [4,11,12]. Thus, interpretation of the UFCn values presented by Jerjes et al [1] is difficult or even impossible if fluid intake is not strictly controlled [12].…”

“…This is corroborated by previous literature showing a significant positive relation between UFCn excretion and urine volume [4,11,12]. Thus, interpretation of the UFCn values presented by Jerjes et al [1] is difficult or even impossible if fluid intake is not strictly controlled [12]. Interpretation of UFCn data (and thus also of UFC) is further complicated by the fact that UFC and UFCn excretion changes with daytime (see above).…”

Avtomatizirovannyy elektrokhemilyuminestsentnyy metod opredeleniya kortizola v slyune dlya diagnostiki endogennogo giperkortitsizma sredi patsientov s ozhireniem

“…Сбор мочи в течение 24 часов связан с возможностью потери или неправильного измерения общего объема. Кроме того, избыточное потребление жидкости и снижение функции почек влияют на уровень свободного кортизола в моче [3,4]. Малая проба с дексаметазоном требует забора крови и фармакологического вмешательства, к которому некоторые пациенты могут относиться с настороженностью.…”

High Cognitive Dietary Restraint Is Associated With Increased Cortisol Excretion in Postmenopausal Women: A Comment

“…They observed that cortisone, a major metabolite of UFF in the urine, demonstrated a crossreactivity of 44%, and they concluded that this method overestimates urinary cortisol, giving results up to twice those obtained by a specific gas chromatography-mass spectrometry method. Thus, we may assume that Rideout and colleagues (1) measured the sum of free cortisol and urinary free cortisone (UFE) excretion [for discussion, see (3)], and that the observed changes were mainly due to changes of UFE excretion; this may especially be true if urine volume is increased [see also (4,5)]. Thus, their finding ''we were surprised to find a relatively strong relationship between mean total water intake and cortisol excretion'' [(1), p. 632] should be changed as follows: ''we were surprised to find a relatively strong relationship between mean total water intake and corticosteroid (UFF 1 UFE) excretion.''…”

“…Thus, their finding ''we were surprised to find a relatively strong relationship between mean total water intake and cortisol excretion'' [(1), p. 632] should be changed as follows: ''we were surprised to find a relatively strong relationship between mean total water intake and corticosteroid (UFF 1 UFE) excretion.'' Unfortunately, the results of Rideout and colleagues (1) will not be improved if results would be reworked and the volume of each 24-hour urine would be taken into calculation since urinary steroid excretion depends also on daytime: An increase of urine volume in the morning (zenith of adrenocortical secretion) will have a more pronounced effect on steroid excretion than an increase of urine volume in the evening [nadir of adrenocortical secretion (3,6)].…”