Effect of sodium restriction on urinary excretion of cortisol and its metabolites in humans

Salt-sensitive men show reduced heart rate variability, lower norepinephrine and enhanced cortisol during mental stress

“…Young normotensive ss subjects do not reduce their peripheral cortisol levels nor increase urinary cortisol metabolite elimination under a high-salt diet as sr subjects do, 32 in line with the prior finding that cortisol excretion decreases under low-salt conditions in healthy subjects. 33 In accordance, subjects with the highest free cortisol excretion show the least sensitivity of BP to dietary sodium loading. 34 Thus, research presents both evidence for an altered ANS and HPA axis function in ss humans and animals.…”

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

“…Lewicka et al [ Table 1 of Ref. (6 )] listed in detail the amounts of urinary free corticosteroids and urine excreted per day; although not mentioned by the authors, the amounts of urinary free cortisone can be seen to have a positive relationship with the 24-h urine volumes (r ϭ 0.82; n ϭ 24; P Ͻ0.001). No such correlation existed between the 24-h urine volume and urinary excretion of free cortisol, tetrahydrocortisol, tetrahydrocortisone, or 18-hydroxycorticosterone.…”

“…Increased cortisone excretion should be considered in view of the facts that (a) urinary free cortisone excretion is 2-4 times higher than UFC (6,10,11,13 ), (b) cortisone significantly cross-reacts with the binding protein (3,4 ) or cortisol antibody (5 ) of the "cortisol" assays (Table 1), and (c) Hatfield and Shuster (2 ) reported in 1957 that "The excretion of free cortisone was greater at higher rates of urine but the results were too few for statistical analysis". Lewicka et al [ Table 1 of Ref.…”

Proper assessment of free corticosteroid excretion in human urine depends not only on the use of a reproducible analytical method but also on the attention that urine volume may be an important pre‐analytical parameter: a comment on the work of Al Sharef and co‐workers

“…The first of these limitations is that urinary free cortisol (UFF) and, especially, urinary free cortisone (UFE) may depend on urine volume. Corresponding results has been published in human individuals for UFF (Birmingham et al, 1998;Fenske, 2006b;Friedman and Papanicolaou, 1998;Gutenbrunner and Schreiber, 1987;Lundberg and Forsman, 1980;Mericq and Cutler, 1998) and for UFE (Fenske, 2006a,b;Lewicka et al, 1998). Thus, each investigator should check his or her data with respect to a possible relation between steroid excretion and urine volume.…”