Free cortisol

Initial screening tests to confirm the presence of hypercorti-solism and differentiate Cushing s syndrome from conditions with similar presentations include 24-hour urinary free cortisol determination and overnight low-dose dexam-ethasone suppression test (DST) (Table 42-9). 

Hour urinary Collect urine over 24 Urinary free cortisol greater Easy to perform but should not be used... 

Kirschbaum C., Wust S., Strasburger C. J. (1992). Normal cigarette smokingincreases free cortisol in habitual smokers. Life Sci. 50, 435-42. 

The presence of hypercortisolism can be established with a midnight plasma cortisol, late-night (11 PM) salivary cortisol, 24-hour urine free cortisol, and/or low-dose dexamethasone suppression test. 

Cyproheptadine can decrease ACTH secretion monitoring should include morning plasma cortisol and 24-hour urinary free cortisol concen-... 

Close monitoring of 24-hour urinary free cortisol levels and serum cortisol levels are essential to identify adrenal insufficiency in patients with Cushing s syndrome. Steroid secretion should be monitored with all drug therapy and corticosteroid replacement given if needed. 

Adrenal Tumours The assay-method is entirely based on the Schwartz-Mann Kit. According to this method, cortisol is first extracted from the plasma using CH2C12 (methylene chloride). In the actual radioimmunoassay the cortisol present in the extract competes with Cortisol-H3 i.e., the radioactive tracer) for the common binding sites on transcortin, which is incidently not an antibody but a cortisol-binding protein. Now, the free cortisol is quantitatively removed by adsorption on dextran-coated charcoal from the one bound to the transcortin. Finally, the bound radioactivity (due to Cortisol-H3) is measured which is then employed to calculate exactly the amount of cortisol present in the sample by the help of a Standard Curve (or Calibration Curve). 

Quickly add 0.5 ml of cold dextran-coated charcoal suspension to tubes 3 through 18 and to all patient sample tubes so as to get rid of free cortisol. Do not add to tubes 1 and 2,... 

Oral contraceptives have their most significant effect on endocrine parameters. Blood cortisol, thyroxine, protein-bound iodine, T3 uptake, and urinary free cortisol are elevated. Urinary 17,21-dihydroxy steroids, 17-ketosteroids, and estrogens are decreased. There is no effect on urinary catecholamines or VMA (Table 10) (LIO). The effect of thyroid functions tests is due to the administered hormone stimulating an increase in the production of thyroid-binding globulin which in turn binds 1-thyroxine. The lowering of free thyroxine stimulates the anterior pituitary to produce thyrotropin, which in turn stimulates the thyroid to produce more thyroxine. Since the additional thyroxine is bound to the extra protein, there is an equilibrium and the patient remains clinically euthyroid, but the protein-bound iodine and the thyroxine are elevated. 

Kanter et al. reported an increase concentration of the corticosteroid binding globulin (CBG) (Kanter et al. 2001). Most cortisol is bound to CBG, and is biologically inactive. A greater concentration of CBG is consistent with low levels of measurable free cortisol, and provides a putative explanation for how cortisol levels could be measurably low even though other aspects of HPA axis functioning do not seem hypoactive. However, the extent to which CBG levels are a contributing cause of low cortisol requires further examination. 

Wiist, S., Federenko, L, Hellhammer, D.H., and Kirschbaum, C. (2000) Genetic factors, perceived chronic stress, and the free cortisol response to awakening. Psychoneuroendocrinology 25 707-720. 

Many centers have reported specific abnormalities on measures of hypo-thalamic-pituitary-adrenal axis activity in patients with psychotic depression. Patients with psychotic major depression (PMD) are among those with the highest rates of nonsuppression on the dexamethasone suppression test, and many of them have markedly elevated posttest levels (Carroll et al. 1976c, 1980 Coryell et al. 1982). Significant differences have been observed in 24-hour measures of urinary free cortisol between patients with psychotic and those with nonpsychotic major depression (NPMD) (R. F. Anton 1987). 

Ansseau M, Olie JP, Von Frencheil R, et al Controlled comparison of the efficacy and safety of 4 doses of suriclone, diazepam and placebo in generahsed anxiety disorder. Psychopharmacology 104 439-443, 1991 Anton RF Urinary free cortisol in psychotic depression. Biol Psychiatry 2 24-34, 1987... 

Carroll BJ, Curtis GC, Mendels J Cerebrospinal fluid and plasma free cortisol concentration in depression. Psychol Med 6 235-244, 1976a... 

In patients in whom the diagnosis of Cushing s syndrome has been established clinically and confirmed by a finding of elevated free cortisol in the urine, suppression with large doses of dexamethasone will help to distinguish patients with Cushing s disease from those with steroid-... 

Table 5.3.2 The gas chromatography (GC)-MS urinary free cortisol (UFFj and metabolite panel internal standards, monitored ions, and normal excretions...

The method measures cortisone (urinary free cortisone, UFE), cortisol (urinary free cortisol, UFF), 6/1-hydroxycortisol, and 18-OHF using deuterated internal standards [62]. Commercial tetradeuterocortisol was used as an internal standard for cortisol, and the remaining dideutero homologs prepared in the laboratory by deuteration of A1 analogues. UFF and UFE are considered better indicators of hormone availability and hypersecretion than the F and E (free plus conjugated) quantified in the comprehensive profile. Typically the values of total F and E are about three times that of... 

Turpeinen U, Stenman U-H (2003) Determination of urinary free cortisol by liquid chromatography-tandem mass spectrometry. Scand J Clin Lab Invest 63 143-150... 

Sample extraction and deproteinization is usually accomplished with nonpolar organic solvents at a specified pH. Organic solvents such as chloroform for the determination of cortisol in milk (529) dichloromethane/hexane (4 1) for the determination of free cortisol and its 21-acetate in milk (530) ethyl acetate for the determination of prednisolone, fluoroprednisolone, triamcinolone, and betamethasone in animal tissues (531) methylprednisolone in milk (532) fluoro-prednisolone in milk (533) and dexamethasone in milk (534) ethyl acetate in... 

The long-term effects of budesonide on adrenal function have been assessed in 63 asthmatic children using budesonide 400 micrograms/day, nedocromil 16 mg/day, or placebo over 3 years (74). There were no differences in serum cortisol concentrations after ACTH stimulation between the three treatment groups, regardless of the time after ACTH administration or months of follow-up. Cumulative inhaled glucocorticoid exposure did not affect the serum cortisol response to ACTH or urinary free cortisol excretion at 3 years. 

Fink RS, Pierre LN, Daley-Yates PT, Richards DH, Gibson A, Honour JW. Hypothalamic-pituitary-adrenal axis function after inhaled corticosteroids unreliability of urinary free cortisol estimation. J Clin Endocrinol Metab 2002 87(10) 4541-6. 

On Days 1 and 10 CYP 1A2 activity was monitored using the plasma concentrations of caffeine and paraxanthine and CYP 3A4 activity was monitored using the urinary excretion of free cortisol and 6-(3>-hydroxy-cortisol. 

Concentrations of Drug XYZ, 6-fS-hydroxy-cortisol and free cortisol in urine collected over the profiling period were measured. Volumes of urine collected over each profiling period were recorded. 

Urinary b-p-hydroxy-cortisol and free cortisol The following pharmacokinetic variables were derived from urine concentration data for 6-P-hydroxy-cortisol and free cortisol on Days 1 and 10 using SAS for Windows protocols amount excreted during each collection interval for 6- 3-hydroxy-cortisol and free... 

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