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Use of sodium salicylate as a blocking agent for cortisol-binding-globulin in a radioimmunoassay for cortisol on unextracted plasma.

This report describes investigations into the use of sodium salicylate as a cortisol-binding-globulin blocking agent and the subsequent development of a radioimmunoassay for cortisol on unextracted plasma. Cortisol antiserum was raised against a cortisol 3-O-(carboxy-methyl) oxime-bovine serum albumin conjugate. A 125I-labelled cortisol-tyrosine methyl ester conjugate was also prepared for use in the assay. The radioimmunoassay developed involved no pre-treatment of extraction of the samples before analysis and was extremely simple to perform. Comparison with another radioimmunoassay for cortisol and with the Mattingly fluorimetric assay gave good correlation.

Anilino Naphthalenesulfonates↗

Corticotropin-releasing hormone directly stimulates cortisol and the cortisol biosynthetic pathway in human fetal adrenal cells.

Near term the human fetal adrenals (HFAs) initiate production of cortisol, which promotes organ maturation and acts to increase placental CRH biosynthesis. The objective of the present study was to determine whether CRH directly stimulates both cortisol production and expression of the steroidogenic enzymes in HFA-definitive zone cells. CRH stimulated the production of cortisol in a time- and dose-dependent manner, with an effective concentration of as low as 0.01 nm. In real-time RT-PCR experiments, CRH treatment increased the mRNA levels of steroidogenic acute regulatory protein and each of the enzymes needed to produce cortisol. CRH induced 3beta-hydroxysteroid dehydrogenase type II (HSD3B2) by 34-fold, 21-hydroxylase (CYP21) by 55-fold, and 11beta-hydroxylase by 41-fold. Induction of steroidogenic acute regulatory protein, cholesterol side chain cleavage (CYP11A), and 17alpha-hydroxylase (CYP17) mRNA by CRH was 6-, 4-, and 6-fold, respectively. We also demonstrated that submaximal concentrations of CRH (30 pm) and ACTH (30 pm) that are seen in fetal circulation were additive on cortisol biosynthesis and 3beta-hydroxysteroid dehydrogenase type II mRNA induction. We suggest that CRH may play an important role in the late gestational rise in cortisol secretion from the HFAs, which may serve to augment placental CRH production and therefore participate in the endocrine cascade that is involved in fetal organ maturation and potentially in the timing of human parturition.

3-Hydroxysteroid Dehydrogenases↗

The daily cortisol production reinvestigated in healthy men. The serum and urinary cortisol production rates are not significantly different.

We have measured the urinary cortisol production rate (uCPR) simultaneously with the serum cortisol production rate (sCPR) in four healthy men within a period of 3 days. uCPR, determined by isotope dilution of 11-oxoetiocholanolone was compared with sCPR, which was measured in three different ways (a, b, c). Blood was sampled at 10-min intervals for 24 h, and deconvolution analysis was applied to the cortisol concentrations. The daily serum cortisol production per liter, multiplied by the distribution volume yielded sCPR. The measurement methods are characterized as follows: a) the secretion and elimination terms were free; b) like method a, but with the input of the rate constants alpha and beta into the elimination function; c) the average 24-h cortisol concentration was multiplied by the metabolic clearance rate. uCPR was 25.4 +/- 4.7 [range: 21.3-31.4] micromol/(m2 x day), sCPR (method a) was 28.8 +/- 4.5 [range: 23.5-34.3] micromol/(m2 x day), sCPR (method b) was 27.9 +/- 8.1 [range: 18.5-37.7] micromol/(m2 x day), and sCPR (method c) was 29.3 +/- 4.8 [range: 22.7-33.2] micromol/(m2 x day). uCPR did not significantly differ from each of the 3 sCPR values (P > 0.30; > 0.46; and > 0.06, respectively). The patterns of the cortisol secretory rates in the present and previous studies do not necessarily represent the physiological process of the secretory bursts. We conclude that the estimated CPR, being 25-30 micromol/(m2 x day) [9-11 mg/(m2 x day)], can serve as a guideline for glucocorticoid replacement dose and that the urinary route to measure CPR is preferred because of its relative ease.

Humans↗

Measurement of urinary free cortisol using liquid chromatography-tandem mass spectrometry: comparison with the urine adapted ACS:180 serum cortisol chemiluminescent immunoassay and development of a new reference range.

BACKGROUND: The measurement of urinary free cortisol (UFC) is commonly used in the investigation of possible Cushing's syndrome. With the recent availability of liquid chromatography-tandem mass spectrometry (LC-MS/MS) in hospital laboratories, we wanted to develop a specific UFC LC-MS/MS method and compare it with our current immunoassay method and develop a new LC-MS/MS reference range if required. METHODS: A UFC LC-MS/MS method using deuterated cortisol as an internal standard was optimized using solid-phase extraction as a clean-up procedure. The multiple reaction-monitoring transitions used for the detection of cortisol and deuterated cortisol were 363.1 > 121 and 365.1 > 121.8, respectively. The method was investigated regarding precision, linearity, sensitivity, recovery and interference. UFC was measured by the in-house urine adapted ACS:180 serum cortisol immunoassay and the developed LC-MS/MS method in 110 urine samples from patients being investigated for possible Cushing's syndrome. RESULTS: The within-batch precisions (n = 25) of the LC-MS/MS method were 7.6%, 4.5% and 3.3% at 25.0 nmol/L, 49.6 nmol/L and 344.6 nmol/L, respectively; the between-batch precisions (n = 10) were 9.4%, 9.4% and 8.4%, respectively, at these concentrations. The method is sensitive down to 5 nmol/L and linear up to at least 1000 nmol/L. The method showed adequate cortisol recovery and no interference from the numerous drugs and steroids tested. The total run time for 20 samples, including sample preparation, was 120 min. A scatter plot of paired UFC measurements on the LC-MS/MS and the ACS:180 gave the equation: LC-MS/MS = 0.408 (ACS:180) + 2.65, r2 = 0.6664. The 24-h measured UFC results on 110 samples (25 men and 85 women) were positively skewed. After log transformation the data were less skewed, and following back transformation of the lower 97.5th centile, the upper limit of normal was 165 nmol/24 h. The 95th centile of the untransformed data was 146 nmol/24 h (n = 110, 25 men and 85 women). Separated by sex, the 95th centile was 152 nmol/24 h for men (n = 25) and 141 nmol/24 h for women (n = 85). CONCLUSIONS: We have developed a UFC LC-MS/MS method with a solid-phase extraction clean-up step. The method shows adequate performance and is suitable for routine laboratory use. The mixed sex (n = 110, men = 25, women = 85) reference range was up to 165 nmol/24 h or 146 nmol/24 h, depending on how the data are manipulated.

Chromatography, Liquid↗

Effect of transportation on cortisol concentrations and on the circadian rhythm of cortisol in gilts.

A study was conducted to determine whether the circadian rhythm of cortisol in gilts is disrupted or altered by transport. Sixteen ovariectomized gilts with indwelling jugular catheters were individually penned in an enclosed building (location 1). Blood samples were collected at 0700 and 1900 hours for 6 days. On day 7, gilts in groups of 4 were transported 5.6 km to environmentally controlled chambers (25 C) and were individually penned (location 2). On the day of transport, samples were collected at 0700 hours at location 1, immediately before and after transport in a trailer, after unloading at location 2, and at 1900 hours at location 2. For the first 6 days at location 2, blood samples were collected daily at 0700 and 1900 hours. For the 6 days at location 1, circadian rhythm was evidenced by higher cortisol concentrations in the AM hours than in the PM hours. During transport, serum cortisol concentrations increased (P less than 0.01). Highest concentrations developed at 0.5 hour after unloading; concentrations declined thereafter. During the first 6 days at location 2, circadian rhythm was evidenced by higher serum cortisol concentrations in the AM hours than in the PM hours. Therefore, the transportation of gilts 5.6 km to new pens was a transient stress causing a temporary increase in serum cortisol concentrations, but did not cause a disruption in the endogenous rhythm of cortisol.

Animals↗

[Comparative determination of transcortin, total cortisol and free cortisol in the plasma of mothers, newborn and non-pregnant women (author's transl)].

We determined plasma transcortin, total cortisol and free cortisol in mothers, new borns and nonpregnant women. The blood samples were drawn immediately upon delivery. The mothers had significantly higher levels of total cortisol as well as free cortisol and transcortin when compared to non-pregnant women. The new borns had higher levels of total cortisol and free cortisol but unchanged levels of transcortin in comparison to normal subjects. Significant differences were also found with respect to total protein and albumin in all groups.

Blood↗

[Log-normal distributed plasma cortisol levels of four daily measurements in normal subjects. A comparison of the fluorescence method after de Moor with a radioimmuno assay of plasma cortisol (author's transl)].

The present paper describes the plasma cortisol concentrations on four daily measurements in normal subjects assayed with the fluorescence method after de Moor and with a radioimmuno assay. A comparison of these two methods shows that the determinations of plasma cortisol with the fluorescence method always yielded higher values. Both methods are sensitive enough to detect the circadian rhythm of cortisol secretion. For the purpose of routine diagnostics it is sufficient to measure the maximal and minimal concentrations of plasma cortisol in blood samples taken at 8 a.m. and 8 p.m., respectively. The plasma cortisol measurements should only be attempted after allowing a few days of adaption to the hospital situation. Table 2 shows that the normal plasma cortisol levels are represented only by log-normal distributed values. These concentrations are lower than the linear distributed levels reported so far.

Adult↗

Effect of acceleration stress on salivary cortisol and plasma cortisol and testosterone levels in cadet pilots.

The effects of acceleration (Gz) on changes in the levels of cortisol in saliva and of cortisol and testosterone in serum have been studied in 48 cadet pilots exposed to a linear acceleration gradient (0.2 G/s) until a loss of coordination when the mean G value was found to be 5.94 +/- 0.57. Three patterns of salivary cortisol responses were discerned based on Gz-induced significant changes: increase (I; n = 20), decrease (D; n = 8), the magnitude of changes being dependent on the pre-Gz values. Fifteen min after the Gz load, the mean salivary cortisol was significantly higher from the pre-Gz value in all subjects combined. In 19 subjects, who consented to blood sampling, significant increases in serum cortisol were observed both 3 and 15 min post-Gz (by 37 and 57% respectively) while, a significant increase in serum testosterone concentration has been observed only 3 min post-Gz. Testosterone levels 3 min post-Gz were significantly correlated with the final Gz values (r = 0.54; p < 0.05). A significant correlation was also observed between all salivary and serum cortisol values combined (r = 0.696; p < 0.001). It has been concluded that acceleration stress, although of very short duration, proved very potent in eliciting glucocorticoid and androgen responses.

Acceleration↗

Dampening of the cortisol response to handling at 3 months in human infants and its relation to sleep, circadian cortisol activity, and behavioral distress.

The decrease in responsiveness of the hypothalamic-pituitary-adrenocortical (HPA) system is marked over the first months of life. Seventy-eight healthy infants (44 girls), 7 to 15 weeks old, were given a laboratory mock physical examination. Salivary cortisol samples were collected pre- and postexamination and at home. Behavioral state during the examination and home sleep/wake activity were measured. Subjects younger than 11 weeks showed an increase in pre- to postexamination cortisol, while older subjects did not. Further, there was no decrease in behavioral distress to the examination with age. Infants who showed an early- morning peak (EMP) in home cortisol levels were significantly older and were likely to be those who slept through the night. However, the presence of an EMP was not associated with a lack of cortisol response to the examination. The decrease in cortisol responsiveness witnessed around the age of 3 months is presumably due to other processes associated with age, and not with the expression of the day-night rhythm in basal cortisol.

Arousal↗

Adaptation of DELFIA cortisol kit for determination of salivary cortisol concentration.

Salivary cortisol concentration seems to be an excellent indicator of the biologically active plasma cortisol level because of the nearly absence of corticoid-binding proteins in saliva. With regard to the easy, noninvasive, and stress-free nature of saliva sampling, this parameter greatly facilitates studies of the HPA (hypothalamus-pituitary-adrenocortical) axis, especially in children. A commercially available TR-FIA (time-resolved fluoroimmunoassay), the DELFIA (dissociation-enhanced lanthanide fluoroimmunoassay) method, proposed for plasma and urine cortisol analyses, was adapted for salivary cortisol measurement by means of simple modifications of the assay protocol. The sensitivity was determined to be 0.53 nmol/L. The intra- and interassay coefficients of variation ranged from 5.5 to 8.2 % and from 6.0 to 10.4 %, respectively. The present findings suggest that the DELFIA procedure provides a reliable, sensitive, and convenient alternative procedure to the assay for salivary cortisol.

Adult↗

Seasonal changes in osmoregulation, cortisol, and cortisol receptor activity in the gills of parr/smolt of steelhead trout and steelhead-rainbow trout hybrids, Oncorhynchus mykiss.

Steelhead and hybrid trout (rainbow trout male, steelhead female) presmolts and smolts, Oncorhynchus mykiss, exposed to 30/1000 seawater (SW) for 24 hr manifested progressively lower plasma sodium values from December to May. The increase in plasma sodium after 24 hr in SW diminished significantly after March, with the hybrids (which were heavier in weight than the steelheads) reaching their peak osmoregulatory ability in the middle of April, and the steelheads in late May. In fresh water there was little difference in plasma osmotic concentration but steelhead plasma chloride fell significantly from March 30 levels to May 23 levels, whereas hybrid plasma chloride levels did not change during this time. In steelheads but not hybrids, plasma cortisol correlated negatively with plasma sodium of fish exposed 24 hr in SW. However, in both steelheads and hybrids, plasma sodium values 24 hr after SW exposure had an inverse correlation with cytosol cortisol from the gills. Again, in both steelheads and hybrids, plasma values of fish exposed 24 hr in SW correlated positively with cytosol receptor activity. In hybrids, the nuclear extract receptor activity, Nmax, increased significantly until late March and then dropped significantly thereafter. In steelheads, there were no significant differences but Nmax followed the same trends as occurred in hybrids. Thus seasonal changes in cortisol and cortisol receptors in steelhead occur during smoltification and preparation for marine life and suggest an important role for cortisol. In hybrids there appears to be a reduction in seasonality.

Animals↗

Relationship of 24-hour urinary free cortisol to 4-hour salivary morning and afternoon cortisol and cortisone as measured by a time-integrated oral diffusion sink.

The relationship between salivary corticosteroids integrated over 4-hour periods and urinary free cortisol collected over 24 hours was investigated in normal controls. Twenty-one normal volunteers wore "oral diffusion sink" sampling devices in their mouths for two 4-hour periods (08:00-12:00 hours and 13:00-17:00 hours) and on the same day collected a 24-hour urine specimen. Time-integrated salivary corticosteroid concentrations were determined from the sample devices and urinary free cortisol was measured. Salivary corticosteroids were not consistently higher in the morning than in the afternoon period and did not differ between men and women. Urinary free cortisol levels were higher in women. No salivary corticosteroids measure was significantly correlated with urinary free cortisol. We conclude that time-integrated salivary corticosteroids do not reflect urinary free cortisol levels in normal controls.

Adult↗

Relative competition of corticosterone, cortisol, cortisone, 11-dexycortisol and prednisolone with (1,2-3H)-cortisol in various protein-binding radioassay systems.

The relative influence of some endogenous corticosteroids and of synthetic prednisolone on competitive protein-binding radioassay was compared with that of cortisol, using as a source of transcortin pooled plasmas from various species and at different dilutions. Human (different clinical situations), cow, dog, sheep, hog, rabbit and chicken plasma were examined. The ability of corticosterone, cortisone, 11-deoxycortisol and prednisolone to displace [1,2-3-H] cortisol from corticosteroid-binding globulin (CBG) was measured: (1) by assessing the amounts (ng/tube) which produce a displacement equal to 10 ng/tube of cortisol, and (2) by calculating the integrated areas of displacement defined by the binding curves and by expressing them as a percentage of the cortisol curve area. While corticosterone, 11-deoxycortisol and prednisolone have a binding potency not very different from that of cortisol in almost the entire set of competitive protein-binding assays tested, the binding ability of cortisone was found to be particularly dependent upon the species of diluted plasma. Differences in the relative specificity of binding are apparent also within the human species, depending on the source of diluted plasma, whereas the concentration of endogenous steroids does not seem to significantly affect binding curves under the conditions examined. It is suggested that binding proteins in various conditions differ from those of healthy adults not only quantitatively but also qualitatively.

Addison Disease↗

Progesterone in the uterus. VII. Uptake of cortisol and incorporation of progesterone under simultaneous application of cortisol into rat uterus.

After injection of radioactively labelled cortisol, the distribution of the radioactivity in the subcellular fractions of the rat uterus (nuclei, mitochondria, microsomes and 105 000 X g supernatant) was studied. In all fractions, radioactivity was observed and maxima were found 10, 20 and 50 min. after injection of the labelled hormone. Radioactivity was measured in all subcellular fractions even 180 min. after application of labelled cortisol. Additionally, radiolabelled progesterone and unlabelled cortisol in the ratio 1:1 or 1:2 (moles:moles) were injected into the animals. Studying the uptake of labelled progesterone in the subcellular fractions of the uterine tissue, revealed that no competition of unlabelled cortisol could be observed 10, 20 and 50 min. after application of the hormone mixture, compared with the control experiments. The results of this study give evidence that the progesterone uptake into rat uterus is specific and cannot be influenced by unlabelled cortisol.

Animals↗

Determination of cortisol in human plasma by capillary gas chromatography-mass spectrometry using [2H5] cortisol as an internal standard.

A capillary gas chromatographic-mass spectrometric method for the determination of cortisol in human plasma using cortisol M + 5 as an internal standard is described. For calculation of plasma cortisol, peak areas were measured by selected-ion monitoring of the characteristic fragment ions of the dimethoxime-tri (trimethylsilyl) derivatives of cortisol and cortisol M + 5 (m/z 605 and 610, respectively). The inter- and intra-assay coefficients of variation for plasma sample were 3.07 and 1.77%, respectively. The method needed no complex corrections for contributions and provides a sensitive and reliable technique with good accuracy, precision and reproducibility.

Deuterium↗

Synthesis of a cortisol-biotin conjugate and evaluation as a tracer in an immunoassay for salivary cortisol measurement.

Cortisol 3-(o-carboxymethyl)oxime (C3-CMO) and a commercially available biotin-hydrazide derivative were used to synthesize a C3-CMO-biotin conjugate. C3-CMO was converted into a N-hydroxysuccinimide ester derivative which in a second reaction step was allowed to interact with the hydrazide derivative of biotin. This simple-to-perform synthesis yielded a conjugate suitable for use as a tracer in immunoassays for cortisol measurement. Employing biotin as the primary probe in a competitive solid phase immunoassay allows for variable end point determination by means of commercially available labeled avidin or streptavidin derivatives. Streptavidin-Europium was used in conjunction with the DELFIA-system for time-resolved fluorometric end point measurement (TR-FIA) throughout the study. In addition, colorimetric end point determination (ELISA) using streptavidin-alkaline phosphatase as a secondary probe was established and evaluated. Both forms of this non-isotopic assay showed excellent correlation with a commercially available radioimmunoassay adapted for salivary cortisol measurement. The lower detection limit was 0.43 nM for a 50 microliters salivary sample. The intra-assay coefficient of variation was 6.7, 4.7 and 4.0% at cortisol concentrations of 2.2, 5.5 and 13.2 nM, respectively (n = 37), and the corresponding inter-assay coefficients of variation were 9.0, 8.6 and 7.1% (n = 50). The competitive immunoassay requires 1.5 h incubation time and shows robust and reproducible performance. The C3-CMO-biotin conjugate allows for sensitive and flexible end point determination of salivary cortisol levels in immunoassays.

Biotin↗

Simultaneous determination of 6beta-hydroxycortisol and cortisol in human urine by liquid chromatography with ultraviolet absorbance detection for phenotyping the CYP3A activity determined by the cortisol 6beta-hydroxylation clearance.

This study describes a high-performance liquid chromatographic (HPLC) method for the simultaneous determination of 6beta-hydroxycortisol (6beta-OHF) and cortisol in human urine using either methylprednisolone or beclomethasone as internal standard. Separation was achieved on a reversed-phase phenyl column by a gradient elution of 0.05 M KH(2)PO(4)-0.01 M CH(3)COOH (pH 3.77) and 0.05 M KH(2)PO(4)-0.01 M CH(3)COOH with acetonitrile (4:6, v/v). 6beta-Hydroxycortisol and cortisol were monitored by UV absorption at 239 nm. The lower quantitation limits of the present HPLC method were 21.5 ng/ml for 6beta-OHF and 5.0 ng/ml for cortisol in urine. The within-day reproducibilities in the amounts of 6beta-OHF and cortisol determined were in good agreement with the actual amounts added, the relative error being less than 1.59%. The inter-assay precisions (R.S.D. values) were less than 7.91% for 6beta-OHF and cortisol. The method was compared with the GC/MS method by measuring 6beta-OHF in the same urine samples. A good correlation was found between the amounts determined by the two methods. The regression equations for the HPLC (y) and GC/MS (x) methods were: y=1.0701x+17.389 (r=0.9772) for methylprednisolone as internal standard and y=1.0827x+6.1364 (r=0.9794) for beclomethasone as internal standard.

Anti-Bacterial Agents↗

Baseline cortisol levels, cortisol response to corticotropin, and prognosis in late septic shock.

The prognostic value of basal and corticotropin-stimulated cortisol concentration in patients with sepsis remains a controversial issue. In a retrospective cohort study, 82 consecutive patients with septic shock underwent a short corticotropin test performed more than 24 h after the onset of vasopressor therapy. Forty-one (50%) patients died within 28 days after the onset of septic shock. The mean (SD) basal cortisol level was 22.7 (10.6) microg/dL. With threshold values of 7 and 9 microg/dL maximal increases in cortisol level, 28 (34%) and 31 (38%) patients were, respectively, classified as nonresponders to the short corticotropin test. On multivariate analysis, a cortisol level >20 microg/dL (P = 0.0002), a maximal response to corticotropin <9 microg/dL (P = 0.044), abnormal lactate values (P = 0.0098), and positive blood cultures (P = 0.004) were independent predictors of 28-day mortality. In conclusion, high basal cortisol and low increase on corticotropin stimulation are predictors of a poor outcome in late septic shock. The underlying mechanisms of these prognostic patterns remain to be elucidated.

Adrenocorticotropic Hormone↗