Free cortisol in serum assayed by temperature-controlled ultrafiltration before fluorescence polarization immunoassay

Lentjes, Eef G.W.M.; Romijn, Fred P.H.T.M.; Maassen, Robert J.; Graaf, L. De; Gautier, P.; Moolenaar, A. J.

doi:10.1093/clinchem/39.12.2518

Cited by 35 publications

(6 citation statements)

References 9 publications

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“…AJP-Endocrinol Metab • VOL 287 • OCTOBER 2004 • www.ajpendo.org of 3.5 liters) and of cortisol of 3.6 Ϯ 0.2 mol⅐l Ϫ1 ⅐day Ϫ1 (ϳ12.8 mg⅐person Ϫ1 ⅐day Ϫ1 for a distribution volume of 10 liters). The foregoing estimates are consistent with values, where available, determined directly by isotope infusion in vivo or estimated by equilibrium dialysis at 37°C, pH 7.4, in vitro (6,10,12,23,26,27,(31)(32)(33).…”

Section: E657 Endogenous Acth Drive Of Cortisol Secretionsupporting

confidence: 84%

Endogenous ACTH concentration-dependent drive of pulsatile cortisol secretion in the human

Keenan¹,

Roelfsema²,

Veldhuis³

2004

American Journal of Physiology-Endocrinology and Metabolism

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According to current regulatory concepts, pulsatile ACTH concentrations (CON) stimulate time-lagged cortisol secretion rates (SEC) via an implicit CON-SEC dose-response relationship. The present analyses reconstruct nonlinear properties of this in vivo agonist-response interface noninvasively in order to investigate pulse-by-pulse coupling consistency and to obviate the need to infuse isotopes or exogenous effectors, which may disrupt pathway interactions. This approach required an ensemble strategy of 1) measuring ACTH and cortisol CON in plasma sampled every 10 min for 24 h in 32 healthy adults, and 2) estimating simultaneously a) variable-waveform ACTH and cortisol SEC bursts superimposed upon fixed basal SEC; b) biexponential kinetics of ACTH and cortisol disappearance; c) nonequilibrium exchange of cortisol among free and cortisol-binding globulin (CBG)- and albumin-bound moieties; d) two SEC-burst shapes demarcated by a statistically defined day/night boundary; e) feedforward efficacy, potency, and sensitivity; and f) stochastic variability in feedforward measures over time. Thereby, we estimate 1) ACTH SEC (microg.l(-1).day(-1)) of 0.27 +/- 0.04 basal and 0.87 +/- 0.07 pulsatile (means +/- SE); 2) cortisol SEC (micromol.l(-1).day(-1)) of 0.10 +/- 0.01 basal and 3.5 +/- 0.20 pulsatile; 3) free cortisol half-lives (min) of 1.8 +/- 0.20 (diffusion/advection) and 4.1 +/- 0.30 (elimination) and a half-life of total cortisol of 49 +/- 2.4 and of ACTH of 20 +/- 1.3; 4) ACTH potency (EC(50), ng/l) of 26 +/- 2.4, efficacy (nmol.l(-1).min(-1)) 10 +/- 1.8, and sensitivity (slope units) 0.65 +/- 0.09; 5) night/day augmentation of ACTH and cortisol SEC-burst mass by 2.1- and 1.7-fold (median); 6) abbreviation of the modal time to maximal ACTH and cortisol SEC rates by 4.4- and 4.3-fold, respectively, after a change point clock time of 0205 (median); 7) in vivo percentage distribution of cortisol as 6% free, 14% albumin bound, and 80% CBG bound with an absolute free cortisol CON (nmol/l) 11.5 +/- 0.54; and 8) significant (mean CV) stochastic variability in feedforward efficacy (140%), potency (38%), and sensitivity (56%) within the succession of paired ACTH/cortisol pulses of any given subject. In conclusion, the present composite formulation illustrates a platform for dissecting mechanisms of in vivo regulation of effector-response properties noninvasively in the corticotropic axis of the uninfused individual.

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Section: E657 Endogenous Acth Drive Of Cortisol Secretionsupporting

confidence: 84%

Endogenous ACTH concentration-dependent drive of pulsatile cortisol secretion in the human

Keenan¹,

Roelfsema²,

Veldhuis³

2004

American Journal of Physiology-Endocrinology and Metabolism

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“…The concentration of free cortisol was determined in the plasma samples of LO and UP LAI quartiles collected at 0 and 30 min after the ACTH challenge. The free fraction of cortisol was obtained via a temperaturecontrolled UF of plasma (Lentjes et al, 1993) using the Microcon YM-30 centrifugal filter device (cut-off 30,000, Millipore #42409, Millipore S.p.A., Vimodrone, Italy). The unbound cortisol in the ultrafiltrate was measured using the solid-phase RIA kit described above.…”

Section: Total and Free Cortisol Assaymentioning

confidence: 99%

Relation of inflammation and liver function with the plasma cortisol response to adrenocorticotropin in early lactating dairy cows

Trevisi

Bertoni

Lombardelli

et al. 2013

Journal of Dairy Science

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In this study we examined the relationship between cortisol and inflammatory status in early lactating dairy cows after a stimulation test of the adrenal cortex. Twenty-four cows were grouped into quartiles (6 cows per each quartile) in accordance with the liver activity index (based on plasma concentration of negative acute phase proteins in early lactation); the quartiles were lower (LO; cows with the lowest liver functionality), intermediate lower, intermediate upper, and upper (UP; cows with the highest liver functionality). Each cow was injected i.v. with 20 µg of a synthetic analog of ACTH at 35 d in milk (DIM). Blood samples were taken to assess inflammatory status, and at 0, 30, and 60 min after ACTH challenge to measure total cortisol. The free cortisol fraction was analyzed in the LO and UP quartiles and the bound cortisol fraction was estimated as the difference between total and free cortisol. The LO, in comparison with the other quartiles, suffered a more severe inflammatory status, with the highest values of haptoglobin, reactive oxygen metabolites, and total nitric oxide metabolites and the lowest concentration of direct or indirect markers of negative acute phase proteins. The cows in the LO quartile had the highest values of plasma nonesterified fatty acids and β-hydroxybutyrate at 7 DIM, suggesting a more severe body lipid mobilization. The LO quartile cows showed the highest frequency of health problems and the lowest milk yield in the first 35 DIM. Thirty minutes after the ACTH treatment, the concentration of total cortisol was lower in LO in comparison to other groups. Similarly, the bound cortisol fraction was lower in LO versus UP. The adrenal response appeared inversely related with health status after calving (e.g., lower in LO cows, experiencing the most severe inflammatory status). The lower increase in cortisol after the ACTH challenge in cows with greater inflammation (LO quartile) seems a consequence of the lower availability of cortisol-binding globulin synthetized by the liver, but other mechanisms can be involved (e.g., rate of cortisol production, secretion, and metabolic clearance). Our data provide evidence that inflammation and metabolic changes reduce the concentration of circulating plasma cortisol during an acute stress. Hence, the acute phase response in dairy cows should be taken into account to interpret the results obtained from stimulation tests of the adrenal cortex.

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“…Plasma concentrations of total cortisol were determined by fluorescence polarization immunoassay on the TDx (Abbott, Amstelveen, The Netherlands). Free cortisol was measured in the filtrate using the Amicon MPS-1 ultrafiltration device (Amicon Corp., Danvers, MA, USA) (10). The cortisol-binding globulin was determined by radioimmunoassay (Medgenix, Amersfoort, The Netherlands).…”

Section: Total and Free Cortisol And Cortisol-binding Globulinmentioning

confidence: 99%

Glucocorticoid receptors in cord blood lymphocytes of healthy neonates and of preterms suffering from respiratory distress syndrome

et al. 1997

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We measured the number of glucocorticoid receptors (GR) in cord blood lymphocytes and the binding affinity (Kd) in 15 term and in 20 preterm babies. Thirteen preterms of the latter group received prenatal steroid treatment. Seven preterms developed neonatal respiratory distress syndrome (NRDS). The number of GR and the Kd were similar in the term and preterm (with and without NRDS) babies. The maximum (3H)-thymidine incorporation into DNA of cord blood lymphocytes from all preterms, with or without NRDS was suppressed when compared to that from term babies or adults. This could partly be explained by the antenatal steroid treatment. Sensitivity (ID50) of the lymphocytes for the inhibitory effect of dexamethasone was the same in all groups. In this study on the number and function of GR in lymphocytes, we were unable to find a relation between the functionality of the GR and the development of NRDS.

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Free cortisol in serum assayed by temperature-controlled ultrafiltration before fluorescence polarization immunoassay

Cited by 35 publications

References 9 publications

Endogenous ACTH concentration-dependent drive of pulsatile cortisol secretion in the human

Endogenous ACTH concentration-dependent drive of pulsatile cortisol secretion in the human

Relation of inflammation and liver function with the plasma cortisol response to adrenocorticotropin in early lactating dairy cows

Glucocorticoid receptors in cord blood lymphocytes of healthy neonates and of preterms suffering from respiratory distress syndrome

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