Residual Corticosteroid Production in Autoimmune Addison Disease.

CONTEXT: Contrary to current dogma, growing evidence suggests that some patients with autoimmune Addison disease (AAD) produce corticosteroids even years after diagnosis. OBJECTIVE: To determine frequencies and clinical features of residual corticosteroid production in patients with AAD. DESIGN: Two-staged, cross-sectional clinical study in 17 centers (Norway, Sweden, and Germany). Residual glucocorticoid (GC) production was defined as quantifiable serum cortisol and 11-deoxycortisol and residual mineralocorticoid (MC) production as quantifiable serum aldosterone and corticosterone after > 18 hours of medication fasting. Corticosteroids were analyzed by liquid chromatography-tandem mass spectrometry. Clinical variables included frequency of adrenal crises and quality of life. Peak cortisol response was evaluated by a standard 250 µg cosyntropin test. RESULTS: Fifty-eight (30.2%) of 192 patients had residual GC production, more common in men (n = 33; P < 0.002) and in shorter disease duration (median 6 [0-44] vs 13 [0-53] years; P < 0.001). Residual MC production was found in 26 (13.5%) patients and associated with shorter disease duration (median 5.5 [0.5-26.0] vs 13 [0-53] years; P < 0.004), lower fludrocortisone replacement dosage (median 0.075 [0.050-0.120] vs 0.100 [0.028-0.300] mg; P < 0.005), and higher plasma renin concentration (median 179 [22-915] vs 47.5 [0.6-658.0] mU/L; P < 0.001). There was no significant association between residual production and frequency of adrenal crises or quality of life. None had a normal cosyntropin response, but peak cortisol strongly correlated with unstimulated cortisol (r = 0.989; P < 0.001) and plasma adrenocorticotropic hormone (ACTH; r = -0.487; P < 0.001). CONCLUSION: In established AAD, one-third of the patients still produce GCs even decades after diagnosis. Residual production is more common in men and in patients with shorter disease duration but is not associated with adrenal crises or quality of life.

Seated saline infusion test in predicting subtype diagnosis of primary aldosteronism.

CONTEXT: Although saline infusion test is widely used as a confirmatory test for primary aldosteronism (PA), it is reportedly less sensitive in patients in whom aldosterone is responsive to the upright position by performing it in recumbent position. Based on a single-centre experience, seated saline infusion test (SSIT) has been reported to be highly sensitive and superior to recumbent testing in identifying both unilateral and bilateral forms of PA. However, due to limited participants number, the utility of SSIT needs to be validated in other series. OBJECTIVE: This study aimed to evaluate the accuracy of SSIT in determining the PA subtypes compared with adrenocorticotropic hormone stimulation test under dexamethasone suppression (Dex-AT). PATIENTS AND SETTING: Sixty-four patients with PA who underwent both SSIT and Dex-AT were included. Subtype diagnosis of PA was determined by adrenal venous sampling (AVS) (16 unilateral and 48 bilateral forms). MAIN OUTCOME MEASURE: Plasma aldosterone concentrations (PACs) were measured after SSIT and Dex-AT. RESULTS: The area under the receiver operating characteristic (ROC) curve for diagnosing unilateral PA was greater in SSIT than that in Dex-AT (0.907 vs. 0.755; P = .023). ROC curve analysis predicted optimal cut-off PACs of 13.1 ng/dL (sensitivity, 93.8%; specificity, 79.2%) for SSIT and 34.2 ng/dL (sensitivity, 75.0%; specificity, 68.8%) for Dex-AT. CONCLUSIONS: Seated saline infusion test has superior accuracy in subtype diagnosis of PA compared with Dex-AT. SSIT can be a sensitive test for determining patients who require AVS prior to surgery.

Adsorption effects of the doping relevant peptides Insulin Lispro, Synachten, TB-500 and GHRP 5.

The tendency of peptides to adsorb to surfaces can raise a concern in variety of analytical fields where the qualitative/quantitative measurement of low concentration analytes (ng/mL-pg/mL) is required. To demonstrate the importance of using the optimal glassware/plasticware, four doping relevant model peptides (GHRP 5, TB-500, Insulin Lispro, Synachten) were chosen and their recovery from various surfaces were evaluated. Our experiments showed that choosing expensive consumables with low-bind characteristics is not beneficial in all cases. A careful selection of the consumables based on the evaluation of the physico/chemical features of the peptide is recommended.

Adrenal Suppression With Chronic Topical Corticosteroid Use in Psoriasis Patients.

BACKGROUND: Topical corticosteroids (TCS) are typically used for extended periods of time for chronic skin conditions, including psoriasis. Chronic TCS use may result in side effects similar to those of systemic corticosteroids. Patients may have subclinical adrenal suppression and be unaware of their risk in the case of serious trauma.
OBJECTIVE: The objective of this study was to investigate the real world effects of chronic TCS use and its effects on adrenal suppression in a chronic disease such as psoriasis.
MATERIALS: This retrospective study utilized data from screening visits of a psoriasis clinical trial in which subjects had been on chronic TCS.
RESULTS: In this study, subjects with moderate to severe psoriasis affecting 16-20% of total body surface area (BSA) and using high-potency TCS at screening had a lower post-cosyntropin cortisol level (18.83 mcg/dL) compared to those with moderate psoriasis involving 10-15% of total BSA and using lower potency TCS at screening (23.22 mcg/dL; P=0.03). Both subject groups had lower post-cosyntropin cortisol levels compared to normal, healthy adults (P<0.001 for both).
CONCLUSION: This suggests that real world chronic use of high potency TCS over a larger BSA may result in silent adrenal suppression.

J Drugs Dermatol. 2016;15(8):945-948.

Hypothalamus-pituitary dysfunction is common in patients with stable cirrhosis and abnormal low dose synacthen test.

BACKGROUND: Adrenal insufficiency is often present in cirrhosis. We hypothesize that a prolonged adrenocorticotropic hormone (ACTH) stimulus can restore cellular capacity of adrenal glands to secrete cortisol. Aim of our study was to assess adrenal responsiveness to prolonged ACTH stimulation in cirrhotics. METHODS: Prospective observational study in 121 consecutively admitted cirrhotic patients undergoing a low dose short synacthen test and plasma ACTH measurement using a chemiluminescence immunoassay. Long synacthen test was performed if the low dose was abnormal. RESULTS: 46 patients had abnormal low dose short test (38%), and 29 underwent the long test: 41% showed normal response (Group 1), 55% showed delayed response (Group 2) and 1 had abnormal response (4%). Baseline ACTH levels did not significantly differ between the two groups. Median basal cortisol was higher in Group 1 (296 vs. 198 nmol/L; p=0.02). Using ROC curve basal cortisol <254 nmol/L was associated with a delayed long synacthen test response (AUC 0.78, p=0.001) with good accuracy (sensitivity 67%, specificity 81%). CONCLUSION: A delayed cortisol response after a prolonged ACTH stimulation is found in over fifty percent of cirrhotics with abnormal low dose short synacthen test, confirming that the mechanism of hypoadrenalism in these patients could be related both to adrenal cellular dysfunction and hypothalamus-pituitary adrenal axis impairment.

Steroid Profiling by LC-MS/MS in Nonsecreting and Subclinical Cortisol-Secreting Adrenocortical Adenomas.

CONTEXT: Long-term follow-up studies revealed that patients with subclinical hypercortisolism (SH) due to adrenocortical adenomas have an increased incidence of cardiovascular diseases and mortality. No studies have yet investigated the steroid profile and its implications in patients with SH. OBJECTIVE: The objective of the study was to analyze the steroid profile by liquid chromatography-tandem mass spectrometry in sera from patients with unilateral adrenocortical adenomas. DESIGN: This was a cross-sectional study. SETTING: The study was conducted at an outpatient clinic. PARTICIPANTS: Patients with adrenocortical adenomas (nonsecreting, n = 66; SH, n = 28) and 188 age- and sex-matched controls drawn from the general population participated in the study. MAIN OUTCOME MEASURES: Cortisol, 21-deoxycortisol, 11-deoxycortisol, 17-hydroxyprogesterone, androstenedione, dehydroepiandrosterone, T, progesterone, 11-deoxycorticosterone, and corticosterone in the basal condition and after a 1-24 ACTH test, and clinical data were measured. RESULTS: Patients with SH showed lower basal and 1-24 ACTH-stimulated levels of dehydroepiandrosterone and androstenedione than those with nonsecreting adenomas and controls. T was also lower in SH females. Receiver-operating characteristic curves showed that androgens had good accuracy in predicting SH (sensitivity and specificity were 71% and 76% for dehydroepiandrosterone and 69% and 61% for androstenedione, respectively). Increased cortisol and reduced dehydroepiandrosterone levels were independently associated with increased waist circumference. Cortisol was also independently associated with increased number of cardiovascular risk factors in SH patients. After 1-24 ACTH stimulation, the SH patients also showed increased production of 21-deoxycortisol and 11-deoxycorticosterone. CONCLUSIONS: Liquid chromatography-tandem mass spectrometry steroid profile performed for the first time in sera from patients with adrenocortical adenomas showed impaired secretion of several steroids in SH patients. This fingerprint can help in better characterizing the functional status of these tumors.

Determination of Synacthen(®) in dried blood spots for doping control analysis using liquid chromatography tandem mass spectrometry.

Dried blood spot (DBS) sampling, a technique used for taking whole blood samples dried on a filter paper, was initially reported in 1963 by Robert Guthrie. While the diagnostic analysis of metabolic disorders in newborns was the focus of investigations at that time, the number of established applications for preclinical drug development, toxicological studies, and therapeutic drug monitoring increased enormously in the last decades. As a consequence of speed, simplicity, and minimal invasiveness, DBS recommends itself as the preferential technique in sports drug testing. The present approach highlights for the first time the development of a screening assay for the analysis of the synthetic human adrenocorticotropic hormone tetracosactide hexaacetate (Synacthen(®)) in DBS using liquid chromatography tandem mass spectrometry. Highly purified sample extracts were obtained by an advanced sample preparation procedure including the addition of an internal standard (d8-tetracosactide) and immunoaffinity purification. The method's overall recovery was 27.6 %, and the assay's imprecision was calculated between 8.1 and 17.9 % for intraday and 12.9 to 20.5 % for interday measurements. Stability of the synthetic peptide in DBS was shown for at least 10 days at room temperature and presents a major benefit, since a rapid degradation in conventionally applied matrices such as urine or plasma is well known. With a limit of detection of 50 pg/mL, a detection window of several hours is expected considering reported steady-state plasma levels of 300 pg/mL after intramuscular application of Synacthen(®) Depot (1 mg). The analysis of authentic DBS samples within the scope of an administration study with 250 µg Synacthen(®) (short stimulation test) demonstrated the great potential of the developed assay to simplify the analysis of Synacthen(®) for doping control purposes.

Salivary cortisol and cortisone responses to tetracosactrin (synacthen).

BACKGROUND: To establish cutoff values for salivary liquid chromatography tandem mass spectroscopy cortisol and cortisone in defining adequate adrenocortical function during a standard synacthen test. METHODS: We compared salivary liquid chromatography tandem mass spectroscopy cortisol and cortisone responses to those of serum cortisol measured on the Roche E170 immunoassay analyser and the Abbott Architect i2000 before and 30 min and 60 min following 0.25 mg of intravenous synacthen. RESULTS: Correlations of salivary cortisol and cortisone were bimodal and linear, respectively. Based on these correlations, adequate salivary cortisol and cortisone responses to synacthen were extrapolated from a serum cortisol (Roche) cut-off of 550 nmol/L and defined as 15 nmol/L and 45 nmol/L, respectively. The Abbott method correlated well with the Roche but gave results that were about 20% lower than the Roche method. CONCLUSIONS: Measurement of salivary cortisol and cortisone responses offers an alternative to those of serum cortisol during a synacthen test in the investigation of adrenal hypofunction.

Primary vs secondary adrenal insufficiency: ACTH-stimulated aldosterone diagnostic cut-off values by tandem mass spectrometry.

OBJECTIVES: To validate the diagnostic utility of Cortrosyn(™) stimulated aldosterone in the differentiation of primary (PAI) and secondary adrenal insufficiency (SAI) and to evaluate the effect of urine sodium levels and posture on test performance. DESIGN: Cross-sectional study. METHODS: Healthy volunteers (HV; n = 46) and patients with PAI (n = 26) and SAI (n = 29) participated in the study. Testing included cortisol and aldosterone (by liquid-chromatography tandem mass spectrometry) measurements at baseline and 30 and 60 min after 250 µg Cortrosyn(™). Plasma corticotropin (ACTH), renin activity (PRA) and urine spot sodium as a proxy for 24-h urine sodium excretion were measured at baseline. The effect of a sitting or semifowlers posture was evaluated in healthy volunteers. RESULTS: A Cortrosyn(™)-stimulated aldosterone level of 5 ng/dl (0·14 nmol/l) had 88% sensitivity and positive predictive value and 89·7% specificity and negative predictive value for distinguishing PAI from SAI. Spot urine sodium levels showed a strong correlation with peak aldosterone levels (r = -0·55, P = 0·02, n = 18) in the SAI but not PAI or HV groups. Posture did not have a significant effect on results. CONCLUSIONS: Once diagnosed with adrenal insufficiency, a stimulated aldosterone value of 5 ng/dl (0·14 nmol/l) works well to differentiate PAI from SAI. However, clinicians should be aware of the possible effect of total body sodium as reflected by spot urine sodium levels on aldosterone results. A 24-h urine sodium measurement may be helpful in interpretation.

Detection of tetracosactide in plasma by enzyme-linked immunosorbent assay (ELISA).

As a synthetic analogue of adrenocorticotropic hormone (ACTH), tetracosactide is prohibited in sport by the World Anti-Doping Agency (WADA). An enzyme-linked immunosorbent assay (ELISA) method is proposed for detection of this drug in plasma. Since its structure corresponds to the 24 N-terminal of the 39 amino acids of the natural endogenous peptide ACTH, tetracosactide can be detected with a commercial ELISA kit for ACTH that uses antibodies, the epitopes of which are located in the 1-24 part of ACTH. However, an essential condition for detection specificity is the preliminary total clearance of endogenous ACTH in the plasma samples. This is achieved by a preparative step based on cation-exchange chromatography before ELISA. The method is specific and sensitive (LOD: 30 pg/mL) and may be used as a screening analysis in anti-doping control. The pre-analytical conditions are shown to be of the upmost importance and recommendations for blood collection (EDTA tubes), sample transport (4 °C) and plasma sample storage (-20 °C) are presented.

An LC-MS/MS method for steroid profiling during adrenal venous sampling for investigation of primary aldosteronism.

BACKGROUND: Steroid profiling for diagnosis of endocrine disorders featuring disordered production of steroid hormones is now possible from advances in liquid chromatography with tandem mass spectrometry (LC-MS/MS). Adrenal venous (AV) measurements of aldosterone and cortisol are a standard practice in the clinical work-up of primary aldosteronism, but do not yet take advantage of steroid profiling. METHODS: A novel LC-MS/MS based method was developed for simultaneous measurement of 15 adrenal steroids: aldosterone, corticosterone, 11-deoxycorticosterone, progesterone, pregnenolone, cortisone, cortisol, 11-deoxycortisol, 17-hydroxyprogesterone, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone-sulfate, 21-deoxycortisol, 18-oxocortisol and 18-hydroxycortisol. These were compared in peripheral venous (pV) and AV plasma from 70 patients undergoing AV sampling with and without cosyntropin stimulation. Aldosterone and cortisol levels measured by LC-MS/MS were compared with those measured by immunoassay. RESULTS: Reproducibility of measurements with coefficients of variation ≤10% as well as analytical sensitivity sufficient to measure low pV levels particularly of aldosterone demonstrate the utility of the assay for profiling adrenal steroids in primary aldosteronism. Method comparisons indicated assay and concentration dependent differences of cortisol and aldosterone concentrations measured by immunoassay and LC-MS/MS. Median AV/pV ratios of 11-deoxycortisol (53.0), 17-hydroxyprogesterone (33.4), pregnenolone (62.4), androstenedione (40.6) and dehydroepiandrosterone (33.3) were 2.9- to, 5.4-fold larger than those for cortisol (11.6), with additionally generally larger increases than for cortisol with than without cosyntropin stimulation. CONCLUSION: Our LC-MS/MS assay, in addition to improvements over existing immunoassay measurements of aldosterone and cortisol, offers profiling of 13 other adrenal steroids, providing a potentially useful method for the clinical work-up of patients with primary aldosteronism. In particular, the larger AV/pV ratios of several steroids compared to cortisol suggest more sensitive alternatives to the latter for assessing positioning of AV sampling catheters.

Effect of dexamethasone or synthetic ACTH administration on endogenous ACTH concentrations in healthy dogs.

OBJECTIVE: To determine the effects of dexamethasone or synthetic ACTH administration on endogenous ACTH concentrations in healthy dogs. ANIMALS: 10 healthy neutered dogs. PROCEDURES: Each dog received dexamethasone (0.01 mg/kg), synthetic ACTH (5 µg/kg), or saline (0.9% NaCl) solution (0.5 mL) IV at intervals of ≥ 30 days. Plasma endogenous ACTH concentrations were measured before (baseline; time 0) and 1, 8, 12, and 24 hours after drug administration; serum cortisol concentrations were measured before and 1 hour after synthetic ACTH and saline solution administration and 8 hours after dexamethasone administration. RESULTS: Analysis of serum cortisol concentrations confirmed effects of drug administration. Dexamethasone significantly decreased the endogenous ACTH concentration from the baseline value at both 8 and 12 hours. Synthetic ACTH administration significantly decreased the endogenous ACTH concentration from the baseline value at 8 hours. Saline solution administration had no significant effect on endogenous ACTH concentration. CONCLUSIONS AND CLINICAL RELEVANCE: Dexamethasone and synthetic ACTH administered IV at doses used routinely during testing for hyperadrenocorticism caused significant but transient reductions of endogenous ACTH concentrations in healthy dogs. Thus, a 2-hour washout period following ACTH stimulation testing before collection of samples for measurement of the endogenous ACTH concentration may be insufficient. Although this effect has not been verified in dogs with hyperadrenocorticism, these data suggested that samples for measurement of endogenous ACTH concentrations should be obtained before or > 8 hours after initiation of an ACTH stimulation test or before or > 12 hours after the start of a low-dose dexamethasone suppression test.

Validation of a low-dose adrenocorticotropic hormone stimulation test in healthy neonatal foals.

OBJECTIVE: To determine the lowest ACTH dose that would induce a significant increase in serum cortisol concentration and identify the time to peak cortisol concentration in healthy neonatal foals. DESIGN: Prospective randomized crossover study. ANIMALS: 11 healthy neonatal foals. PROCEDURES: Saline (0.9% NaCl) solution or 1 of 4 doses (0.02, 0.1, 0.25, and 0.5 µg/kg [0.009, 0.045, 0.114, and 0.227 µg/lb]) of cosyntropin (synthetic ACTH) was administered IV. Serum cortisol concentrations were measured before and 10, 20, 30, 60, 90, 120, 180, and 240 minutes after administration of cosyntropin or saline solution; CBCs were performed before and 30, 60, 120, and 240 minutes after administration. RESULTS: Serum cortisol concentration was significantly increased, compared with baseline, by 10 minutes after cosyntropin administration at doses of 0.1, 0.25, and 0.5 µg/kg. Serum cortisol concentration peaked 20 minutes after administration of cosyntropin at doses of 0.02, 0.1, and 0.25 µg/kg, with peak concentrations 1.7, 2.0, and 1.9 times the baseline concentration, respectively. Serum cortisol concentration peaked 30 minutes after cosyntropin administration at a dose of 0.5 µg/kg, with peak concentration 2.2 times the baseline concentration. No significant differences were detected among peak serum cortisol concentrations obtained with cosyntropin administration at doses of 0.25 and 0.5 µg/kg. Cosyntropin administration significantly affected the lymphocyte count and the neutrophil-to-lymphocyte ratio. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in healthy neonatal foals, the lowest dose of cosyntropin to result in significant adrenal gland stimulation was 0.25 µg/kg, with peak cortisol concentration 20 minutes after cosyntropin administration.

Simultaneous quantification and qualification of synacthen in plasma.

Tetracosactide (Synacthen), a synthetic analogue of adrenocorticotropic hormone (ACTH), can be used as a doping agent to increase the secretion of glucocorticoids by adrenal glands. The only published method for anti-doping control of this drug in plasma relies on purification by immunoaffinity chromatography and LC/MS/MS analysis. Its limit of detection is 300 pg/mL, which corresponds to the peak value observed 12 h after 1 mg Synacthen IM administration. We report here a more sensitive method based on preparation of plasma by cation exchange chromatography and solid-phase extraction and analysis by LC/MS/MS with positive-mode electrospray ionization using 7-38 ACTH as internal standard. Identification of Synacthen was performed using two product ions, m/z 671.5 and m/z 223.0, from the parent [M + 5H](5+) ion, m/z 587.4. The recovery was estimated at 70%. A linear calibration curve was obtained from 25 to 600 pg/mL (R² > 0.99). The lower limit of detection was 8 pg/mL (S/N > 3). The lower limit of quantification was 15 pg/mL (S/N > 10; CV% < 20%). The performance of the method was illustrated by an 8-h kinetic analysis of plasma samples from nine subjects submitted to IM injections of either Synacthen® (five subjects) or Synacthen® Depot, the slow-release form of the drug (four subjects). Concentrations of Synacthen between 16 and 310 pg/mL were observed. A sensitive method for quantitation of Synacthen in plasma is proposed for anti-doping control analyses.

Physiologic variance of corticotropin affects diagnosis in adrenal vein sampling.

OBJECTIVE: Differentiating unilateral form from bilateral is a critical diagnostic step in primary aldosteronism (PA), for which adrenal vein sampling (AVS) is accepted to be the most reliable. However, variance of corticotropin could affect the diagnosis in AVS. DESIGN AND METHODS: We conducted simultaneous bilateral AVS on ten biochemically diagnosed PA cases, and used the aldosterone-to-cortisol ratio (A/C) of the samples for the diagnosis. The diagnosis by AVS after a low-dose (0.1 microg) ACTH stimulation, which can provoke maximum-physiologic corticotropic response, was compared with those before the stimulation and after the standard-dose (250 microg) ACTH stimulation. RESULTS: In half of the cases, the low-dose pre-stimulation affected the diagnosis. In four out of ten cases, the side-to-side ratios of A/C were changed in the basal/low-dose/standard-dose AVS as 6.62/2.46/0.63, 2.13/0.41/0.14, 1.88/2.38/2.40, and 1.96/2.27/1.90 respectively. In three out of ten cases, the adrenal vein to the matching inferior vena cava ratio of A/C was also changed across 1, the cut-off to indicate suppression of aldosterone secretion. Additionally, the confirmation of successful sampling was difficult in five out of ten and two out of ten cases of the basal and low-dose AVS respectively, whereas it was easy in all the cases of the standard-dose AVS. CONCLUSIONS: The diagnosis in the basal AVS could be affected by the physiologic fluctuation of ACTH at relatively high prevalence. The basal AVS would be unreliable to differentiate two forms of PA.

Cortisol response to ACTH stimulation correlates with blood interleukin 6 concentration in healthy humans.

OBJECTIVE: Interleukin 6 (IL6) has the ability to influence each level of the hypothalamo-pituitary-adrenocortical (HPA) axis. The aim of the study was to test whether IL6 concentration correlates with the adrenal cortex response to ACTH in healthy humans. We postulated that higher basal IL6 concentration would be associated with the higher cortisol response to the stimulation. DESIGN AND METHODS: Basal IL6 concentration was measured and a low dose (1 microg) ACTH test was performed to assess cortisol response. Twenty-seven apparently healthy subjects (11 male, 16 female, mean age 31.1 years, age range 22-47 years) were included in the study. RESULTS: Data are presented as mean+/-S.E.M. Basal IL6 level was 0.84+/-0.10 pg/ml. Basal cortisol was 351.9+/-18.3 nmol/l. Maximal cortisol during synacthen test was 653.0+/-20.6 nmol/l. Maximal cortisol increment was 301.1+/-20.0 nmol/l. IL6 concentration was not correlated with basal or maximal cortisol concentration, but correlated significantly with cortisol increment (r=0.63, 95% confidence interval) 0.42-0.83). CONCLUSIONS: In our study, we found that higher basal IL6 concentration is associated with the higher cortisol response to ACTH stimulation. Based on previous research and our data, IL6, even in low concentrations and under physiologic conditions, modulates adrenal cortex responsivity to ACTH. Therefore, it seems that immune modulation of HPA axis is also present under physiologic and not only pathologic conditions.

Determination of Synacthen in human plasma using immunoaffinity purification and liquid chromatography/tandem mass spectrometry.

Synacthen is a synthetic analogue to human adrenocorticotropin, which plays an important physiological role by stimulating production of cortisol. In sports, corticosteroids as well as releasing factors (corticotropins) are prohibited according to the regulations of the World Anti-Doping Agency, and the misuse of Synacthen has been reported several times. Hence, an assay enabling the detection of Synacthen in doping control samples has been developed using immunoaffinity chromatographic isolation of Synacthen from human plasma combined with a concentration of collected fractions using solid-phase extraction. Unambiguous determination of the target analyte was accomplished using microbore liquid chromatography/electrospray ionization tandem mass spectrometry. Diagnostic product ions such as m/z 223 were characterized using high-resolution/high-accuracy Orbitrap mass spectrometry and employed for triple quadrupole MS/MS analysis. The established assay requiring 2 mL of plasma allowed a lower limit of detection (LLOD) at 100 fmol/mL, a recovery of 97% and a precision at the LLOD < 20%. Authentic plasma samples obtained from a patient undergoing a standard short Synacthen test were used to prove the applicability of the developed procedure.

Intramuscular administration of a low dose of ACTH for ACTH stimulation testing in dogs.

OBJECTIVE: To compare adrenal gland stimulation achieved following administration of cosyntropin (5 microg/kg [2.3 microg/lb]) IM versus IV in healthy dogs and dogs with hyperadrenocorticism. DESIGN: Clinical trial. Animals-9 healthy dogs and 9 dogs with hyperadrenocorticism. PROCEDURES: In both groups, ACTH stimulation was performed twice. Healthy dogs were randomly assigned to receive cosyntropin IM or IV first, but all dogs with hyperadrenocorticism received cosyntropin IV first. In healthy dogs, serum cortisol concentration was measured before (baseline) and 30, 60, 90, and 120 minutes after cosyntropin administration. In dogs with hyperadrenocorticism, serum cortisol concentration was measured before and 60 minutes after cosyntropin administration. RESULTS: In the healthy dogs, serum cortisol concentration increased significantly after administration of cosyntropin, regardless of route of administration, and serum cortisol concentrations after IM administration were not significantly different from concentrations after IV administration. For both routes of administration, serum cortisol concentration peaked 60 or 90 minutes after cosyntropin administration. In dogs with hyperadrenocorticism, serum cortisol concentration was significantly increased 60 minutes after cosyntropin administration, compared with baseline concentration, and concentrations after IM administration were not significantly different from concentrations after IV administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in healthy dogs and dogs with hyperadrenocorticism, administration of cosyntropin at a dose of 5 microg/kg, IV or IM, resulted in equivalent adrenal gland stimulation.

Profile, mean residence time of ACTH and cortisol responses after low and standard ACTH tests in healthy volunteers.

OBJECTIVE: No consensus exists until now about the suitable dose of tetracosactin in the ACTH stimulation test for detecting adrenal insufficiency. Our aim was to characterize both the ACTH(1-24) and the cortisol profiles after standard high-dose test (250 microg) (HDT) and low-dose test (1 microg) (LDT) in healthy subjects in order to provide a deeper knowledge about the relationship between stimulus and response. DESIGN AND PATIENTS: ACTH tests were performed in 10 healthy volunteers (five men, five women) with at least 1 week of difference. MEASUREMENTS: Plasma ACTH(1-24) and ACTH(1-39) and serum cortisol were measured before tetracosactin i.v. injection and at 5, 15, 30, 45, 60, 75 and 90 min after stimulus. Area under the curve (AUC) of ACTH(1-24) and cortisol, as well as mean residence time (MRT) for ACTH(1-24) were calculated in both tests. RESULTS: Elimination of ACTH(1-24) was faster in HDT than in LDT (MRTs of 0.14 vs 0.37, respectively, P = 0.008), but plasma concentrations were higher up to 60 min cortisol production in HDT reaching a higher maximum concentration (Cmax: 1144 vs 960 nmol/l) but delayed in time (75 vs 52.5 min). No significant relationship was observed between AUC or Cmax of ACTH(1-24) and AUC, Cmax and increment of cortisol in any of the tests. However, a negative correlation of basal cortisol values was observed with relative cortisol increment (HDT: r = 0.77 P = 0.009; LDT: r = 0.94 P < 0.0001), but not so with Cmax (HDT: r = 0.22 P = 0.55; LDT: r = 0.57 P = 0.09). CONCLUSIONS: The elimination rate of ACTH in healthy volunteers was significantly lower in LDT than in HDT, but cortisol production rate appears to be identical in both tests, so that a maximum adrenal stimulation seems to exist. The use of LDT may be more adequate, although data from patients need studying.