Impaired aldosterone response to ACTH without hypoaldosteronism: An unrecognized secretory pattern in search of clinical implications.

CONTEXT: Aldosterone has been recently characterized as a 'stress hormone'. Stress per se elicits a sizable rise in aldosterone secretion, which could be replicated by the administration of a low dose (0.03-1 µg, IV) of adrenocorticotropic hormone (ACTH). Whether or not the aldosterone response to ACTH could be selectively impaired, that is, in association with intact cortisol response, is presently unknown. OBJECTIVE: To determine whether or not the aldosterone response to low dose of ACTH is impaired in subjects referred to assess the hypothalamic-pituitary-adrenal axis (HPA). DESIGN: Retrospective analysis. SETTING: Outpatient referral endocrine day care centre. PATIENTS: One hundred and ninety-five consecutive subjects who underwent the low dose (1 µg) ACTH test, in whom decreased cortisol reserve was suspected due to former/present glucocorticoid excess, pituitary disease or/and unexplained weakness. MAIN OUTCOME MEASURES: The outcome was the detection of lack of aldosterone response, defined as a rise <111 pmol/l. RESULTS: In all, 46/195 subjects had subnormal aldosterone response as compared with 52/195 subjects showing diminished cortisol response. Nine subjects had combined deficient aldosterone and cortisol response. In the 37 subjects with isolated subnormal aldosterone response common associations were the use of exogenous glucocorticoids, mostly prednisone (n = 16); former Cushing disease (n = 2); nonfunctioning pituitary adenoma (n = 8); hypothyroidism (n = 11); the use of statins (n = 11), angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (n = 6), sex steroids in transgenders and orthostatic hypotension (n = 3). Twenty-seven percent (25/93) of the subjects with recent exposure to glucocorticoids had impaired aldosterone response to ACTH. CONCLUSION: Blunted aldosterone response to ACTH in the absence of hypoaldosteronism was seen in ~27% of subjects referred for HPA assessment using the low dose 1 µg ACTH test. Exposure to glucocorticoid excess was often linked to this impairment, independent of the cortisol response to ACTH.

Low-dose ACTH test for evaluation of hypothalamus-pituitary-adrenal axis preoperatively and 3-month follow-up in non-functioning pituitary adenomas.

BACKGROUND: Peri-operative glucocorticoids are routinely administered to patients undergoing trans-sphenoidal surgery for non-functional pituitary adenomas (NFPA) irrespective of hypothalamus-pituitary-adrenal (HPA) axis status. PURPOSE: Evaluation of HPA axis before and 12 weeks after endoscopic trans-sphenoidal adenomectomy (E-TSA) utilizing low-dose (1 µg) ACTH stimulation test (LDACTH) to determine the need for glucocorticoid administration in patients with NFPA. We also determined the factors that can predict occurrence of hypocortisolism at 12 weeks after surgery. METHODS: Sixty-three consecutive patients with NFPA requiring surgical excision were enrolled in this study. Glucocorticoids were administered to patients with demonstrable hypocortisolism [preoperative peak cortisol < 16 µg/dL during LDACTH test, postoperative day 3 (POD-3) 0800 hrs Cortisol < 8 µg/dL or stimulated cortisol (LDACTH) < 16 µg/dL at 12 weeks]. RESULTS: Hypocortisolism was present in 43 patients (68.2%) pre-operatively and persisted in 33 patients (52.4%) on POD-3. Thirty-three patients (52.4%) had hypocortisolism at 12 weeks after surgery. Eleven patients (17.4%) did not require glucocorticoids during the entire study period and 30 patients (47.6%) did not require glucocorticoids after 3 months. None of the patients developed adrenal crisis during the study. Hypocortisolism on the third post-operative day was the single significant predictor of hypocortisolism at 12 weeks after the surgery. There was a significant correlation between POD-3 0800 hrs cortisol ≥ 8µg/dL and stimulated cortisol (LDACTH) ≥16µg/dL at 12 weeks (r = 0.62, p < 0.0001). POD-3 0800 hrs cortisol ≥ 8 µg/dL had 73% sensitivity and 79% specificity in predicting eucortisolism at 12 weeks. CONCLUSIONS: HPA function is preserved in significant proportion of NFPA patients undergoing E-TSA. Perioperative glucocorticoids should be given only in patients with demonstrable preoperative hypocortisolism on 1 µg ACTH test. Postoperative day 3 0800 hrs cortisol is a reasonable predictor of HPA axis status at 12 weeks after surgery.

Adrenocorticotropic hormone elicits gonadotropin secretion in premenopausal women.

STUDY QUESTION: Does adrenocorticotropic hormone (ACTH) induce gonadotropin release in premenopausal women? SUMMARY ANSWER: Administration of ACTH stimulates gonadotropin release, most likely by stimulation of the production of cortisol, in premenopausal women. WHAT IS KNOWN ALREADY: In animal models, acute activation of the hypothalamic-pituitary-adrenal (HPA) axis has been shown to induce gonadotropin release in the presence of sufficiently high estrogen levels. However, it is unknown whether the HPA axis has a similar influence on gonadotropin release in humans. STUDY DESIGN, SIZE, DURATION: This study had a mixed factorial design. A total of 60 healthy female participants participated in the experimental study. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study sample comprised three distinct hormonal-based populations according to their levels of progesterone (PROG) and estradiol (E2): (i) low-PROG-low-E2, (ii) low-PROG-high-E2 and (iii) high-PROG-high-E2 women. A low dose (1 µg) of ACTH was administered to all study participants. Serum steroid and gonadotropin concentrations were measured prior to, and at 30 and 90 minutes after, intravenous ACTH administration. MAIN RESULTS AND THE ROLE OF CHANCE: Mean serum cortisol levels increased significantly following ACTH administration in all groups (P < 0.001). Similarly, the serum levels of 17-OH-PROG, androstenedione, dehydroepiandrosterone and testosterone increased significantly in all groups (P < 0.01). The low-PROG-high-E2 and high-PROG-high-E2 groups exhibited a significant increase in LH and FSH levels (P < 0.001), whereas the low-PROG-low-E2 group demonstrated blunted LH and FSH responses to ACTH administration (P < 0.05). LIMITATIONS, REASONS FOR CAUTION: Testing was performed during the luteal phase of the natural menstrual cycle. Testing during the follicular phase might have elicited premature, or more pronounced, LH surges in response to ACTH administration. WIDER IMPLICATIONS OF THE FINDINGS: Our findings suggest a novel mechanism by which the adrenal cortex functions as a mediator of gonadotropin release. These findings contribute to a greater understanding of the influence of acute stress on reproductive endocrinology. STUDY FUNDING/COMPETING INTERESTS: Funding was received from the Erasmus University Medical Center. The authors have no conflicts of interest. TRIAL REGISTRATION NUMBER: EudraCT Number 2012-005640-14.

Should we routinely assess hypothalamic-pituitary-adrenal axis in pediatric patients with Prader-Willi syndrome?

Background: It has been reported that central adrenal insufficiency (CAI) in pediatric patients (pts) with Prader-Willi syndrome (PWS) may be a potential cause of their sudden death. In addition, the risk of CAI may increase during treatment with recombinant human growth hormone (rhGH). Objective: To prevent both over- and undertreatment with hydrocortisone, we evaluated the prevalence of CAI in a large multicenter cohort of pediatric pts with PWS analyzing adrenal response in the low-dose ACTH test (LDAT) and/or the glucagon stimulation test (GST) and reviewing the literature. Methods: A total of 46 pts with PWS were enrolled to the study, including 34 treated with rhGH with a median dose of 0.21 mg/kg/week. LDAT was performed in 46 pts, and GST was carried out in 13 pts. Both tests were conducted in 11 pts. The tests began at 8:00 a.m. Hormones were measured by radioimmunoassays. Serum cortisol response >181.2 ng/mL (500 nmol/L) in LDAT and >199.3 ng/mL (550 nmol/L) in GST was considered a normal response. Additionally, cortisol response delta (the difference between baseline and baseline) >90 ng/mL and doubling/tripling of baseline cortisol were considered indicators of normal adrenal reserve. Results: Three GSTs were not diagnostic (no hypoglycemia obtained). LDAT results suggested CAI in four pts, but in two out of four pts, and CAI was excluded in GST. GST results suggested CAI in only one patient, but it was excluded in LDAT. Therefore, CAI was diagnosed in 2/46 pts (4.3%), 1 treated and 1 untreated with rhGH, with the highest cortisol values of 162 and 175 ng/dL, but only in one test. However, in one of them, the cortisol delta response was >90 ng/mL and peak cortisol was more than tripled from baseline. Finally, CAI was diagnosed in one patient treated with rhGH (2.2%). Conclusion: We present low prevalence of CAI in pediatric pts with PWS according to the latest literature. Therefore, we do not recommend to routinely screen the function of the hypothalamic-pituitary-adrenal axis (HPAA) in all pts with PWS, both treated and untreated with rhGH. According to a review of the literature, signs and symptoms or low morning ACTH levels suggestive of CAI require urgent and appropriate diagnosis of HPAA by stimulation test. Our data indicate that the diagnosis of CAI should be confirmed by at least two tests to prevent overtreatment with hydrocortisone.

Comparison of a combination test (1 µg ACTH test plus glucagon test) versus 1 µg ACTH test and glucagon test in the evaluation of the hypothalamic-pituitary-adrenal axis in patients with pituitary disorders.

OBJECTIVE: To investigate whether a combination of the low-dose (1 µg) adrenocorticotropin (ACTH) stimulation test and glucagon stimulation test (GST) could overcome the problem of equivocal results with the GST or ACTH test alone in patients with pituitary disorders. METHODS: The study included 41 adult patients with pituitary disorders and 20 healthy subjects who underwent evaluation of cortisol response to ACTH, GST, and a combination of both tests. Blood samples for cortisol measurement were obtained at baseline and 30, 60, 90, and 120 minutes after intravenous administration of ACTH 1 µg and 90, 120, 150, 180, 210, and 240 minutes after subcutaneous injection of glucagon 1 mg. The combination test was performed by injecting ACTH 1 µg at the 180-minute time point of the GST, with blood samples for cortisol measurement obtained at 210 and 240 minutes. RESULTS: Overall, 28 patients with normal cortisol response to both tests also had a normal cortisol response to the combination test. Ten patients with adrenal insufficiency in both tests also had adrenal insufficiency in the combination test, including a patient who had a peak cortisol value of 12.4 µg/dL (which is the cutoff value for the combination test). Two patients with adrenal insufficiency in the ACTH stimulation test and one patient with adrenal insufficiency in the GST had normal cortisol responses to the combination test. CONCLUSION: By using an appropriate cutoff value, the combination test may offer additional information in patients with equivocal results in the GST and ACTH stimulation test.

Accuracy of the Low-Dose ACTH Stimulation Test for Adrenal Insufficiency Diagnosis: A Re-Assessment of the Cut-Off Value.

BACKGROUND: The clinical practice shows that many low-dose ACTH-stimulation tests have a false positive result. The aim of the study was to determine the diagnostic accuracy of a low-dose ACTH-stimulation test in the diagnosis of adrenal insufficiency and to define its optimal cut-off. METHODS: We analyzed data from 103 patients undergoing 1 µg ACTH-stimulation test. Four patients had adrenal insufficiency (AI) upon follow up: Two primary, and two secondary AI. Cortisol serum levels were evaluated at time 0, 20', and 30' after the injection of 1 µg i.v. of ACTH. The sensitivity, specificity, accuracy, and positive and negative predictive values of the test were calculated for both 20' and 30' sampling. The receiver operating characteristic (ROC) curve was obtained to assess the sensitivity and specificity of low-dose ACTH-stimulation test in the diagnosis of adrenal insufficiency at different cut-off values. RESULTS: Considering 500 nmol/L as the standard cut-off value, low-dose ACTH stimulation test showed a 100% sensitivity and a 67.3% specificity, with a high rate of false positive results. ROC curve analysis showed that the cut-off of 401.5 nmol/L is the best compromise between sensitivity (100%) and specificity (93.9%). CONCLUSIONS: By using a cut-off value of 401.5 nmol/L for the low-dose ACTH stimulation test, the number of false positive patients decreased significantly, but the sensitivity remained high.

Comparison of a combination test (1 µg ACTH test plus glucagon test) versus 1 µg ACTH test and glucagon test in the evaluation of the hypothalamic-pituitary-adrenal axis in patients with pituitary disorders

ABSTRACT Objective To investigate whether a combination of the low-dose (1 µg) adrenocorticotropin (ACTH) stimulation test and glucagon stimulation test (GST) could overcome the problem of equivocal results with the GST or ACTH test alone in patients with pituitary disorders. Subjects and methods The study included 41 adult patients with pituitary disorders and 20 healthy subjects who underwent evaluation of cortisol response to ACTH, GST, and a combination of both tests. Blood samples for cortisol measurement were obtained at baseline and 30, 60, 90, and 120 minutes after intravenous administration of ACTH 1 μg and 90, 120, 150, 180, 210, and 240 minutes after subcutaneous injection of glucagon 1 mg. The combination test was performed by injecting ACTH 1 µg at the 180-minute time point of the GST, with blood samples for cortisol measurement obtained at 210 and 240 minutes. Results Overall, 28 patients with normal cortisol response to both tests also had a normal cortisol response to the combination test. Ten patients with adrenal insufficiency in both tests also had adrenal insufficiency in the combination test, including a patient who had a peak cortisol value of 12.4 µg/dL (which is the cutoff value for the combination test). Two patients with adrenal insufficiency in the ACTH stimulation test and one patient with adrenal insufficiency in the GST had normal cortisol responses to the combination test. Conclusion By using an appropriate cutoff value, the combination test may offer additional information in patients with equivocal results in the GST and ACTH stimulation test.