Dehydroepiandrosterone, 17alpha-hydroxyprogesterone and aldosterone responses to the low-dose (1 micro g) ACTH test in subjects with preclinical adrenal autoimmunity

Successful Treatment of Infertility in a Patient with Probable 17 Hydroxylase Deficiency and Particularities of Association with Adrenal Autoimmunity—A Case Report and Review of the Literature

Congenital adrenal hyperplasia (CAH) due to 17-hydroxylase deficiency (17OHD) is a rare disease accounting for less than 1% of cases of CAH. In female patients, fertility is severely affected mainly due to constantly increased progesterone affecting endometrium receptivity and implantation. The optimal treatment for infertility in these patients is not clearly established, with only a few recent case reports of successful pregnancies available in the literature. Hereby, we present the case of an infertile female patient with 17OHD who obtained pregnancy through an in vitro fertilization (IVF) freeze-all strategy and particularities of association with adrenal autoimmunity. A 32-year-old infertile female patient was referred for infertility evaluation and treatment. She had normal sex development and menstrual history with oligomenorrhea alternating with normal menstrual cycles. During the evaluation, a reduced ovarian reserve and obstruction of the left fallopian tube were identified, and IVF treatment was recommended. During a controlled ovarian stimulation for IVF, increased values of serum progesterone were observed; thus, all the embryos were frozen and additional tests were performed. Increased values of 17-hydroxyprogesteron, 11-deoxycorticosteron, and adrenocorticotropic hormones in association with low basal and stimulated serum cortisol, testosterone, androstenedione, and dehydroepiandrosterone sulfate were found, supporting the presence of 17OHD. She started treatment with oral hydrocortisone given at 20 mg/day but, because follicular phase serum progesterone remained high, hydrocortisone was replaced by an oral dexamethasone treatment of 0.5 mg/day, followed by the normalization of serum progesterone. A thawed blastocyst was transferred after preparation with oral estradiol at 6 mg/day and intravaginal progesterone at 600 mg/day under continuous suppression of endogenous progesterone production with a gonadotropin-releasing hormone agonist and oral dexamethasone. The patient became pregnant and delivered two healthy girls at term. One year after delivery, the presence of 21-hydroxylase antibodies was detected, which might explain the particularities of adrenal steroids in our patient. Our case report demonstrates that a patient with 17OHD can become pregnant through IVF and the transfer of thawed embryos in a subsequent cycle under continuous suppression of adrenal and ovarian progesterone production.

Investigation of the Hypothalamo-pituitary-adrenal (HPA) axis: a contemporary synthesis

The hypothalamo-pituitary-adrenal (HPA) axis is one of the main components of the stress system. Maintenance of normal physiological events, which include stress responses to internal or external stimuli in the body, depends on appropriate HPA axis function. In the case of severe cortisol deficiency, especially when there is a triggering factor, the patient may develop a life-threatening adrenal crisis which may result in death unless early diagnosis and adequate treatment are carried out. The maintenance of normal physiology and survival depend upon a sufficient level of cortisol in the circulation. Life-long glucocorticoid replacement therapy, in most cases meeting but not exceeding the need of the patient, is essential for normal life expectancy and maintenance of the quality of life. To enable this, the initial step should be the correct diagnosis of adrenal insufficiency (AI) which requires careful evaluation of the HPA axis, a highly dynamic endocrine system. The diagnosis of AI in patients with frank manifestations is not challenging. These patients do not need dynamic tests, and basal cortisol is usually enough to give a correct diagnosis. However, most cases of secondary adrenal insufficiency (SAI) take place in a gray zone when clinical manifestations are mild. In this situation, more complicated methods that can simulate the response of the HPA axis to a major stress are required. Numerous studies in the assessment of HPA axis have been published in the world literature. In this review, the tests used in the diagnosis of secondary AI or in the investigation of suspected HPA axis insufficiency are discussed in detail, and in the light of this, various recommendations are made.

Impact of Adrenal Function on Hemostasis/Endothelial Function in Patients Undergoing Surgery

Context

Glucocorticoids regulate hemostatic and endothelial function, and they are critical for adaptive functions during surgery. No data regarding the impact of adrenal function on hemostasis and endothelial function in the perioperative setting are available.

Objective

We assessed the association of adrenal response to adrenocorticotropic hormone (ACTH) and markers of endothelial/hemostatic function in surgical patients.

Methods

This prospective observational study, conducted at a tertiary care hospital, included 60 patients (35 male/25 female) undergoing abdominal surgery. Adrenal function was evaluated by low-dose ACTH stimulation test on the day before, during, and the day after surgery. According to their stimulated cortisol level (cutoff ≥ 500 nmol/L), patients were classified as having normal hypothalamic-pituitary-adrenal (HPA)-axis function (nHPA) or deficient HPA-axis function (dHPA). Parameters of endothelial function (soluble vascular cell adhesion molecule-1, thrombomodulin) and hemostasis (fibrinogen, von Willebrand factor antigen, factor VIII [FVIII]) were measured during surgery.

Results

Twenty-one patients had dHPA and 39 had nHPA. Compared with nHPA, patients with dHPA had significantly lower peak cortisol before (median 568 vs 425 nmol/L, P < 0.001) and during (693 vs 544 nmol/L, P < 0.001) surgery and lower postoperative hemoglobin levels (116 g/L vs 105 g/L, P = 0.049). FVIII was significantly reduced in patients with dHPA in uni- and multivariable analyses; other factors displayed no significant differences. Coagulation factors/endothelial markers changed progressively in relation to stimulated cortisol levels and showed a turning point at cortisol levels between 500 and 600 nmol/L.

Conclusions

Patients with dHPA undergoing abdominal surgery demonstrate impaired hemostasis which can translate into excessive blood loss.

Serum dehydroepiandrosterone sulfate in assessing the integrity of the hypothalamic-pituitary-adrenal axis

Objective

To evaluate the relationship between age- and gender-adjusted dehydroepiandrosterone sulfate (DHEA-S) levels and low-dose adrenocorticotropic hormone (ACTH) stimulation in assessing the integrity of the hypothalamic-pituitary-adrenal (HPA) axis, in patients who were at risk of HPA insufficiency, including those currently being treated with glucocorticoids.

Methods

Forty-six participants with a suspicion of secondary adrenal insufficiency were recruited from the Diabetes and Endocrinology Clinic at Ramathibodi Hospital, Mahidol University, Bangkok. Low-dose (1 μg) ACTH stimulation was performed in every participants, and serum DHEA-S was measured at baseline before ACTH injection.

Results

Individuals with normal age- and gender-specific DHEA-S levels had baseline serum cortisol and peak cortisol levels higher than those with reduced DHEA-S. Normal age- and gender-specific DHEA-S levels predicted intact HPA function with a sensitivity of 87.1%, a specificity of 86.7%, a positive predictive value of 93.1%, and a negative predictive value of 76.5%. To account for the age and gender dependency of DHEA-S, the DHEA-S ratio was calculated by measured DHEA-S divided by the lower limit of the respective reference range for all participants. A DHEA-S ratio of more than 1.78 had 100% sensitivity regarding intact HPA function. Area under the receiver operating characteristic [ROC] curve was 0.920. (95% CI, 0.844–0.997).

Conclusion

Normal age- and gender-specific DHEA-S level or a DHEA-S ratio of more than 1.78 are valuable markers of HPA integrity. Serum DHEA-S may be a candidate for a less costly approach where ACTH stimulation is unavailable.

A Comparison of Salivary Steroid Levels during Diagnostic Tests for Adrenal Insufficiency

Numerous diagnostic tests are used to evaluate the hypothalamic-pituitary-adrenal axis (HPA axis). The gold standard is still considered the insulin tolerance test (ITT), but this test has many limitations. Current guidelines therefore recommend the Synacthen test first when an HPA axis insufficiency is suspected. However, the dose of Synacthen that is diagnostically most accurate and sensitive is still a matter of debate. We investigated 15 healthy men with mean/median age 27.4/26 (SD±4.8) years, and mean/median BMI (body mass index) 25.38/24.82 (SD±3.2) kg/m2. All subjects underwent 4 dynamic tests of the HPA axis, specifically 1 μg, 10 μg, and 250 μg Synacthen (ACTH) tests and an ITT. Salivary cortisol, cortisone, pregnenolone, and DHEA (dehydroepiandrosterone) were analysed using liquid chromatography-tandem mass spectrometry. During the ITT maximum salivary cortisol levels over 12.5 nmol/l were found at 60 minutes. Maximum cortisol levels in all of the Synacthen tests were higher than this; however, demonstrating that sufficient stimulation of the adrenal glands was achieved. Cortisone reacted similarly as cortisol, i.e. we did not find any change in the ratio of cortisol to cortisone. Pregnenolone and DHEA were higher during the ITT, and their peaks preceded the cortisol peak. There was no increase of pregnenolone or DHEA in any of the Synacthen tests. We demonstrate that the 10 μg Synacthen dose is sufficient stimulus for testing the HPA axis and is also a safe and cost-effective alternative. This dose also largely eliminates both false negative and false positive results.

Therapy of adrenal insufficiency: an update

Adrenal insufficiency may be caused by the destruction or altered function of the adrenal gland with a primary deficit in cortisol secretion (primary adrenal insufficiency) or by hypothalamic-pituitary pathologies determining a deficit of ACTH (secondary adrenal insufficiency). The clinical picture is determined by the glucocorticoid deficit, which may in some conditions be accompanied by a deficit of mineralcorticoids and adrenal androgens. The substitutive treatment is aimed at reducing the signs and symptoms of the disease as well as at preventing the development of an addisonian crisis, a clinical emergency characterized by hypovolemic shock. The oral substitutive treatment should attempt at mimicking the normal circadian profile of cortisol secretion, by using the lower possible doses able to guarantee an adequate quality of life to patients. The currently available hydrocortisone or cortisone acetate preparations do not allow an accurate reproduction of the physiological secretion pattern of cortisol. A novel dual-release formulation of hydrocortisone, recently approved by EMEA, represents an advancement in the optimization of the clinical management of patients with adrenal insufficiency. Future clinical trials of immunomodulation or immunoprevention will test the possibility to delay (or prevent) the autoimmune destruction of the adrenal gland in autoimmune Addison's disease.

Measurements of serum DHEA and DHEA sulphate levels improve the accuracy of the low-dose cosyntropin test in the diagnosis of central adrenal insufficiency

BACKGROUND AND OBJECTIVES

The diagnosis of central adrenal insufficiency (AI) continues to be challenging, especially when it is partial. We have recently demonstrated the value of measuring serum dehydroepiandrosterone sulfate (DHEA-S) in establishing the diagnosis of central AI. The current investigation examined the added value of measuring serum dehydroepiandrosterone (DHEA) levels during low-dose (1 μg) cosyntropin (LDC) stimulation in patients suspected to have central AI.

METHODS

Baseline and LDC-stimulated cortisol, DHEA, and DHEA-S were measured preoperatively in 155 consecutive patients with pituitary masses and 63 healthy subjects. Hypothalamic-pituitary adrenal (HPA) function was normal (NL-HPA) in 97 of the patients and was impaired (impaired HPA) in 58 patients. Patients with NL-HPA underwent surgical removal of the sellar masses and received no glucocorticoids before, during, or after surgery.

RESULTS

Baseline and LDC-stimulated serum cortisol, DHEA, and DHEA-S in patients with NL-HPA were similar to those of normal subjects. In contrast, patients with impaired HPA had lower baseline and LDC-stimulated serum cortisol, DHEA, and DHEA-S levels. There were 18 subjects in the latter group whose LDC-stimulated serum cortisol levels were greater than 18.0 μg/dl. In those 18 subjects, baseline and LDC-stimulated DHEA and DHEA-S levels were similar to the whole group of patients with impaired HPA function. The molar ratio of cortisol to DHEA did not change with LDC stimulation in normal subjects and those with NL-HPA. In contrast, patients with impaired HPA had a higher baseline cortisol to DHEA molar ratio that increased further with LDC stimulation.

CONCLUSIONS

Patients with impaired HPA function have a more severe loss in DHEA secretion than that of glucocorticoids. Measurements of serum DHEA levels during LDC simulation provide additional valuable information that improves the diagnostic accuracy of LDC in patients suspected to have central AI. We recommend the inclusion of DHEA and DHEA-S measurements in the laboratory assessment of HPA function.

Changes in steroid concentrations with the timing of corticotropin stimulation testing in participants with adrenal sufficiency

OBJECTIVE

To determine whether the time of day at which corticotropin stimulation testing is performed influences the steroid concentrations observed in persons with normal adrenal function.

METHODS

In this retrospective, secondary analysis, participants with normal adrenal function were studied to determine whether the time of corticotropin stimulation testing influenced results. Participants consisted of 2 groups: healthy volunteers who were not suspected of having adrenal insufficiency and patients being tested for adrenal insufficiency as part of their standard of care who were subsequently shown to have normal adrenal function on the basis of a peak cortisol value of at least 20 μg/dL. A high-dose corticotropin stimulation test was performed in all participants. Baseline, peak, and delta steroid concentrations were documented after corticotropin injection. Steroid concentrations were measured by tandem mass spectrometry. Multivariate analyses adjusted for patient age, sex, and baseline steroid concentrations.

RESULTS

With progression through the day for the time of testing, the baseline cortisol concentration decreased, while the peak and delta cortisol concentration increased (P values: <.001, .007, .007, respectively). For 11-deoxycortisol, the baseline decreased, while peak and delta values increased with later testing (P values: .017, .012, .02, respectively). Peak aldosterone concentrations increased according to their baseline values (P<.001), but were unaffected by time. Peak and delta dehydroepiandrosterone concentrations increased with time (P = .015 and .021, respectively). Referring to the various criteria for adequate steroid responses to corticotropin available in the literature, the time-related differences in this small group of patients were insufficient to draw different conclusions about results of testing.

CONCLUSIONS

Cortisol, 11-deoxycortisol, and dehydroepiandrosterone values were most influenced by testing times. In patients with borderline adrenal function who are tested at different times of the day, the modest differences we observed may be sufficient to affect conclusions about whether adrenal insufficiency is present.

Biochemical diagnosis of adrenal insufficiency: the added value of dehydroepiandrosterone sulfate measurements

OBJECTIVE

To review biochemical tests used in establishing the challenging diagnosis of adrenal insufficiency.

METHODS

We reviewed the relevant literature, including our own data, on various biochemical tests used to determine adrenal function. The advantages and limitations of each approach are discussed.

RESULTS

Baseline measurements of serum cortisol are helpful only when they are very low (≤ 5 μg/dL) or clearly elevated, whereas baseline plasma adrenocorticotropic hormone levels are helpful only when primary adrenal insufficiency is suspected. Measurements of baseline serum dehydroepiandrosterone sulfate (DHEA-S) levels are valuable in patients suspected of having adrenal insufficiency. Although serum DHEA-S levels are low in patients with primary or central adrenal insufficiency, a low level of this steroid is not sufficient by itself for establishing the diagnosis. A normal age- and sex-adjusted serum DHEA-S level, however, practically rules out the diagnosis of adrenal insufficiency. Many patients require dynamic biochemical studies, such as the 1-μg cosyntropin test, to assess adrenal function.

CONCLUSION

In establishing the diagnosis of central adrenal insufficiency, we recommend measurements of baseline serum cortisol and DHEA-S levels. In addition to these, determination of plasma levels of aldosterone, adrenocorticotropic hormone, and renin activity is necessary when primary adrenal insufficiency is suspected. With a random serum cortisol level of ≥ 12 μg/dL in the ambulatory setting or a normal age- and sex-adjusted DHEA-S level (or both), the diagnosis of adrenal insufficiency is extremely unlikely. When serum DHEA-S levels are low or equivocal, however, dynamic testing will be necessary to determine hypothalamic-pituitary-adrenal axis function.

Adrenocortical function in young adults with diabetes mellitus type 1

In 75 young adults with diabetes mellitus type 1 (DM 1) we have performed a cross-sectional study to gain more information about their adrenocortical function. We have found in a surprisingly large portion of patients (25%) a subnormal response (<500 nmol/L, low responders) of the serum cortisol during low-dose Synacthen test, accompanied by significantly decreased stimulated values of aldosterone and salivary cortisol. Basal serum cortisol, aldosterone, and dehydroepiandrosterone sulphate (in women only) were significantly reduced in low responders as well, while ACTH, cortisol binding globulin, plasma renin activity, urinary free cortisol/24h, and salivary cortisol did not differ. The results indicate that the disorder of adrenocortical function in low responders occurs in all adrenocortical zones. The patients with the highest risk in respect to revealed hypocorticalism were DM 1 with autoimmune thyroiditis, 13 out of 36 in contrast to 5 out of 39 suffered from isolated form of DM 1, with onset around 30 years, independently on sex. The biorhythm of salivary cortisol in low responders under real-life conditions did not significantly differ from normal responders, except of the decreased values in the morning. Antibodies against 21-hydroxylase and adrenal cortex were negative in the entire group of diabetics studied. In conclusion, this is the first study to demonstrate in as much as 25% of young adults with DM 1 patients without any signs of adrenal autoimmunity decreased both basal and stimulated serum cortisol and aldosterone levels, implying existence of subclinical primary hypocorticalism.

Association of genetic polymorphisms and autoimmune Addison's disease

Autoimmune Addison's disease (AAD) is a complex genetic disease that results from the interaction of a predisposing genetic background with as yet unknown environmental factors. The disease is marked by the appearance of circulating autoantibodies against steroid 21-hydroxylase. Mutations of the autoimmune regulator gene are responsible for the so-called autoimmune polyendocrine syndrome type I (APS I), of which AAD is a major disease component. Among genetic factors for isolated AAD and APS II, a major role is played by HLA class II genes: HLA-DRB1 0301-DQA1 0501-DQB1 0201 and DRB1 04-DQA1 0301-DQB1 0302 are positively, and RB1 0403 is negatively, associated with a genetic risk for AAD. The MHC class I chain-related gene A allele 5.1 is strongly and positively associated with AAD. Other gene polymorphisms contributing to genetic risk for AAD are MHC2TA, the gene coding for class II transactivator, the master regulator of class II expression, cytotoxic T lymphocyte antigen-4, PTPN22 and the vitamin D receptor.

Recent advances in adrenal autoimmunity

Autoimmune Addison's disease (AAD) results from the immune-mediated destruction of adrenocortical cells. AAD is a major component of the autoimmune polyendocrine syndromes type 1 (APS 1) and type 2. The adrenal autoimmune process is made evident by the apperance of circulating autoantibodies against the steroidogenic enzyme 21-hydroxylase. Detection of 21-hydroxylase in patients with endocrine autoimmune diseases enables the identification of subjects with preclinical AAD. An impaired response to a corticotrophin stimulation test marks the irreversible stage of preclinical AAD and predicts progression towards clinical AAD in over 80% of cases. APS 1 is caused by mutations of the autoimmune regulator (AIRE) gene, which encodes an activator of transcription, Aire, that induces the expression of autoantigens in thymic medullary epithelial cells and promotes immunological tolerance. Isolated and APS 2-related AAD is an autoimmune disease with evidence for complex genetic susceptibility caused by T-cell-mediated destruction of adrenocortical cells, with a major contribution of HLA genes. The target cells in the adrenal cortex participate in the immune reaction by releasing chemokines, such as CXCL-10, that attract Th1 cells.

Plasma aldosterone response to the low-dose adrenocorticotrophin (ACTH 1-24) stimulation test

BACKGROUND

Endocrine tests for adrenal insufficiency use pharmacological doses of stimulant such as ACTH. More physiological tests have often used high-dose protocols for sampling frequency.

AIMS

To evaluate the response of plasma aldosterone concentration to low doses (125, 250 and 500 ng/m(2) body surface area) of synthetic ACTH.

DESIGN

A randomised trial in six normal adult males aged 18-27 years.

MATERIALS AND METHODS

Aldosterone concentration was measured by radioimmunoassay in serum from blood samples taken at 10 min intervals for 90 min.

RESULTS

All three doses produced a significant rise in plasma aldosterone concentration (125 ng/m(2), P = 0.003; 250 ng/m(2), P < 0.001; 500 ng/m(2), P < 0.001) but there was no effect of dose on either the peak or incremental plasma aldosterone concentration. Mean time to peak was similar between the doses and the two higher doses were associated with a longer secretory profile (125 ng/m(2) 56 (26 SD) mins, 250 ng/m(2) 74 (19) mins, 500 ng/m(2) 77 (21) mins; F = 3.39; P = 0.04). Peaks of 100% were detected within 30 min of drug administration and peak response was associated with the prestimulation plasma aldosterone concentration (r = 0.45; P = 0.003). The between- and within-individual coefficients of variation for prestimulation concentrations were 37.0% and 32.8%, and for the peak response were 27.2% and 27.2%, respectively.

CONCLUSIONS

The response of plasma aldosterone concentrations to low-dose ACTH administration requires a blood sampling protocol of 0, 10, 20 and 30 min to capture concentrations near the peak response. The high-dose protocol would have missed the response. Over the dose range studied no dose-response was observed so the selection of dose should be based on the dose effective to release steroids in the glucocorticoid pathway if this study is to be used in conjunction with such evaluation.

Assessment of adrenal function by measurement of salivary steroids in response to corticotrophin in patients infected with human immunodeficiency virus

OBJECTIVE

Adrenal insufficiency has been reported among critically ill HIV-infected patients. This is the first study that attempts to detect subclinical hypoadrenal states in non-critical HIV patients through salivary steroids in response to intramuscular low-dose ACTH injection.

PATIENTS AND METHODS

We studied 21 ambulatory adult HIV-infected patients without specific clinical signs or symptoms of adrenal insufficiency. Normal salivary flow-rate and salivary alpha-amylase activity confirmed adequate salivary gland function. Salivary cortisol (SAF) and salivary aldosterone (SAL) were obtained at baseline and 30 min after the injection of 25 microg of ACTH in the deltoid muscle (LDT(s)). Assessment of salivary steroids after stimulation with 250 microg of intramuscular ACTH (HDT(s)) was performed on those who hyporesponded to LDT(s). Basal blood samples were drawn for steroids, renin and ACTH measurements.

RESULTS

At baseline SAF and SAL correlated significantly (p=0.0001) with basal serum cortisol and aldosterone (r=0.70 and 0.91, respectively). Plasma ACTH and renin concentrations were within the normal range in all patients. Eight of the twenty-one HIV(+) patients were LDT(s) hyporesponders in either SAF (n:1) or SAL (n:7). LDT(s) repeated in six cases after a year reconfirmed the impairment of aldosterone secretion. LDT(s) hyporesponders had normal steroid responses to HDT(s).

CONCLUSIONS

LDT(s) is a simple, safe, well-accepted and non-invasive approach to assess adrenal function in HIV-infected ambulatory patients. It revealed subnormal cortisol (5%) and aldosterone responses (33%) when HDT(s) results were normal.

Use of steroid profiles in determining the cause of adrenal insufficiency

HYPOTHESIS

A cortisol response to adrenocorticotropin injection is the standard test for diagnosing adrenal insufficiency. Multiple steroid hormones can now be accurately measured by tandem mass spectrometry in a single sample. The study objective was to determine whether a steroid profile, created by simultaneous measurement of 10 steroid hormones by tandem mass spectrometry, would help determine the cause of adrenal insufficiency.

DESIGN

A 10-steroid profile was measured by tandem mass spectrometry during the performance of a standard high dose cortrosyn stimulation test. The steroids were measured at baseline, 30, and 60min following synthetic adrenocorticotropin injection. Adrenal insufficiency was defined as a peak cortisol level of less than 20microg/dL. Testing was conducted in the general clinical research center of a university medical center. Normal volunteers, patients suspected of having adrenal insufficiency, and patients with known adrenal insufficiency participated.

RESULTS

Our results showed that adrenal insufficiency of any cause was adequately diagnosed using the response of 11-deoxycortisol, dehydroepiandrosterone, or these analytes combined in a two-steroid profile. A three-steroid profile yielded a test with 100% accuracy for discriminating primary adrenal insufficiency from normal status. Primary adrenal insufficiency was well separated from secondary adrenal insufficiency using only a single aldosterone value. 11-Deoxycortisol, dehydroepiandrosterone, and a two-steroid profile each provided fair discrimination between secondary adrenal insufficiency and normal status.

CONCLUSIONS

We conclude that stimulated levels of aldosterone, 11-deoxycortisol, dehydroepiandrosterone, and a two- or three-steroid profile provided additional discrimination between states of adrenal sufficiency and insufficiency. It is proposed that a steroid profile measuring cortisol, aldosterone, 11-deoxycortisol, and dehydroepiandrosterone would potentially improve the ability to determine the cause of adrenal insufficiency.

Relationship between Cortisol Increment and Basal Cortisol: Implications for the Low-Dose Short Adrenocorticotropic Hormone Stimulation Test

Background: We analyzed the low-dose (1 μg) rapid adrenocorticotropic hormone test (LDST) in 17 patients with a normal hypothalamic-pituitary-adrenal axis to determine reference intervals for the LDST on the basis of poststimulation cortisol increments.

Methods: We analyzed test results for 17 patients (14 females and 3 males; age range, 18–46 years) who had received a 2-mL aliquot of low-dose (1 μg) adrenocorticotropic hormone prepared from one 250-μg vial of Synacthen diluted in 500 mL of sterile normal saline solution. Sampling took place at 0, 20, 30, and 60 min post stimulation. The cortisol increment was plotted against basal cortisol.

Results: We observed a marked interdependence of the basal cortisol concentration with the increase in cortisol concentration. The relationship was inverse and linear with the best fit observed at 30 min post stimulation. The lower 95% prediction limit for basal cortisol at the zero increment was 400 nmol/L with a mean concentration of 600 nmol/L.

Conclusions: We propose that a peak cortisol concentration &lt;400 nmol/L is a sufficient single criterion for abnormal adrenal function as assessed by the LDST. Concentrations of 400–600 nmol/L are in the gray area, and those &gt;600 nmol/L confirm normal adrenal function. Repeat analyses with larger sample sizes are warranted to confirm these observations.

A new less-invasive and more informative low-dose ACTH test: salivary steroids in response to intramuscular corticotrophin

OBJECTIVE

The intravenous low-dose ACTH test has been proposed as a sensitive tool to assess adrenal function through circulating steroids. The aims of this study were to: (a) find the minimal intramuscular ACTH dose that induced serum and salivary cortisol and aldosterone responses equivalent to those obtained after a pharmacological dose of ACTH; and (b) define the minimum normal salivary cortisol and aldosterone responses in healthy subjects to that dose of ACTH. We also compared the performances of the standard- and low-dose ACTH intramuscular tests to screen patients with known hypothalamo-pituitary-adrenal impairments.

DESIGN

Rapid ACTH tests were performed in individuals using various intramuscular doses (12.5, 25 and 250 microg) at 2-week intervals.

SUBJECTS

Twenty-one healthy volunteers and 19 patients with primary (nine cases) and secondary (10 cases) adrenal insufficiency.

MEASUREMENT

Serum and salivary cortisol and aldosterone concentrations were measured at baseline and after ACTH. Serum cortisol > or = 552.0 nmol/l and aldosterone > or = 555.0 pmol/l concentrations at 30 min after 250 microg of ACTH were defined as normal responses.

RESULTS

In healthy volunteers cortisol and aldosterone responded to ACTH in a dose-dependent manner. The time to peak in saliva for each steroid was delayed as the dose of ACTH increased. The minimum ACTH dose that produced equivalent steroid responses at 30 min to 250 microg of ACTH (standard-dose test; SDT) was 25 microg (low-dose test; LDT). Saliva collection 30 min after LDT and SDT showed cortisol and aldosterone concentrations of at least 20.0 nmol/l and 100.0 pmol/l, respectively. These values were defined as normal steroid responses. Blunted salivary steroid responses to LDT and SDT were found in all patients with primary adrenal insufficiency. Subnormal salivary cortisol levels in response to LDT and SDT were found in all patients with secondary adrenal insufficiency. In five patients full recovery of adrenal function was demonstrated by both tests after steroid withdrawal. In the follow-up of four patients studied during the recovery period, subnormal SAF response after LDT and normal after SDT was demonstrated. Preservation of the adrenal glomerulosa was found in all the patients with secondary adrenal insufficiency through the normal rise in salivary aldosterone after both LDT and SDT.

CONCLUSIONS

Adrenal function can be accurately investigated with simultaneous measurements of salivary cortisol and aldosterone in response to 25 microg of corticotrophin injected into the deltoid muscle. Our data suggest that this may become a useful and relatively noninvasive clinical tool to detect subclinical hypoadrenal states.

Adrenal sensitivity to adrenocorticotropin 1-24 is reduced in patients with autoimmune polyglandular syndrome

Autoimmune polyglandular syndromes are fairly common diseases that are classified into four constellations based on the clinical clustering of the various component diseases. In types 1, 2, and 4, primary adrenal insufficiency due to an autoimmune process is usually present, but its diagnosis is often delayed because it is difficult to detect in a subclinical phase. It is widely accepted that the classical dose of 250 microg ACTH(1-24) is supramaximal, whereas 0.06 microg has been shown to be one of the lowest ACTH doses that is able to stimulate adrenal secretion in normal young subjects. The aim of this study was to clarify the sensitivity and maximal secretory response of the adrenal gland to ACTH in a group of patients with at least two autoimmune diseases, without clinical signs and symptoms of overt or subclinical hypocortisolism. Cortisol (F), aldosterone (A), and dehydroepiandrosterone (DHEA) responses to the sequential administration of very low and supramaximal ACTH(1-24) doses [0.06 microg followed by 250 microg ACTH(1-24) i.v. at 0 and +60 min] were studied in 18 patients with at least two autoimmune diseases (AP; age, 20-40 yr; body mass index, 22-26 kg/m(2)). The results in the patients were compared with the results recorded in 12 normal age-matched control subjects (CS; age, 22-34 yr; body mass index, 20-25 kg/m(2)). At baseline, ACTH levels in AP were within the normal range but higher (P < 0.05) than in CS, whereas F, A, DHEA, urinary-free F, and plasma renin activity were similar in both groups. F, A, and DHEA responses to ACTH were dose dependent in both groups. However, in AP, F, A, and DHEA levels showed no response to the 0.06- micro g ACTH dose, which, in turn, elicited clear responses (P < 0.01) in CS. On the other hand, F, A, and DHEA responses to 250 microg ACTH in AP were not different from those in CS. In conclusion, patients with autoimmune diseases who displayed a normal basal adrenal function showed a loss of F, A, and DHEA response to the very low ACTH dose, although they were normal responders to the high ACTH dose. These data are likely to indicate that a reduced sensitivity to ACTH in all adrenal zones occurs in patients with different types of autoimmune disease.