Hypothalamic-Pituitary Autoimmunity and Related Impairment of Hormone Secretions in Chronic Fatigue Syndrome

CONTEXT

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severe chronic illness that reduces the quality of life. A potential role of neuroendocrine autoimmune dysfunction has been hypothesized.

OBJECTIVE

This work aims to investigate the occurrence of antipituitary (APA) and antihypothalamic (AHA) antibodies and possible related hypothalamic/pituitary dysfunctions in ME/CSF patients.

METHODS

This is a case-control study conducted in a university hospital setting (Stanford, California, USA; and Naples, Italy). Thirty women with ME/CSF (group 1) diagnosed according to Fukuda, Canadian, and Institute of Medicine criteria, at Stanford University, were enrolled and compared with 25 age-matched healthy controls. APA and AHA were detected by immunofluorescence; moreover, we investigated hormonal secretions of anterior pituitary and respective target glands. APA and AHA titers both were assessed and the prevalence of pituitary hormone deficiencies was also investigated.

RESULTS

Patients in group 1 showed a high prevalence of AHA (33%) and APA (56%) and significantly lower levels of adrenocorticotropin (ACTH)/cortisol, and growth hormone (GH) peak/insulin-like growth factor-1 (IGF-1) vs controls (all AHA/APA negative). Patients in group 1A (13 patients positive at high titers, ≥ 1:32) showed ACTH/cortisol and GH peak/IGF-1 levels significantly lower and more severe forms of ME/CFS with respect to patients in group 1B (7 positive at middle/low titers, 1:16-1:8) and 1C (10 antibody-negative patients).

CONCLUSION

Both AHA and/or APA at high titers were associated with hypothalamic/pituitary dysfunction, suggesting that hypothalamic/pituitary autoimmunity may play an important role in the manifestations of ME/CFS, especially in its more severe forms.

Elevated blood pressure in high-fat diet-exposed low birthweight rat offspring is most likely caused by elevated glucocorticoid levels due to abnormal pituitary negative feedback

Being delivered as a low birthweight (LBW) infant is a risk factor for elevated blood pressure and future problems with cardiovascular and cerebellar diseases. Although premature babies are reported to have low numbers of nephrons, some unclear questions remain about the mechanisms underlying elevated blood pressure in full-term LBW infants. We previously reported that glucocorticoids increased miR-449a expression, and increased miR-449a expression suppressed Crhr1 expression and caused negative glucocorticoid feedback. Therefore, we conducted this study to clarify the involvement of pituitary miR-449a in the increase in blood pressure caused by higher glucocorticoids in LBW rats. We generated a fetal low-carbohydrate and calorie-restricted model rat (60% of standard chow), and some individuals showed postnatal growth failure caused by growth hormone receptor expression. Using this model, we examined how a high-fat diet (lard-based 45kcal% fat)-induced mismatch between prenatal and postnatal environments could elevate blood pressure after growth. Although LBW rats fed standard chow had slightly higher blood pressure than control rats, their blood pressure was significantly higher than controls when exposed to a high-fat diet. Observation of glomeruli subjected to periodic acid methenamine silver (PAM) staining showed no difference in number or size. Aortic and cardiac angiotensin II receptor expression was altered with compensatory responses. Blood aldosterone levels were not different between control and LBW rats, but blood corticosterone levels were significantly higher in the latter with high-fat diet exposure. Administration of metyrapone, a steroid synthesis inhibitor, reduced blood pressure to levels comparable to controls. We showed that high-fat diet exposure causes impairment of the pituitary glucocorticoid negative feedback via miR-449a. These results clarify that LBW rats have increased blood pressure due to high glucocorticoid levels when they are exposed to a high-fat diet. These findings suggest a new therapeutic target for hypertension of LBW individuals.

Antibodies Against Hypothalamus and Pituitary Gland in Childhood-Onset Brain Tumors and Pituitary Dysfunction

Purpose: To detect the presence of antipituitary (APA) and antihypothalamus antibodies (AHA) in subjects treated for brain cancers, and to evaluate their potential association with pituitary dysfunction. Methods: We evaluated 63 patients with craniopharyngioma, glioma, and germinoma treated with surgery and/or radiotherapy and/or chemotherapy at a median age of 13 years. Forty-one had multiple pituitary hormone deficiencies (MPHD), six had a single pituitary defect. GH was the most common defect (65.1%), followed by AVP (61.9%), TSH (57.1%), ACTH (49.2%), and gonadotropin (38.1%). APA and AHA were evaluated by simple indirect immunofluorescence method indirect immunofluorescence in patients and in 50 healthy controls. Results: Circulating APA and/or AHA were found in 31 subjects (49.2%) and in none of the healthy controls. In particular, 25 subjects out of 31 were APA (80.6%), 26 were AHA (83.90%), and 20 were both APA and AHA (64.5%). Nine patients APA and/or AHA have craniopharyngioma (29%), seven (22.6%) have glioma, and 15 (48.4%) have germinoma. Patients with craniopharyngioma were positive for at least one antibody in 39.1% compared to 33.3% of patients with glioma and to 78.9% of those with germinoma with an analogous distribution for APA and AHA between the three tumors. The presence of APA or AHA and of both APA and AHA was significantly increased in patients with germinoma. The presence of APA (P = 0.001) and their titers (P = 0.001) was significantly associated with the type of tumor in the following order: germinomas, craniopharyngiomas, and gliomas; an analogous distribution was observed for the presence of AHA (P = 0.002) and their titers (P = 0.012). In addition, we found a significant association between radiotherapy and APA (P = 0.03). Conclusions: Brain tumors especially germinoma are associated with the development of hypothalamic-pituitary antibodies and pituitary defects. The correct interpretation of APA/AHA antibodies is essential to avoid a misdiagnosis of an autoimmune infundibulo-neurohypophysitis or pituitary hypophysitis in patients with germinoma.

ENDOCRINOLOGY AND ADOLESCENCE: Dealing with transition in young patients with pituitary disorders

INTRODUCTION

The transition age is the period between childhood to adulthood; it refers to a broad set of physical, cognitive and sociocultural modifications, arbitrarily defined as starting in late puberty and ending with full adult maturation. Pituitary disorders in adolescence represent a challenge that requires careful management during the transition to adult care.

METHODS

Given the complexity of care of pituitary disorders in the transition age, we have reviewed the relevant medical literature focusing on aetiology, clinical manifestations, treatment strategies of GH deficiency (GHD), hypogonadotrophic hypogonadism (HH) in male and female adolescents, central hypothyroidism (CH), central adrenal insufficiency (CAI) and cranial diabetes insipidus (CDI) at this time. The objective of the present review is to provide an up-to-date evaluation of the transition period to evaluate the specific needs of adolescents with chronic pituitary disease in order to optimise their management.

RESULTS

We provide an overview of current clinical management of GHD, HH, CH, CAI and CDI in the transition age.

CONCLUSIONS

Specific changes occur in pituitary function during the transition period. A holistic approach including discussion of patients' concerns and emotional support should constitute a key component of managing pituitary disorders in adolescence. Special transition clinics where paediatric and adult endocrinologists work together, should be increasingly created and strengthened to bridge care, to promote continuity and adherence to treatment and to limit potential negative development, metabolic, skeletal and cardiovascular sequelae of discontinuity of care among adolescents with pituitary disorders.

Pituitary involvement in patients with granulomatosis with polyangiitis: case series and literature review

GPA with pituitary involvement is a rare condition which is prone to be misdiagnosed. The aim of this study was to summarize clinical features of pituitary involvement in GPA and facilitate early diagnosis. Twelve GPA patients were retrospectively analyzed at a single hospital between 2000 and 2017. A literature review was conducted to compare previous findings with our clinical results. The incidence rate of pituitary involvement in GPA was 3.9% (12/304) without sexual predilection. Other impairments included ear, nose and throat (n = 12), oculi (n = 10), lung (n = 6), meninges (n = 4), kidney (n = 3), and skin (n = 2). Antineutrophil cytoplasmic antibodies (ANCA) were positive in all patients with lung or kidney involvement (n = 6/6), while ANCA were negative in almost all patients without lung or kidney involvement (n = 5/6). Endocrine abnormalities included central diabetes insipidus (CDI, n = 11/12) hypogonadotropic hypogonadism (n = 6/11), adrenocorticotropic hormone deficiency (n = 4/7), thyroid-stimulating hormone deficiency (n = 5/11), and growth hormone deficiency (n = 3/9). Enlarged pituitary gland (n = 6), absence of posterior hyperintense signal on T1-weighed images (n = 11) and hypertrophic cranial pachymeningitis (n = 4) were common radiological manifestations. After treatment, nine patients experienced remission but one died. Pituitary images of 3/4 patients showed size of pituitary lesions decreased. CDI was not alleviated and hypopituitarism remained in two patients. Pituitary involvement in GPA can occur at any time throughout the course of disease, including at the initial presentation. GPA could not be excluded based on negative-ANCA in patients with pituitary abnormality alone. CDI and hypogonadotropic hypogonadism are dominant endocrine abnormalities. Systemic diseases may alleviate and pituitary images may improve after treatment, though the recovery of pituitary function is rare.

Levothyroxine absorption test results in patients with TSH elevation resistant to treatment

INTRODUCTION

Persistent elevation of thyroid-stimulating hormone (TSH) is common in endocrinology practice in patients undergoing replacement or suppression therapy with levothyroxine sodium (LT4). After examining the causes of this condition, LT4 absorption test is recommended. In this report, we wanted to share our results of LT4 absorption test in patients with elevated TSH levels.

MATERIALS-METHODS

The files of patients who presented to our clinic between 2015 and 2018, whose TSH elevation continued despite high-dose LT4 therapy, and who underwent absorption test were reviewed retrospectively.

RESULTS

Levothyroxine sodium absorption test was applied to five patients. Absorption test revealed LT4 malabsorption in two patients and pseudomalabsorption in the other three patients.

DISCUSSION

When all published pseudomalabsorption cases were considered, it has been stated that at least 2.5 times increase in basal fT4 level may exclude malabsorption. The formula we used has been implemented by Cleveland Clinic since 2014.

CONCLUSION

In cases where TSH normalization is not achieved despite high doses of LT4 therapy, LT4 absorption test is an easy test for administration and interpretation and prevents unnecessary medical treatments and examinations.

Can the positive association of osteocalcin with testosterone be unmasked when the preeminent hypothalamic-pituitary regulation of testosterone production is impaired? The model of spinal cord injury

PURPOSE

Osteocalcin (OCN), released from the bone matrix during the resorption phase, in its undercarboxylated form, stimulates testosterone (T) biosynthesis in mouse and a loss-of-function mutation of its receptor was associated with hypergonadotropic hypogonadism in humans. Nevertheless, when population-based studies have explored the OCN-T association, conflicting results have been reported. Hypothesizing that the evidence of a positive association between OCN and T could have been hindered by the preeminent role of a well-functioning hypothalamus-pituitary axis in promoting T biosynthesis, we explored this association in men with chronic spinal cord injury (SCI), exhibiting high prevalence of non-hypergonadotropic androgen deficiency.

METHODS

Fifty-five consecutive men with chronic SCI underwent clinical/biochemical evaluations, including measurements of total T (TT), OCN and 25(OH)D levels. Free T (FT) levels were calculated by the Vermeulen formula. Comorbidity was scored by Charlson comorbidity index (CCI).

RESULTS

A biochemical androgen deficiency (TT < 300 ng/dL) was observed in 15 patients (27.3%). TT was positively correlated with OCN, 25(OH)D and leisure time physical activity and negatively correlated with age, BMI and CCI. OCN was also positively correlated with calculated FT and negatively correlated with BMI and HOMA-IR. At the multiple linear regression analyses, a positive association of OCN with TT and calculated FT persisted after adjustment for confounders.

CONCLUSIONS

The positive association here found between OCN and T levels in men with chronic SCI reinforces the notion that a bone-testis axis is also functioning in humans and suggests that it can be unmasked when the preeminent hypothalamic-pituitary regulation of T production is impaired.

Effects of bimagrumab, an activin receptor type II inhibitor, on pituitary neurohormonal axes

BACKGROUND

Bimagrumab is a human monoclonal antibody inhibitor of activin type II receptors (ActRII), with anabolic action on skeletal muscle mass by blocking binding of myostatin and other negative regulators of muscle growth. Bimagrumab is under evaluation for muscle wasting and associated functional loss in hip fracture and sarcopenia, and in obesity. Bimagrumab also blocks other endogenous ActRII ligands, such as activins, which act on the neurohormonal axes, pituitary, gonads and adrenal glands.

AIM

To evaluate the effect of bimagrumab on the pituitary-gonadal and pituitary-adrenal axes in humans.

METHODS

Healthy men and women, aged 55 to 75 years, received bimagrumab intravenously 10 mg/kg or placebo on Day 1 and Day 29. Pituitary-gonadal and pituitary-adrenal functions were evaluated with basal hormone measurement and standard gonadotropin-releasing hormone (GnRH) and adrenocorticotropic hormone (ACTH) stimulation tests at baseline, Week 8 and at the end of study (EOS)-Week 20.

RESULTS

At Week 8, follicle-stimulating hormone (FSH) levels were reduced by 42.16 IU/L (P < .001) and luteinizing hormone (LH) levels were increased by 2.5 IU/L (P = .08) over placebo in response to bimagrumab in women but not in men. Effects that were reversible after bimagrumab was cleared. Gonadal and adrenal androgen levels were not affected by exposure to bimagrumab.

CONCLUSION

Bimagrumab alters the function of pituitary gonadotroph cells, consistent with blockade of activin on local ActRII. This effect is reversible with clearance of bimagrumab. Bimagrumab did not impact gonadal and adrenal androgen secretion.

Discordance between mass spectrometry and immunometric IGF-1 assay in pituitary disease: a prospective study

PURPOSE

Measuring IGF-1, a biomarker for GH activity, is critical to evaluating disordered hypothalamic-pituitary GH axis. Inconsistent IGF-1 measurements among different immunoassays are well documented. We switched from Immulite 2000 immunoassay to narrow-mass-extraction, high-resolution liquid chromatography mass-spectrometry (LC-MS) compliant with recent consensus recommendations on assay standardization. Comparability of these two assays in patients with pituitary disease in a clinical practice setting is not known. We sought to compare IGF-1 levels on Immulite 2000 and LC-MS in samples from naïve and treated patients with secretory and non-secretory pituitary masses.

METHODS

We prospectively collected serum samples from 101 patients treated at the Cedars-Sinai Pituitary Center between February 2012 and March 2014. We intentionally recruited more patients with acromegaly or GH deficiency to ensure a clinically representative cohort. Samples were classified as in or out of the respective reference ranges. Bland-Altman analysis was used to assess agreement between assays.

RESULTS

Twenty-four percent of samples were classified differently as below, in, or above range. Agreement between the assays was poor overall, with a significant bias for immunoassay reporting higher values than LC-MS. This pattern was also observed in patients with acromegaly and those with ≥ 2 pituitary hormone deficiencies.

CONCLUSIONS

IGF-1 results may differ after switching from an older immunoassay to a consensus-compliant assay such as LC-MS. Clinicians should consider the potential impact of assay switching before altering treatment due to discrepant results, particularly in patients monitored over time, such as those with acromegaly and GH deficiency.

Copeptin as a marker of an altered CRH axis in pituitary disease

BACKGROUND

Copeptin (pre-proAVP) secreted in equimolar amounts with vasopressin closely reflects vasopressin release. Copeptin has been shown to subtly mirror stress potentially mediated via corticotrophin-releasing hormone. To further test a potential direct interaction of corticotrophin-releasing hormone with copeptin release, which could augment vasopressin effects on pituitary function, we investigated copeptin response to corticotrophin-releasing hormone.

PATIENTS AND METHODS

Cortisol, adrenocorticotropin and copeptin were measured in 18 healthy controls and 29 subjects with a history of pituitary disease during standard corticotrophin-releasing hormone test.

RESULTS

Patients with previous pituitary disease were subdivided in a group passing the test (P1, n = 20) and failing (P2, n = 9). The overall copeptin response was higher in controls than in subjects with pituitary disease (area under the curve, p = 0.04 for P1 + P2) with a maximum increase in controls from 3.84 ± 2.86 to 12.65 ± 24.87 pmol/L at 30 min, p < 0.05. In contrast, both groups of pituitary patients lacked a significant copeptin response to corticotrophin-releasing hormone, and even in P1, where adrenocorticotropin concentrations increased fourfold (mean, 21.48 vs. 91.53 pg/mL, p < 0.01), copeptin did not respond (e.g., 4.35 ± 5.81 vs. 5.36 ± 6.79 pmol/L, at 30 min, p = ns).

CONCLUSIONS

Corticotrophin-releasing hormone is able to stimulate copeptin release in healthy controls suggesting a direct interaction of corticotrophin-releasing hormone and vasopressin/vasopressin. Interestingly, this relation is altered already in the group of pituitary patients who pass the standard corticotrophin-releasing hormone test indicating (1) the corticotrophin-releasing hormone-adrenocorticotropin-cortisol response is largely independent from the vasopressin system, but (2) the corticotrophin-releasing hormone-vasopressin interaction reflected by copeptin may be much more sensitive to reveal subtle alterations in the regulation of pituitary function.

Perioperative hypothalamic pituitary adrenal function in patients with silent corticotroph adenomas

BACKGROUND

Silent corticotroph adenomas (SCAs) are characterized by strong ACTH immunostaining without clinical manifestations of hypercortisolism. Patients with SCAs often present with mechanical symptoms related to tumor growth. This study investigates the hypothalamic pituitary adrenal axis (HPA) characteristics after adenomectomy in patients with SCAs.

METHODS

Biochemical parameters of HPA function were monitored frequently after surgical resection of non-functioning macroadenomas. Levels of ACTH, cortisol, DHEA and DHEA-S were measured frequently for 48 h after adenomectomy. HPA data of patients with SCAs (n = 38) were compared to others (Controls) with non-secreting, ACTH-negative immunostaining adenomas of similar age and gender distribution (n = 182) who had adenomectomy.

RESULT

Plasma ACTH increased (P < 0.0001) equally in patients with SCA and controls reaching a peak at 3 h (238 ± 123 vs. 233 ± 96 ng/L, respectively) after extubation declining thereafter to baseline values 24-36 h. Similarly, serum cortisol levels increased (P < 0.0001) equally in both groups reaching a maximum at 7 h (36.8 ± 13.9 vs. 39.3 ± 13.3 ug/dL). Serum DHEA also increased (P < 0.001) equally in both groups in parallel to the rise in serum cortisol. Serum DHEA-S levels similarly increased (P < 0.001) from their respective baseline (105.9 ± 67.5 and 106.5 ± 58.7 ug/dL) reaching their peak (154.5 ± 69.5 and 153.5 ± 68.6 ug/dL; respectively) at 15 h after extubation. None of the patients acquired any hormone deficits.

CONCLUSIONS

Under the maximal stimulation of the peri-operative stress, HPA function in patients with SCA behaved in an identical manner to others with ACTH-negative macroadenomas. Thus, despite the strong ACTH-positive immunostaining of these tumors, SCAs are truly non- functional.

Dynamic GnRH and hCG testing: establishment of new diagnostic reference levels

OBJECTIVE

Gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) stimulation tests may be used to evaluate the pituitary and testicular capacity. Our aim was to evaluate changes in follicular-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone after GnRH and hCG stimulation in healthy men and assess the impact of six single nucleotide polymorphisms on the responses.

DESIGN

GnRH and hCG stimulation tests were performed on 77 healthy men, 18-40 years (reference group) at a specialized andrology referral center at a university hospital. The potential influence of the tests was illustrated by results from 45 patients suspected of disordered hypothalamic-pituitary-gonadal axis.

METHODS

Baseline, stimulated, relative and absolute changes in serum FSH and LH were determined by ultrasensitive TRIFMA, and testosterone was determined by LC-MS/MS.

RESULTS

For the reference group, LH and FSH increased almost 400% and 40% during GnRH testing, stimulated levels varied from 4.4 to 58.8 U/L and 0.2 to 11.8 U/L and FSH decreased in nine men. Testosterone increased approximately 110% (range: 18.7-67.6 nmol/L) during hCG testing. None of the polymorphisms had any major impact on the test results. Results from GnRH and hCG tests in patients compared with the reference group showed that the stimulated level and absolute increase in LH showed superior identification of patients compared with the relative increase, and the absolute change in testosterone was superior in identifying men with Leydig cell insufficiency, compared with the relative increase.

CONCLUSIONS

We provide novel reference ranges for GnRH and hCG test in healthy men, which allows future diagnostic evaluation of hypothalamic-pituitary-gonadal disorders in men.

Circadian variation in serum cortisol during hydrocortisone replacement is not attributable to changes in cortisol-binding globulin concentrations

BACKGROUND

Patients taking hydrocortisone (HC) replacement for primary or secondary adrenal failure require individual adjustment of their dose. In addition to modifying the administered doses of HC for each patient, physicians are increasingly interested in variations in the bioavailability of glucocorticoid replacement. One potential determinant of the bioavailability of replaced HC is a variation in serum cortisol-binding globulin (CBG) concentration, which may, in turn, affect interpretation of cortisol profiles and individual dose selection for patients on hydrocortisone replacement therapy.

AIM

To investigate the hypothesis that there is a circadian variation in CBG levels.

METHODS AND RESULTS

A total of 34 male patients divided into 3 groups (10 patients with non-somatotroph structural pituitary disease on HC replacement, 11 patients with treated acromegaly on HC replacement and 13 patients with treated acromegaly not on HC replacement) and 10 healthy volunteers were included. Cortisol and CBG levels were measured at 6 time points (0800, 1100, 1300, 1500, 1700 and 1900). No significant circadian variation in CBG concentration was found in any of the 4 groups.

CONCLUSION

Circadian variation in serum cortisol during hydrocortisone replacement is not attributable to changes in cortisol-binding globulin concentration. Changes in serum cortisol levels may thus be explained by other factors including 11 β-hydroxysteroid dehydrogenase type 1 activity or circadian changes in the binding properties of CBG.

Pituitary Stalk Interruption Syndrome from Infancy to Adulthood: Clinical, Hormonal, and Radiological Assessment According to the Initial Presentation

Background

Patients with pituitary stalk interruption syndrome (PSIS) are initially referred for hypoglycemia during the neonatal period or growth retardation during childhood. PSIS is either isolated (nonsyndromic) or associated with extra-pituitary malformations (syndromic).

Objective

To compare baseline characteristics and long-term evolution in patients with PSIS according to the initial presentation.

Study Design

Sixty-seven patients with PSIS were included. Data from subgroups were compared: neonates (n = 10) versus growth retardation patients (n = 47), and syndromic (n = 32) versus nonsyndromic patients (n = 35).

Results

Neonates displayed a more severe hormonal and radiological phenotype than children referred for growth retardation, with a higher incidence of multiple hormonal deficiencies (100% versus 34%; P = 0.0005) and a nonvisible anterior pituitary lobe (33% versus 2%; P = 0.0017). Regular follow-up of growth might have allowed earlier diagnosis in the children with growth retardation, as decreased growth velocity and growth retardation were present respectively 3 and 2 years before referral. We documented a progressive worsening of endocrine impairment throughout childhood in these patients. Presence of extra-pituitary malformations (found in 48%) was not associated with more severe hormonal and radiological characteristics. Growth under GH treatment was similar in the patient groups and did not vary according to the pituitary MRI findings.

Conclusions

PSIS diagnosed in the neonatal period has a particularly severe hormonal and radiological phenotype. The progressive worsening of endocrine impairment throughout childhood justifies periodic follow-up to check for additional hormonal deficiencies.

HLA Markers DQ8 and DR53 Are Associated With Lymphocytic Hypophysitis and May Aid in Differential Diagnosis

IMPORTANCE

Lymphocytic hypophysitis (LH) is a poorly understood autoimmune disorder of the pituitary gland. Symptoms include headache, pituitary dysfunction, visual disturbances, and neurological deficits. The diagnosis can be made based on clinical and biochemical findings, but for atypical presentations, no circulatory diagnostic biomarkers exist, and a pituitary biopsy is necessary for diagnosis.

OBJECTIVES

We used high-resolution human leukocyte antigen (HLA) screening assays to investigate a relationship between specific HLA markers and LH.

DESIGN

This was a retrospective analysis.

SETTING

The study was conducted at a tertiary referral center.

SUBJECTS

Fifteen patients with sporadic LH, 4 patients with melanoma who developed hypophysitis after administration of cytotoxic T lymphocyte antigen 4 (CTLA4) antibodies, and 1 patient with sarcoid-associated hypophysitis were evaluated.

INTERVENTION

Clinical data, including endocrine function, were assessed, and HLA typing was performed in all 20 patients with hypophysitis, 50 control patients with other sellar abnormalities, and 4 CTLA4 antibody-treated patients without hypophysitis.

RESULTS

Two major histocompatibility class II HLA markers, DQ8 and DR53, were found in 13 of 15 (87%) and 12 of 15 (80.0%) patients with sporadic LH, respectively. In contrast, none of the 4 patients who developed hypophysitis after administration of the CTLA4 antibodies exhibited the HLA-DQ8 marker and only 1 of 4 (25%) exhibited the HLA-DR53 marker. In a parallel group of 50 control subjects with sellar masses and 4 CTLA4 antibody-treated patients who did not develop evidence of pituitary failure, the candidate HLA subtypes were found in ∼20% for DQ8 and ∼48% for DR53, respectively.

CONCLUSION AND RELEVANCE

The HLA markers, DQ8 and DR53, were found to be commonly present in patients with LH. The odds ratio of a patient with LH expressing the HLA-DQ8 marker is 23.1-fold higher than that of a patient with another sellar mass. HLA-DQ8 testing may assist in diagnosis and avoid unnecessary biopsies in patients with atypical LH.

Acylated ghrelin as provocative test for the diagnosis of ACTH deficiency in patients with hypothalamus-pituitary disease

The insulin tolerance test (ITT) is the gold standard to evaluate adrenocorticotropic hormone (ACTH) insufficiency. However, alternative tests have been proposed such as metyrapone, glucagon, and ACTH stimulation test. We determined the diagnostic reliability of testing with ghrelin, the natural GH secretagogue that is a potent stimulus exploring the integrity of hypothalamic-pituitary-adrenal axis. We studied the ACTH and cortisol response to acylated ghrelin in 49 patients with history of pituitary disease. The best cortisol and ACTH cut offs to ghrelin test, defined as those with the best sensitivity (SE) and specificity (SP), were identified using the ROC analysis. We also compared accuracy of ghrelin test with that of a simple and cheap test like basal cortisol and ACTH levels. The best cortisol and ACTH cut offs to ghrelin test were ≤11.6 µg/dl (SE 86.4%, SP 77.8%) and ≤32.5 pg/ml (SE 72.7%, SP 51.9%), respectively; the best basal cortisol and ACTH cut offs were ≤10.7 µg/dl (SE 90.9%, SP 70.4%) and ≤25.0 pg/ml (SE 85%, SP 37%), respectively. The diagnostic accuracy was 81.6, 60.9, 79.6, and 57.4%, respectively. A comparison between ROC AUC showed a great diagnostic power for cortisol, both stimulated and basal, versus ACTH, both stimulated and basal, but no difference between stimulated and basal cortisol evaluation. Our data show that testing with acylated ghrelin is not a useful diagnostic tool for the diagnosis of central hypocortisolism; particularly ghrelin test adds no more information that basal cortisol evaluation in the diagnosis of ACTH deficiency in patients with hypothalamus-pituitary disease.

Low immediate postoperative serum-cortisol nadir predicts the short-term, but not long-term, remission after pituitary surgery for Cushing's disease

BACKGROUND

Cushing's disease is an ACTH-producing pituitary adenoma, and the primary treatment is microscopic or endoscopic transsphenoidal selective adenectomy. The aims of the present study were to evaluate whether the early postoperative S-cortisol level can serve as a prognostic marker for short- and long-term remission, and retrospectively review our own short and long term results after surgery for Cushing's disease.

METHODS

This single centre, retrospective study consists of 19 consecutive patients with Cushing's disease who underwent transsphenoidal surgery. S-cortisol was measured every 6 h after the operation without any glucocorticoid replacement. We have follow-up on all patients, with a mean follow-up of 68 months.

RESULTS

At the three-month follow-up, 16 patients (84 %) were in remission; at 12 months, 18 (95 %) were in remission and at the final follow-up (mean 68 months), 13 (68 %) were in remission. Five-years recurrence rate was 26 %. The mean postoperative S-cortisol nadir was significantly lower in the group of patients in remission than in the non-remission group at 3 months, but there was no difference between those in long-term remission compared to those in long-term non-remission. The optimal cut-off value for classifying 3-month remission was 74 nmol/l.

CONCLUSION

We achieved a 95 % 1-year remission rate with transsphenoidal surgery for Cushing's disease in this series of consecutive patients. However, the 5-year recurrence rate was 26 %, showing the need for regular clinical and biochemical controls in this patient group. The mean postoperative serum-cortisol nadir was significantly lower in patients in remission at 3 months compared to patients not in remission at 3 months, but a low postoperative S-cortisol did not predict long-term remission.

Relationship between pituitary stalk (PS) visibility and the severity of hormone deficiencies: PS interruption syndrome revisited

CONTEXT

Pituitary stalk interruption syndrome (PSIS) is a rare cause of combined pituitary hormone deficiency characterized by a triad shown in pituitary imaging, yet it has never been evaluated due to the visibility of pituitary stalk (PS) in imaging findings.

OBJECTIVE

The major objective of the study was to systematically describe the disease including clinical presentations, imaging findings and to estimate the severity of anterior pituitary hormone deficiency based on the visibility of the PS.

METHODS

This was a retrospective study including 74 adult patients with PSIS in Shanghai Clinical Center for Endocrine and Metabolic Diseases between January 2010 and June 2014. Sixty had invisible PS according to the findings on MRI, while the rest had a thin or intersected PS. Basic characteristics and hormonal status were compared.

RESULTS

Of the 74 patients with PSIS, age at diagnosis was 25 (22-28) years. Absent pubertal development (97·3%) was the most common presenting symptom, followed by short stature. Insulin tolerance test (ITT) and gonadotrophin-releasing hormone (GnRH) stimulation test were used to evaluate the function of anterior pituitary. The prevalence of isolated deficiency in growth hormone (GH), gonadotrophins, corticotrophin and thyrotrophin were 100%, 97·2%, 88·2% and 70·3%, respectively. Although the ratio of each deficiency did not vary between patients with invisible PS and with visible PS, panhypopituitarism occurred significantly more frequent in patients with invisible PS. Patients with invisible PS had significantly lower levels of luteinizing hormone (LH), follicle stimulation hormone (FSH) and hormones from targeted glands including morning cortisol, 24-h urine free cortisol, free triiodothyronine (FT3), free thyroxine (FT4) and testosterone (T) in male than patients with visible PS. Moreover, patients with invisible PS had lower peak LH and FSH in GnRH stimulation test, and higher peak cortisol in ITT while peak GH remained unchanged between two groups.

CONCLUSIONS

The prevalence of multiple anterior pituitary hormone deficiency was high in adult patients with PSIS. And more importantly, we found the visibility of PS shown on MRI might be an indication of the severity of PSIS.

Cortisol levels in central adrenal insufficiency: light and shade

Evaluating children or adolescents with central adrenal insufficiency (CAI) is a difficult task in clinical practice, especially in subjects with hypothalamic-pituitary diseases and partial ACTH deficiency, or in those with recent pituitary surgery or brain irradiation when the adrenal cortex may still be responsive to stress. In 2008, a meta-analysis reported a three-step approach for evaluating patients at risk for CAI with no acute illness. In particular, the authors recommended the evaluation of morning cortisol, a low dose ACTH test (LDST) and the "gold standard" insulin tolerance test or metyrapone test if the low LDCT was not diagnostic. Cortisol and ACTH secretion exhibit significant fluctuation throughout the day. The reference ranges supplied by labs are so wide that they only flag up extremely low cortisol levels. Interpreting the results correctly can be difficult for a physician without an experience in adrenal dysfunctions. The lack of uniformity in these cut-off levels could in part be attributed to differences in study populations, variability of dynainic tests, the use of different serum cortisol assays and dissimilar cut-off peak serum cortisol response indicative of a normal axis response and the difference in the clinical context in which the studies were done. Therefore, Laboratories have to advertise the need to establish reference values for given populations, both for basal or stimulated hormone levels. Failure to apply this rule may elicit false-positive and more critically, false-negative results. LDST (1 pg synthetic ACTH as iv bolus with measurement of serum cortisol) has been proposed as a sensitive test for the diagnosis of CAl. However, the advantage of LDST compared with the high dose test may be offset by the technical difficulties inherent to dilution of 250 pg ampoules. Clinical judgment remains imperative especially regarding the use of glucocorticoid supplementation during extreme stress.

Long-term follow-up of ipilimumab-induced hypophysitis, a common adverse event of the anti-CTLA-4 antibody in melanoma

OBJECTIVE

Few data are published on the long-term follow-up of ipilimumab-induced hypophysitis, a cytotoxic T-lymphocyte antigen 4 antibody. We characterized hypophysitis in terms of clinical signs, endocrinological profile, and imaging at diagnosis and during a long-term follow-up.

DESIGN AND PATIENTS

Fifteen patients, treated for malignant melanoma and who presented ipilimumab-induced hypophysitis, were observed between June 2006 and August 2012 in Timone Hospital, Marseille.

METHODS

Symptoms, pituitary function, and pituitary imaging at diagnosis of hypophysitis and during the follow-up were recorded.

RESULTS

Of 131 patients treated with ipilimumab or a placebo, 15 patients (10 mg/kg in 11/15) presented with hypophysitis (≥11.5%) at 9.5±5.9 weeks (mean±s.d.) after treatment start, occurring in 66% after the third infusion. The main initial symptoms were headache (n=13) and asthenia (n=11). All patients but one had at least one hormonal defect: thyrotroph (n=13), gonadotroph (n=12), or corticotroph (n=11) deficiencies. None had diabetes insipidus. Pituitary imaging showed a moderately enlarged gland in 12 patients. Clinical symptoms improved rapidly on high-dose glucocorticoids (n=11) or physiological replacement doses (n=4). At the end of follow-up (median 33.6 months, range 7-53.5), corticotroph deficiency remained in 13 patients, 11 recovered thyrotroph and ten gonadotroph functions. Pituitary imaging remained abnormal in 11 patients.

CONCLUSION

Ipilimumab-induced hypophysitis is a common side-effect with frequent hormonal deficiencies at diagnosis. Usually, hormonal deficiencies improved, except for corticotroph function. Patients receiving these immunomodulatory therapies should be closely monitored especially by systematic baseline hormone measurements after the third infusion and remain at a risk of adrenal insufficiency in the long-term.

A comparison of low-dose ACTH, glucagon stimulation and insulin tolerance test in patients with pituitary disorders

CONTEXT

Diagnosis of secondary adrenal insufficiency and GH deficiency requires evaluation by dynamic stimulation tests in most cases. Although insulin tolerance test (ITT) is accepted as the gold-standard test for the evaluation of both hypothalamo-pituitary-adrenal (HPA) and (GH)-IGF-1 axes, the test is cumbersome. In clinical practice, low-dose adrenocorticotrophic hormone (ACTH) stimulation test is a sensitive, safe and easily applicable alternative to ITT. Although it takes more time, glucagon stimulation test (GST) is also a good alternative to ITT and can evaluate both axes.

OBJECTIVE

The primary aim of this study was to compare the ITT, low-dose ACTH and GSTs in the evaluation of HPA and GH-IGF-1 axes in patients with pituitary disorders and to evaluate the repeatability of all three tests.

DESIGN

ITT, low-dose ACTH and GSTs were performed in all 129 patients, and the tests were repeated in 66 of these patients.

SETTING

Erciyes University Medical School, Department of Endocrinology.

PATIENTS OR OTHER PARTICIPANTS

One hundred and twenty-nine adult patients (76 women, 53 men) with pituitary disorder were included in the study.

MAIN OUTCOME MEASURE(S)

The cortisol and GH responses of patients to dynamic tests.

RESULTS

Peak cortisol levels obtained during ITT were significantly lower than the values obtained during both low-dose ACTH and GSTs. Peak cortisol levels obtained during the GST were lower than those found during the low dose ACTH stimulation test. Peak GH responses were found to be higher in GST than in ITT. All three tests had good reproducibility.

CONCLUSIONS

Any of 3 tests can be used in the evaluation of the HPA axis and either GST or the ITT can be used in the evaluation of the GH-IGF-1 axis but cut-off levels for the insufficiency of HPA or GH-IGF-1 axis should be individualized for each test.

Pituitary pars intermedia dysfunction does not necessarily impair insulin sensitivity in old horses

Equine pituitary pars intermedia dysfunction (PPID) has been associated with reduced insulin sensitivity in comparison with younger adult horses; however, the difference in insulin sensitivity between horses with PPID and aged-matched controls has not been well characterized. The objective of the study was to determine if aged horses with PPID had reduced insulin sensitivity and alterations in the insulin-mediated signaling pathways in the skeletal muscle when compared with healthy aged horses. Isoglycemic hyperinsulinemic clamp procedures were conducted in 12 horses that were classified as either PPID (n = 6; age: 25.0 ± 2.5 yr; mean ± standard deviation) or non-PPID, aged-matched controls (control) (n = 6; age: 25.7 ± 2.0 yr). Blood samples were taken before and during the clamp procedures to measure plasma glucose, insulin, and amino acid concentrations, and 2 muscle biopsies were collected from the gluteus medius muscle, one in the basal state and the second at the end of the clamp procedure (insulin-stimulated state). Plasma insulin concentrations increased ∼9-fold during the clamp compared with basal conditions (P < 0.001) in both groups. During the last 30 min of the clamp, the rate of glucose infusion required to maintain isoglycemia in horses with PPID was similar to that in the control horses (P = 0.67). The plasma concentrations of most indispensible amino acids were lower in the insulin-stimulated state than the basal state (P < 0.05). PPID status did not have an effect on the activation of factors associated with protein synthesis and breakdown; however, factors associated with protein synthesis had increased phosphorylation in the insulin-stimulated state, compared with basal. The results from this study provide evidence that PPID is not always associated with impairments in insulin sensitivity.

Rapid conversion of autoimmune hypophysitis to an empty sella with immediate lowering of the serum IgG4 level. Case Report

An 87-year-old man was admitted with fatigue, anorexia, vomiting, urinary incontinence, and a depressive state. His consciousness was evaluated as a 13 on the Glasgow Coma Scale (E4V3M6), and he had a body temperature of 36.4°C, a blood pressure of 91/60 mmHg, and a heart rate of 88 beats/min. General laboratory data were unremarkable except for a mildly elevated serum creatinine level. The plasma levels of growth hormone, luteinizing hormone, and follicle stimulating hormone were depressed. On the other hand, the prolactin level was elevated, and the corticotropin, cortisol, and thyrotropin levels were within the reference ranges. Cranial magnetic resonance imaging (MRI) revealed the marked swelling of the pituitary gland and the infundibular stalk, and the serum immunoglobulin G4 (IgG4) level was elevated (2.85 g/L; reference range, 0.048-1.05 g/L). Accordingly, a diagnosis of IgG4-related autoimmune hypophysitis (AH) was made. The patient responded well to glucocorticoid therapy, but the presence of diabetes insipidus was revealed and was subsequently controlled using desamino-D-arginine vasopressin (DDAVP). To our surprise, an empty sella was apparent on an MRI examination performed on Day 12. The patient's serum IgG4 level had decreased in a log-linear manner with a half-life of 30 days, which was comparable to the half-life of IgG4 in control subjects (21 days). At a 16-month follow-up examination, no substantial changes in the morphology or function of the pituitary gland were noted. In conclusion, an empty sella developed within 12 days after the clinical onset of AH in the present case, suggesting that an empty sella may be the direct outcome of AH. The conversion of AH to an empty sella was associated with an immediate shutdown of IgG4 overproduction.

Overweight/Obese adults with pituitary disorders require lower peak growth hormone cutoff values on glucagon stimulation testing to avoid overdiagnosis of growth hormone deficiency

CONTEXT

Obesity is associated with diminished GH secretion, which may result in the overdiagnosis of adult GH deficiency (GHD) in overweight/obese pituitary patients. However, there are no body mass index (BMI)-specific peak GH cutoffs for the glucagon stimulation test (GST), the favored dynamic test for assessing adult GHD in the United States.

OBJECTIVE

The objective of the study was to determine a peak GH cutoff level for the diagnosis of adult GHD in overweight/obese individuals using the GST.

DESIGN

This was a retrospective, cross-sectional study.

SETTING

The study was conducted at Massachusetts General Hospital and Oregon Health and Science University.

METHODS

A total of 108 subjects with a BMI ≥ 25 kg/m(2) were studied: healthy controls (n = 47), subjects with total pituitary deficiency (TPD) (n = 20, ≥ 3 non-GH pituitary hormone deficiencies), and subjects with partial pituitary deficiency (PPD) (n = 41, 1-2 non-GH pituitary hormone deficiencies).

INTERVENTION

The intervention consisted of a standard 4-hour GST.

MAIN OUTCOME MEASURES

The main outcome measure was peak GH level on GST.

RESULTS

Using the standard peak GH cutoff of 3 ng/mL, 95% of TPD cases (19 of 20), 80% of PPD (33 of 41), and 45% of controls (21 of 47) were classified as GHD. In receiver-operator characteristic curve analysis (controls vs TPD), a peak GH value of 0.94 ng/mL provided the greatest sensitivity (90%) and specificity (94%). Using a peak GH cutoff of 1 ng/mL, 6% of controls (3 of 47), 59% of PPDs (24 of 41), and 90% of TPDs (18 of 20) were classified as GHD. BMI (R = -0.35, P = .02) and visceral adipose tissue (R = -0.32, P = .03) negatively correlated with peak GH levels in controls.

CONCLUSION

A large proportion of healthy overweight/obese individuals (45%) failed the GST using the standard 3 ng/mL GH cutoff. Overweight/obese pituitary patients are at risk of being misclassified as GHD using this cutoff level. A 1-ng/mL GH cutoff may reduce the overdiagnosis of adult GHD in overweight/obese patients.

Evaluation of long-term pituitary functions in patients with severe ventricular arrhythmia: a pilot study

INTRODUCTION

Traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), stroke and cerebrovascular disease (CVD) are identified as risk factors for hypopituitarism. Pituitary dysfunction after TBI, SAH, and CVD may present in the acute phase or later in the course of the event. Chronic hypopituitarism, particularly growth hormone (GH) deficiency is related to the increased cardiovascular morbidity and mortality. In patients with serious ventricular arrhythmias, who need cardiopulmonary resuscitation, brain tissue is exposed to short-term severe ischemia and hypoxia. However, there are no data in the literature regarding pituitary dysfunction after ventricular arrhythmias.

PATIENTS AND METHODS

Forty-four patients with ventricular arrhythmias [ventricular tachycardia (VT), ventricular fibrillation (VF)] (mean age, 55.6 ± 1.8 years; 37 men, 7 women) were included in the study. The patients were evaluated after mean period of 21.2 ± 0.8 months from VT-VF. Basal hormone levels, including serum free triiodothyronine (fT3), free thyroxine (fT4), TSH, ACTH, prolactin, FSH, LH, total testosterone, estradiol, IGF-1, and cortisol levels were measured in all patients. To assess (GH)-insulin like growth factor-1 (IGF-1) axis, glucagon stimulation test was performed and 1 µg ACTH stimulation test was used for assessing hypothalamic-pituitary-adrenal (HPA) axis.

RESULTS

The frequencies of GH, gonadotropin and TSH deficiency were 27.2, 9.0, 2.2%, respectively. Mean IGF-1 levels were lower in GH deficiency group, but it was not statistically significant.

CONCLUSION

The present preliminary study showed that ventricular arrhythmias may result in hypopituitarism, particularly in growth hormone deficiency. Unrecognized hypopituitarism may be responsible for some of the cardiovascular problems at least in some patients.

Occurrence of IgG4-related hypophysitis lacking IgG4-bearing plasma cell infiltration during steroid therapy

Eight years after an episode of multiple IgG4-related disease, a pituitary mass with panhypopituitarism and a visual disturbance developed in a 70-year-old man under low-dose steroid therapy. A pituitary biopsy revealed findings of lymphocytic hypophysitis with the absence of IgG4-positive plasma cell infiltration. The serum IgG4 level was unremarkable. Although performing a pituitary biopsy and measuring the serum IgG4 level is crucial for making a diagnosis of IgG4-related hypophysitis, it is occasionally difficult to diagnose the disease in patients treated with steroid therapy, as observed in the present case. Based on a review of the diagnosis, conducting a careful assessment is required, especially in men and elderly patients thought to have solitary hypophysitis.

Pituitary stalk lesions: the Mayo Clinic experience

CONTEXT

Pituitary stalk lesions have various etiologies, often not clinically apparent. Pathological samples from these lesions are rarely obtained, because of the critical location and function of the hypophyseal stalk.

OBJECTIVES

The purpose of this study was to characterize the etiological spectrum of pituitary stalk lesions seen at Mayo Clinic Rochester over 20 years and to determine whether specific magnetic resonance imaging (MRI) characteristics could provide clinician guidance with regard to the etiology of infundibular lesions.

DESIGN

A retrospective review of patients with pituitary stalk lesions seen at Mayo Clinic Rochester between 1987 and 2006 was conducted. Demographic, clinical presentation, imaging, laboratory, operative, and pathology data were reviewed and are reported using descriptive statistics.

RESULTS

Of the 152 pituitary stalk lesions included, 49 (32%) were neoplastic, 30 (20%) were inflammatory, 13 (9%) were congenital anomalies, and 60 (39%) were of unclear etiology. Diabetes insipidus was diagnosed in 43 (28%) of the 152 patients, and 49 (32%) patients had at least one anterior pituitary hormone deficit. Secondary hypogonadism was the most common endocrine deficiency. Eleven of 13 congenital lesions were round in appearance and 5 of 7 patients with neurosarcoidosis confirmed by pathology had a uniformly thickened pituitary stalk on MRI. There were no statistically significant correlations between hypopituitarism and the pattern of enhancement or size of the lesion.

CONCLUSIONS

Findings on MRI remain key in guiding the diagnosis of pituitary stalk lesions, particularly when used in conjunction with other clinical clues. There are no good imaging predictors for hypopituitarism, making clinical evaluation of all patients with pituitary stalk lesions crucial.

Free and total plasma cortisol measured by immunoassay and mass spectrometry following ACTH₁₋₂₄ stimulation in the assessment of pituitary patients

CONTEXT

Measurement of plasma cortisol by immunoassay after ACTH₁₋₂₄ stimulation is used to assess the hypothalamic-pituitary-adrenal (HPA) axis. Liquid chromatography-tandem mass spectrometry (LCMS) has greater analytical specificity than immunoassay and equilibrium dialysis allows measurement of free plasma cortisol.

OBJECTIVE

We investigated the use of measuring total and free plasma cortisol by LCMS and total cortisol by immunoassay during an ACTH₁₋₂₄ stimulation test to define HPA status in pituitary patients.

DESIGN AND SETTING

This was a case control study conducted in a clinical research facility.

PARTICIPANTS

We studied 60 controls and 21 patients with pituitary disease in whom HPA sufficiency (n = 8) or deficiency (n = 13) had been previously defined.

INTERVENTION

Participants underwent 1 μg ACTH(1-24) intravenous and 250 μg ACTH₁₋₂₄ intramuscular ACTH₁₋₂₄ stimulation tests.

MAIN OUTCOME MEASURES

Concordance of ACTH₁₋₂₄-stimulated total and free plasma cortisol with previous HPA assessment.

RESULTS

Total cortisol was 12% lower when measured by immunoassay than by LCMS. Female sex and older age were positively correlated with ACTH₁₋₂₄-stimulated total and free cortisol, respectively. Measurements of total cortisol by immunoassay and LCMS and free cortisol 30 minutes after 1 μg and 30 and 60 minutes after 250 μg ACTH₁₋₂₄ were concordant with previous HPA axis assessment in most pituitary patients. However, free cortisol had greater separation from the diagnostic cutoff than total cortisol.

CONCLUSIONS

Categorization of HPA status by immunoassay and LCMS after ACTH₁₋₂₄ stimulation was concordant with previous assessment in most pituitary patients. Free cortisol may have greater clinical use in patients near the diagnostic threshold.

Circadian and circannual rhythms of cortisol, ACTH, and α-melanocyte-stimulating hormone in healthy horses

Cosinor analysis was used to evaluate whether pituitary and adrenal hormones exhibit circadian rhythmicity in horses. The effect of season and animal age on their respective rhythms was also determined. In addition, the usefulness of evaluating cortisol rhythmicity for the diagnosis of pituitary pars intermedia dysfunction (PPID) was assessed. Serum cortisol concentrations (P < 0.01), but not plasma ACTH or α-melanocyte-stimulating hormone (α-MSH), showed a significant circadian periodicity in horses. An effect of season on hormone concentration was observed with plasma ACTH and α-MSH concentration greater in the fall and cortisol concentration greater in the spring (P < 0.001). Age did not affect cortisol rhythm, but it did blunt the variation in cortisol concentration in horses, similar to what has been previously reported to occur in aged people and dogs. In addition, our results suggest that clinically and diagnostically normal, non-PPID-affected horses commonly have a loss of cortisol diurnal rhythm. Therefore, measurement of circadian rhythm is not an appropriate diagnostic test for PPID.

Somatic GNAS mutation causes widespread and diffuse pituitary disease in acromegalic patients with McCune-Albright syndrome

CONTEXT

McCune-Albright syndrome (MAS) is caused by sporadic mutations of the GNAS. Patients exhibit features of acromegaly. In most patients, GH-secreting pituitary adenomas have been held responsible for this presentation. However, surgical adenomectomy rarely eliminates excess GH production.

OBJECTIVE

The aim of this study was to elucidate pituitary pathology in patients with MAS and to explain the basis of failure of adenomectomy to eliminate GH hypersecretion.

DESIGN AND SETTING

We conducted a case series at the National Institutes of Health.

INTERVENTION(S)

Interventions included medical therapy and transsphenoidal surgery.

PATIENTS AND MAIN OUTCOME MEASURES

We studied clinical and imaging features and the histology and molecular features of the pituitary of four acromegalic MAS patients.

RESULTS

We identified widespread and diffuse pituitary gland disease. The primary pathological changes were characterized by hyperplastic and neoplastic change, associated with overrepresentation of somatotroph cells in structurally intact tissue areas. Genetic analysis of multiple microdissected samples of any type of histological area consistently revealed identical GNAS mutations in individual patients. The only patient with remission after surgery received complete hypophysectomy in addition to removal of multiple GH-secreting tumors.

CONCLUSIONS

These findings indicate developmental effects of GNAS mutation on the entire anterior pituitary gland. The pituitary of individual cases contains a spectrum of changes with regions of normal appearing gland, hyperplasia, and areas of fully developed adenoma formation, as well as transitional stages between these entities. The primary change underlying acromegaly in MAS patients is somatotroph hyperplasia involving the entire pituitary gland, with or without development of somatotroph adenoma. Thus, successful clinical management, whether it is medical, surgical, or via irradiation, must target the entire pituitary, not just the adenomas evident on imaging.

Central hypothyroidism in a patient with pituitary autoimmunity: evidence for TSH-independent thyroid hormone synthesis

CONTEXT

Acquired central hypothyroidism is rare, especially when isolated, and is typically associated with detectable, although biologically inactive, serum TSH.

OBJECTIVE

We describe a 56-yr-old woman with profound central hypothyroidism and partial central hypoadrenalism, in the absence of other endocrine abnormalities. In contrast to most cases of central hypothyroidism, serum TSH remained undetectable for 9 months before the initiation of thyroid hormone and hydrocortisone treatment. A test for pituitary autoantibody was moderately positive. Serum free T(4), serum T(3), and neck radioiodine uptake were low but detectable. The thyroid and pituitary glands appeared morphologically normal on neck ultrasound and head magnetic resonance imaging, respectively.

SETTINGS

The study was conducted in a tertiary academic medical center.

CONCLUSIONS

This case illustrates the variable clinical presentation of pituitary autoimmunity. The persistence of low but detectable thyroid hormone levels and radioiodine neck uptake in the absence of TSH suggests that significant TSH-independent thyroid hormone synthesis may occur in the normal thyroid.

Pituitary resistance to thyroid hormones: pathophysiology and therapeutic options

Thyroid hormone secretion suppresses the expression of thyroid stimulating hormone (TSH), both of which are strictly controlled by a negative feedback loop between the hypothalamus-pituitary and thyroid. Pituitary resistance to thyroid hormone (PRTH) is defined as resistance to the action of thyroid hormone that is more severe in the pituitary than at the peripheral tissue level. Although the molecular basis of PRTH is not well understood, the clinical issue mainly involves imbalance between the hypothalamus-pituitary and peripheral thyroid hormone responsivity, which may induce peripheral thyrotoxic phenomena. Here, we review the pathogenesis and molecular aspects of PRTH, present a single case with inappropriate TSH secretion suffering from thyrotoxicosis treated with PTU, and discuss the possible choice of therapeutic options to correct the imbalance of thyroid hormone responsivity in both the hypothalamus-pituitary and peripheral tissues.

GH response to oral glucose tolerance test: a comparison between patients with acromegaly and other pituitary disorders

CONTEXT

The cutoff value of nadir GH after an oral glucose tolerance test (OGTT) used to define disease remission in acromegaly is higher than that observed in healthy subjects. However, it is uncertain whether the impaired GH inhibition might be related to subtle abnormalities of GH secretion or to functional and/or anatomical hypothalamic-pituitary disconnection due to tumor per se or treatments.

OBJECTIVE

The objective of the study was to evaluate the impact of pituitary disorders other than acromegaly on GH response to OGTT. DESIGN, SUBJECTS, AND METHODS: Thirty-three patients (24 females and nine males, aged 50.1 ± 12.3 yr, 13 operated and two irradiated) with various hypothalamic-pituitary disorders (HPDs), 45 healthy subjects (controls), and 42 cured acromegalic patients matched for sex, age. and body mass index were investigated. All subjects were studied for IGF-I levels and GH levels before and during the OGTT.

RESULTS

In HPD patients mean postglucose nadir GH levels were 0.11 ± 0.08 μg/liter without any difference between patients treated with neurosurgery and/or radiotherapy and untreated and between patients with and without pituitary stalk alterations and/or hyperprolactinemia. Mean nadir GH values were similar in HPD patients and controls (0.11 ± 0.08 vs. 0.08 ± 0.08 μg/liter, P = 0.23) and lower than those found in cured acromegalic patients (0.18 ± 0.13 μg/liter, P = 0.02), although there was an overlapping in about half of patients.

CONCLUSIONS

Hypothalamic control of glucose-mediated GH suppression is not perturbed in patients with HPD. These data indicate that defective GH suppression to glucose that is found in acromegaly is unlikely to reflect a lack of integrity of hypothalamic function.

Lymphocytic hypophysitis with diabetes insipidus in a young man

BACKGROUND

A 29-year-old man was referred to a multidisciplinary pituitary clinic with a 3.5-year history of central diabetes insipidus, initially presumed to be idiopathic based on a normal MRI scan of the pituitary gland. Subsequent scanning revealed a suprasellar mass, which demonstrated progressive enlargement on serial imaging. He also developed hypogonadotropic hypogonadism.

INVESTIGATIONS

Measurement of levels of serum morning fasting cortisol, adrenocorticotropic hormone, total testosterone, luteinizing hormone, follicle-stimulating hormone, prolactin, insulin-like growth factor 1, TSH and free T(4), MRI of the pituitary gland and a transsphenoidal biopsy of a pituitary mass were performed.

DIAGNOSIS

Lymphocytic hypophysitis presenting with diabetes insipidus, with development of hypogonadotropic hypogonadism and a suprasellar mass.

MANAGEMENT

The patient was treated with intranasal desmopressin and transdermal testosterone. The underlying lymphocytic hypophysitis was initially managed conservatively with serial MRI and visual field testing. No immunosuppressant medication was given and, aside from the diagnostic transsphenoidal biopsy, no surgical intervention was required. He subsequently developed secondary hypothyroidism, secondary adrenal insufficiency and growth hormone deficiency. These disorders were managed with levothyroxine and prednisone.

[Diagnosis and treatment of patients with primary "empty" sella turcica syndrome at the stage of sanatorium-and-spa rehabilitation]

The authors report the first attempt to develop the treatment strategy for patients with primary "empty" sella turcica syndrome based at a health resort facility. It is shown that combined therapy including radon baths and acupuncture at specific auricular points makes it possible to improve functioning of the pituitary-ovarian system, decrease body weight, normalize blood prolactin level, eliminate visceral obesity, enhance tissue sensitivity to insulin, reduce hyperinsulimenia and fertility problems (anovulation, hyperandrogenism, and hypoluteinism) associated with insulin resistance.

Diagnosis of adrenal insufficiency using the GHRP-6 Test: comparison with the insulin tolerance test in patients with hypothalamic-pituitary-adrenal disease

The insulin tolerance test (ITT) is considered the gold standard for the diagnosis of adrenal insufficiency (AI). However, the test is unpleasant to perform and has the risk of serious complications. We therefore evaluated the clinical applicability of GHRP6, which is a known activator of the hypothalamic-pituitary-adrenal (HPA) axis, to test for AI. For this purpose a comparative clinical study was designed. Forty-nine patients with suspected dysfunction of the HPA axis and 20 healthy controls were enrolled. The ITT was performed in patients, and GHRP6 (1 microg/kg) testing in patients and controls. Serum cortisol over 90 min after GHRP6, in comparison to the ITT, was the main outcome measure. Thirty-one patients had a peak cortisol response of less than 500 nmol/l during ITT and were considered adrenal insufficient. For GHRP6, the mean cortisol peak was 227+/-25.7 nmol/l in the AI group versus 395+/-35.3 nmol/l in the adrenal sufficient (AS) group. ROC analysis of peak cortisol levels during GHRP6 test suggested an optimal threshold of 299 nmol/l for the diagnosis of AI (Sens. 71.0%, Spec. 77.8%). Applying upper (416 nmol/l) and lower (137 nmol/l) thresholds with high specificities in combination with early morning cortisol established the diagnosis in nearly half of the patients, even when the GHRP6 test is limited to 30 min duration. GHRP6 led to significant activation of the HPA axis with no detectable side effects, but had limited accuracy in comparison to the ITT.

The effect of body mass index on the diagnosis of GH deficiency in patients at risk due to a pituitary insult

OBJECTIVES

Diminished GH response to stimulation has been demonstrated in obesity, leading to erroneous diagnosis of GH deficiency. The aim of this study was to evaluate the influence of body mass index (BMI) on GH responsiveness in patients at risk for pituitary function deficits.

METHODS

A total of 59 healthy subjects and 75 patients with a pituitary insult underwent insulin tolerance test or pyridostigmine+GHRH test in order to assess GH secretory reserve. Normal subjects and patients were classified as normal weight (BMI <24.9 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)), and obese (BMI >30 kg/m(2)).

RESULTS

All normal individuals with BMI <24.9 kg/m(2) demonstrated adequate GH responses, while three of the 21 overweight (14.3%) and nine of the 28 obese subjects (32.1%) did not respond to GH stimulation. Among patients, four of 14 (28.6%) with BMI <24.9 kg/m(2), 18 of 22 (81.8%) who were overweight, and 28 of 39 (71.7%) who were obese did not respond to GH stimulation. Of the 46 nonresponder patients with increased BMI, nine (19.6%) had normal insulin-like growth factor 1 (IGF1) values and no other pituitary hormone deficits, raising questions about the accuracy of somatotroph function assessment, while all nonresponders with BMI <24.9 kg/m(2) had low IGF1 values and panhypopituitarism.

CONCLUSIONS

Our results indicate that BMI >25 kg/m(2) has a negative effect on GH response not only in normal healthy subjects but also in patients at risk for pituitary function deficit as well. Parameters such as IGF1 levels and anterior pituitary deficits should be taken into account to accurately assess GH status in these patients.

[Isolation of pituitary autoantigen by affinity chromatography]

INTRODUCTION

In sera of pituitary disease patients and other autoimmune endocrine disease are detectable pituitary autoantibodies. Until now characterization of pituitary antigen is still unknown. The aim of our study was isolation and characterization of pituitary autoantigen by affinity chromatography. For isolation we have used microsomal fraction of human pituitary.

MATERIAL AND METHODS

For immunoglobulins isolation have been used sera of pituitary disease, Addison disease and Graves-Basedow disease patients with detectable pituitary autoantibodies. For pituitary antigen isolation have been used microsomal fraction of human pituitary obtained by ultracentrifugation and solubilisation. Immunoglobulins isolation was performed on Sepharose 4B-Protein A. Immunosorbent was performed on CNBr-activated Cl-4B Sepharose. Desorbtion was conducting by 0.2 mol/L glicine and 1 mol/L, 3 mol/L guanidine. The estimation of isolated proteins was performed by immunoblotting.

RESULTS

Isolation of immunoglobulins from patients sera was done 12 times receiving from 8.5 up to 13.5 mg of IgG from 1-1.5 ml of sera. In desorbtion we have received from 0.026 up to 0.150 mg of antigen proteins. For molecular weight estimation isolated proteins have been labeled by (125)I and run on SDS/PAGE with autoradiography. Autoradiography shown us two lines with 67 kDa and 55 kDa and low weight protein line.

CONCLUSIONS

Isolation of pituitary autoantigen by affinity chromatography shown two different antigen proteins with 67 kDa and 55 kDa.

A subnormal peak cortisol response to stimulation testing does not predict a subnormal cortisol production rate

INTRODUCTION

The decision to commence lifelong glucocorticoid replacement therapy is often based on a cortisol stimulation test. We investigated the relationship between the peak cortisol response to insulin-induced hypoglycemia and daily cortisol production rate (CPR) to ascertain whether provocative tests are accurate in indicating the need to initiate lifelong glucocorticoid replacement.

PATIENTS AND METHODS

Ten patients (five male; mean age, 44 +/- 13 yr) with pituitary disease and with demonstrably suboptimal peak cortisol response (350-500 nmol/liter) to insulin-induced hypoglycemia, underwent CPR measurement by isotope dilution using gas chromatography-mass spectrometry and 24-h urinary free cortisol (UFC).

RESULTS

The median baseline and peak cortisol attained with hypoglycemia were 284 (164-323) and 473.5 (366-494) nmol/liter, respectively. A strong positive correlation was seen between peak stimulated cortisol and CPR (adjusted for body surface area) (r = 0.75; P = 0.02), and in all patients CPR [4.6 (2.9-15.1) mg/d x m(2)] was within the reference range (2.1-12 mg/d x m(2)) or elevated (one patient). A wide range was found for 24-h UFC [116.5 (20.5-265.9) nmol/liter] in this group of patients, and this parameter lacked significant correlation with either serum cortisol concentration or CPR.

CONCLUSION

This is the first study to demonstrate a significant correlation between CPR and peak cortisol values during hypoglycemic challenge. An inadequate cortisol response to hypoglycemia suggests the need for glucocorticoid cover at times of stress, but these data indicate that a suboptimal peak cortisol does not equate to a low CPR and should not be an automatic indication for lifelong glucocorticoid replacement therapy. UFC bears no relation to serum cortisol or CPR and is therefore unhelpful in assessment of such patients.

Diagnosis of growth hormone deficiency in adults: provocative testing with GHRP6 in comparison to the insulin tolerance test

The aim of the study was to evaluate the clinical applicability of growth hormone releasing peptide 6 (GHRP6) for the diagnosis of GH deficiency in adults. Forty-nine patients with suspected hypothalamic or pituitary disease underwent both ITT and GHRP6 (1 microg/kg) testing. In addition, 20 healthy controls were tested by GHRP6 only. Blood samples were analyzed for GH levels. Thirty patients had a GH peak response of less than 3 microg/l during ITT and were considered growth hormone deficient (GHD). For the GHRP6 test, the GH mean peak was 3.0 microg/l (+/-0.8, 0.5-20.9) in the GHD group vs. 14.8 microg/l (+/-4.7, 1.8-95.3) in the growth hormone sufficient (GHS) group. Receiver operating characteristics (ROC) analysis suggested an optimal peak GH cut-point of 3.5 microg/l with 80% sensitivity and 95% specificity. Applying upper (11.3 microg/l) and lower (3.5 microg/l) cutoffs with high specificities established the diagnosis in nearly two third of the patients. During administration of GHRP6 no side effects were observed. GHRP6 alone as a provocative test is highly specific, but with limited sensitivity for the diagnosis of GH deficiency in adults. Using upper and lower cutoffs, further testing by ITT may be necessary in only one-third of patients.

Diagnosis of secondary adrenal insufficiency in patients with hypothalamic-pituitary disease: comparison between serum and salivary cortisol during the high-dose short synacthen test

OBJECTIVE

Accurate assessment of adrenal function is essential in patients with hypothalamic-pituitary-adrenal (HPA) disease. The measurement of salivary cortisol (SaC) instead of serum cortisol (SeC) offers several advantages, such as the determination of the free hormone. We evaluated the diagnostic value of SeC and SaC both unstimulated and during a high-dose short synacthen test (HDT) in comparison to the insulin tolerance test (ITT).

DESIGN

Comparative study between 2005 and 2007.

METHODS

Fifty-five patients with HPA impairment and 21 healthy controls were enrolled. Samples were collected in the early morning and over 120 min during the HDT. Receiver operating characteristic analysis revealed individual thresholds for four HDT periods (0-30, 0-60, 0-90, and 0-120 min).

RESULTS

The ITT identified 30 subjects as adrenal insufficient. With respect to the four HDT periods, sensitivity and specificity were 67-79% and 71-88% for SeC, compared with 63-72% and 72-86% for SaC. If upper and lower thresholds (with specificities >95%) were applied, patients were diagnosed in 40-45% by SeC and in 25-31% by SaC. The combination of basal cortisol and HDT allowed a diagnosis in 47-49% (SeC) and in 42-45% (SaC) respectively.

CONCLUSION

We suggest the determination of basal SeC or SaC as first-line test. In comparison to the ITT, the HDT has only limited value in screening for alterations of the HPA axis. If the HDT is performed, sampling may be limited to 30 min post-synacthen, using either SeC or SaC. Due to the ease of collection and the independence of binding proteins, SaC may be preferable.

Pituitary and stalk lesions (infundibulo-hypophysitis) associated with immunoglobulin G4-related systemic disease: an emerging clinical entity

Inflammatory lesions of the pituitary gland are rarely encountered. Recently, the concept of immunoglobulin G4 (IgG4)-related systemic disease was proposed in Japan, and more than 20 cases have been reported as possibly associated with infundibulo-hypophysitis since 2000. We herein review such case reports in the published literature and in the abstracts of scientific meetings. Almost all cases involved middle-aged to elderly men presenting with various degrees of hypopituitarism and diabetes insipidus and demonstrating a thickened pituitary stalk and/or pituitary mass. These structures shrank remarkably in response to glucocorticoid therapy, even in a lower dose range similar to that prescribed as a replacement for adrenocortical insufficiency. Some of the anterior pituitary insufficiencies were also resolved by glucocorticoid administration. The presence of IgG4-related systemic disease and an elevated serum IgG4 level before glucocorticoid therapy were the main clues to a correct diagnosis of IgG4-related infundibulo-hypophysitis. Autoimmunity is suggested but not yet established to play a role in the pathogenesis for IgG4-related systemic disease. The fact that hypertrophic pachymeningitis and para-sinusitis accompanied some cases suggested that both sellar and parasellar structures are involved in the chronic inflammation. We therefore classify this disorder not as a variant form of primary autoimmune hypophysitis but as a secondary form of infundibulo-hypophysitis associated with IgG4-related systemic disease.

Novel autoantigens in autoimmune hypophysitis

BACKGROUND

Pituitary autoantibodies are found in autoimmune hypophysitis and other conditions. They are a marker of pituitary autoimmunity but currently have limited clinical value. The methods used for their detection lack adequate sensitivity and specificity, mainly because the pathogenic pituitary autoantigen(s) are not known and therefore antigen-based immunoassays have not been developed.

OBJECTIVES

This study aimed to identify novel pituitary autoantigens using sera as probes in proteomic assays. We also compared immunoblotting and immunofluorescence methods for their accuracy in diagnosing autoimmune hypophysitis.

STUDY DESIGN AND SUBJECTS

Twenty-eight sera from autoimmune hypophysitis cases (14 histologically proven and 14 clinically suspected) were compared to 98 sera from controls, which included 14 patients with pituitary adenomas, 48 with autoimmune thyroiditis (15 Graves' disease and 33 Hashimoto's thyroiditis) and 36 healthy subjects.

METHODS

All sera were tested against human pituitary cytosolic proteins separated by one-dimensional (1D) gel electrophoresis. The band recognition was analysed statistically to detect molecular weight regions preferentially recognized by hypophysitis sera. 2D gel immunoblotting and mass spectrometry were then used to sequence the protein spots of interest. Sera were also tested by immunofluorescence for their recognition of Macaca mulatta pituitary sections.

RESULTS

A single region in the 25-27-kDa range was recognized more often by hypophysitis cases than healthy subjects (P = 0.004) or patients with pituitary adenomas (P = 0.044). This region contained two novel candidate autoantigens: chromosome 14 open reading frame 166 (C14orf166) and chorionic somatomammotrophin. Immunoblotting positivity for the 25-27-kDa region yielded greater sensitivity (64%vs. 57%) and specificity (86%vs. 76%) than immunofluorescence in predicting histologically proven hypophysitis, although the performance was still inadequate to make immunoblotting a clinically useful test.

CONCLUSION

The study reports two novel proteins that could act as autoantigens in autoimmune hypophysitis. Further studies are needed to validate their pathogenic role and diagnostic utility.

Diagnostic strategy for growth hormone deficiency: relevance of IGF-1 determination as a screening test

BACKGROUND

Adult growth hormone (GH) deficiency must be diagnosed before prescribing therapeutic recombinant human GH. We studied the clinical relevance of a diagnostic strategy for growth hormone deficiency (GHD) using IGF-1 determination as a first step.

METHODS

In 2000 and 2001, we tested 142 adult patients with hypothalamo-pituitary disorders for somatotropic function using Insulin Tolerance Test (ITT), the reference test for the diagnosis of GHD, with concomitant Insulin-like growth factor-1 (IGF-1) determination, a marker of somatotropic function. Patients were classified as GHD (peak GH concentration<3 ng/ml with the ITT) or normal.

SETTING

Monocenter prospective study in a tertiary referral center.

RESULTS

GHD was diagnosed in 61 subjects. Using a ROC curve, a threshold IGF-1 concentration of 175 ng/ml yielded a negative predictive value of 89+/-5%. A diagnostic strategy with IGF-1 determination as the first step followed by ITT for patients with an IGF-1 concentration below 175 ng/ml missed five of the 61 GHD patients, avoided 46/142 ITT and reduced the cost of diagnosis by 15%.

CONCLUSION

We propose the use of a strategy consisting of IGF-1 determination followed, if below 175 ng/ml by confirmatory ITT to diagnose GHD in adults.

Adrenocorticotropin concentration following administration of thyrotropin-releasing hormone in healthy horses and those with pituitary pars intermedia dysfunction and pituitary gland hyperplasia

OBJECTIVE

To compare the effect of thyrotropin-releasing hormone (TRH) administration on endogenous ACTH concentrations in healthy horses and those with pituitary pars inter-media hyperplasia and compare the test with the dexamethasone suppression test (DST).

DESIGN

Prospective case series.

ANIMALS

15 horses with clinical signs of pituitary pars intermedia dysfunction (PPID), 4 horses with equivocal signs of PPID, and 29 horses without signs of PPID.

PROCEDURES

ACTH concentrations prior to and after administration of TRH were measured 61 times in 48 horses. Results of the DST (cortisol response) were compared with those of the TRH test in 29 horses. Thirty-three horses (24 with no clinical signs of PPID, 5 with clinical signs of PPID, and 4 with equivocal clinical signs of PPID) were euthanized and necropsied and their pituitary glands evaluated.

RESULTS

ACTH concentrations increased in all horses, but magnitude and duration of increase were significantly higher in horses with PPID. Endogenous ACTH concentrations were influenced by season. The ACTH baseline concentrations and response to TRH were not correlated with results of the DST. Results of DST were abnormal only in clinically abnormal horses or those with pars intermedia hyperplasia, but were within reference range in 17 of 26 tests in these horses.

CONCLUSIONS AND CLINICAL RELEVANCE

The ACTH response to TRH is a useful test for diagnosis of pituitary gland hyperplasia, particularly in horses in which baseline ACTH concentrations are within reference range. The DST was specific but not sensitive and was inconsistent for individuals, and results often did not agree with the TRH test response.

Long-term effects of growth hormone (GH) on bone mineral status and bone turnover markers in patients with isolated GH deficiency and multiple pituitary hormone deficiency

OBJECTIVE

This study was designed to assess the long-term effects of growth hormone (GH) replacement therapy on bone mass and bone turnover markers in children with isolated GH deficiency (IGHD) and multiple pituitary hormone deficiency (MPHD).

MATERIALS AND METHODS

Fifty children (35 IGHD, 15 MPHD) receiving GH replacement therapy were enrolled in the study. The patients were followed for 38.6 +/- 15.7 months (1-5 years). Bone mineral density (BMD) of the lumbar region and bone turnover markers [PTH, osteocalcin, bone-specific alkaline phosphatase (boneALP), and the carboxyterminal propeptide of type-1 collagen (CPP-I)] were assessed annually.

RESULTS

The height standard deviation score (SDS) of patients with IGHD and MPHD at diagnosis was statistically significant (P = 0.012), and the change in height SDS during 3 years (Deltaheight SDS(3 years)) was statistically similar between these two groups (P = 0.651). The BMD z-scores of the two groups were comparable at the start of GH therapy (P = 0.083), and then increased in both groups similarly during 5 years of GH replacement therapy (F = 0.349, P = 0.567). When the BMD z-scores during 5 years of GH therapy were analysed in the IGHD and MPHD groups separately, it was found that the BMD z-score increased significantly in IGHD (P < 0.001) but the increase was not significant in MPHD (P = 0.140). Multiple regression analysis showed that the change in BMD z-score during 3 years of GH therapy (DeltaBMD z-score(3 years)) was predicted by the BMD z-score and height SDS at the start of GH therapy and by Deltaheight SDS(3 years) in the IGHD group (t = -2.582, P = 0.02; t = 2.322, P = 0.034 and t = 2.908, P = 0.01, respectively). Age and BMD z-score and height SDS at diagnosis were found to have predictive values for the DeltaBMD z-score(3 years) (t = -3.652, P = 0.022; t = -4.073, P = 0.015 and t = 3.389, P = 0.028, respectively) in the MPHD group. The changes in boneALP, osteocalcin, CPP-1 and PTH levels during the therapy were statistically similar between the IGHD and MPHD groups.

CONCLUSION

BMD increased during GH therapy in the IGHD and MPHD groups. GH had a positive effect on bone mass in the short as well as the long term. Early diagnosis and treatment could improve peak bone mass in patients with MPHD. The time and dose of sex steroids for pubertal induction and progression, which mimics physiological secretion, might also contribute to bone accretion in patients with MPHD.

Multicenter evaluation of a rapid electrochemiluminescent adrenocorticotropic hormone (ACTH) immunoassay

BACKGROUND

Measuring plasma adrenocorticotropic hormone (ACTH) is a key step in the differential diagnosis of hypothalamic-pituitary-adrenal disorders.

METHODS

The recently developed electrochemiluminescence Elecsys ACTH immunoassay (Roche Diagnostics, Mannheim, Germany) was evaluated at six clinical laboratories on the Modular E170 and/or the Elecsys 2010 (Roche Diagnostics) immunoanalysers.

RESULTS

The within-run and between-run imprecision was <or=1.9% and <or=5%, respectively (concentration level 12-971 ng/L). Functional sensitivity was at least 1.8 ng/L. The Elecsys assay correlated well with two established ACTH immunoradiometric assays (Brahms ACTH RIA and Nichols ACTH IRMA) and with the Immulite ACTH assay. Reference values for the Elecsys ACTH assay, determined as the percentile 5 to 95 (2.5 to 97.5) interval in 354 adults without disorder with impact on the hypothalamic-pituitary-adrenal axis, were between 7.2 and 63 ng/L (5.6 and 76 ng/L). The clinical sensitivity of the Elecsys ACTH assay in 57 patients with confirmed disorders of the pituitary-adrenal axis was comparable to the established Brahms ACTH assay.

CONCLUSION

The non-isotopic Elecsys ACTH immunoassay provides precision and reliability in combination with reduced turnaround time.