Early assessment of postoperative adrenal function is necessary after adrenalectomy for mild autonomous cortisol secretion.

BACKGROUND: The diagnostic threshold for mild autonomous cortisol secretion using low dose, overnight, dexamethasone suppression testing is recognized widely as a serum cortisol ≥1.8 mcg/dL. The degree to which these patients require postoperative glucocorticoid replacement is unknown. METHODS: We reviewed adult patients with corticotropin (ACTH)-independent hypercortisolism who underwent unilateral laparoscopic adrenalectomy for benign disease with a dexamethasone suppression testing ≥1.8 mcg/dL at our institution from 1996 to 2018. Patients with a dexamethasone suppression testing of 1.8 to 5 mcg/dL were compared with those with a dexamethasone suppression testing >5 mcg/dL. RESULTS: We compared 68 patients with a preoperative dexamethasone suppression testing of 1.8 to 5 mcg/dL to 53 patients with a preoperative dexamethasone suppression testing >5 mcg/dL. Preoperative serum ACTH (mean 10.0 vs 9.2 pg/mL), adenoma size (mean 3.4 vs 3.5 cm), and side of adrenalectomy (37 and 47% right) were similar between groups (P > .05 each). Patients with a dexamethasone suppression testing 1.8 to 5 mcg/dL were older (mean values 58 ± 11 vs 52 ± 16 years ; P = .01), less likely to be female (63 vs 81%; P = .03), had greater body mass indexes (33.1 ± 8.4 vs 29.1 ± 5.6; P = .01), and had lesser 24 hour preoperative urine cortisol excretions (32.6 ± 26.7 vs 76.1 ± 129.4 mcg; P = .03). Postoperative serum cortisol levels were compared in 22 patients with a dexamethasone suppression testing of 1.8 to 5 mcg/dL to 14 patients with a dexamethasone suppression testing >5 mcg/dL. Those with dexamethasone suppression testing 1.8 to 5 mcg/dL had greater postoperative serum cortisol levels (8.0 ± 5.7 vs 5.0 ± 2.6 mcg/dL; P = .03), were less likely to be discharged on glucocorticoid replacement (59% vs 89%; P = .003), and had a decreased duration of treatment (4.4 ± 3.8 vs 10.7 ± 18.0 months; P = .04). CONCLUSION: Assessment of early postoperative adrenal function with mild autonomous cortisol secretion is necessary to minimize unnecessary glucocorticoid replacement.

TRH-induced secretion of adrenocorticotropin and cortisol in dogs with pituitary-dependent hypercortisolism.

BACKGROUND: In dogs, spontaneous Cushing's syndrome is most often pituitary-dependent and caused by hypersecretion of adrenocorticotropic hormone (ACTH), resulting in increased adrenocortical glucocorticoid secretion similar to horses. In horses with Cushing's syndrome (or pituitary pars intermedia dysfunction [PPID]) a thyrotropin-releasing hormone (TRH) stimulation test can be used for diagnosis, as TRH administration results in increased circulating ACTH and cortisol concentrations in affected horses. OBJECTIVE: The aim of this study was to investigate the effect of TRH administration on the circulating ACTH and cortisol concentrations in dogs with pituitary-dependent hypercortisolism (PDH). METHODS: Ten clinically normal control dogs and 10 dogs with PDH, all client owned, underwent a TRH stimulation test with measurement of plasma concentrations of ACTH and cortisol, before and after intravenous administration of 10 µg TRH/kg bodyweight. RESULTS: Plasma ACTH concentration did not rise significantly after TRH stimulation, neither in PDH dogs nor in clinically normal dogs. In contrast, the plasma cortisol concentration did increase significantly after TRH stimulation in both groups (p = .003 in PDH and p < .001 in control). Immunohistochemistry of normal adrenal glands demonstrated the presence of TRH receptors in the whole adrenal cortex. CONCLUSIONS: The results of this study demonstrate that the TRH stimulation test should be rejected as a tool to diagnose PDH in dogs. The observed TRH-induced increase in plasma cortisol concentration without a significant rise in plasma ACTH concentration may be explained by a direct effect of TRH on adrenocortical cells mediated by adrenocortical TRH receptors.

Hypothalamo-pituitary-adrenal axis after a single epidural triamcinolone injection.

PURPOSE: To quantify adrenocorticotropin and cortisol secretion after epidural glucocorticoid injection. METHODS: Eight men (ages 25-63 year) were studied at baseline, 1, 4, and 12 weeks after triamcinolone (80 mg) injection epidurally. Adrenocorticotropin (pg/mL) and cortisol (µg/dL) were measured every 10 min for 4 h, and after Corticotropin-releasing hormone (CRH) (1 µg/kg) injection. RESULTS: Epidural triamcinolone markedly suppressed: (1) pre-CRH injection ACTH (from 18 ± 3.1 to 4.8 ± 0.4: P < 0.01) and cortisol (from 12.2 ± 1.6 to 1.6 ± 0.3: P < 0.0001) at week 1, with recovery at 4 weeks, and (2) CRH-stimulated 3-h summed ACTH (from 633 ± 116 to 129 ± 10 pg/mL, P < 0.0001), and 3-h summed cortisol at week 1 (from 385 ± 29 to 56 ± 22 µg/dL, P < 0.0001) and 4 weeks (284 ± 53; P < 0.01). Serum cortisol was <18 µg/dL in eight of eight men at 4 weeks, and six of eight men at week 12. Urinary-free cortisol (µg/24 h) remained low at week 12: baseline (60 ± 6.5); week 1 (9.0 ± 1.3, P < 0.01); week 4 (36 ± 8.6) and week 12 (38 ± 4.1). Urinary cortisol/cortisone ratios rose at week 4 only. Serum triamcinolone peaked at week 1 (16/16 samples), declining at week 4 (13/16 samples) and week 12 (6/16 samples). LIMITATIONS: Relatively small group. CONCLUSION: Epidural triamcinolone suppresses unstimulated and CRH-stimulated ACTH and cortisol secretion for 1-4 weeks but urinary free cortisol ≥12 weeks. Suppression of ACTH and cortisol after glucocorticoid treatment is thus complex.

Measuring cortisol in serum, urine and saliva - are our assays good enough?

Cortisol is a steroid hormone produced in response to stress. It is essential for maintaining health and wellbeing and leads to significant morbidity when deficient or present in excess. It is lipophilic and is transported bound to cortisol-binding globulin (CBG) and albumin; a small fraction (∼10%) of total serum cortisol is unbound and biologically active. Serum cortisol assays measure total cortisol and their results can be misleading in patients with altered serum protein concentrations. Automated immunoassays are used to measure cortisol but lack specificity and show significant inter-assay differences. Liquid chromatography - tandem mass spectrometry (LC-MS/MS) offers improved specificity and sensitivity; however, cortisol cut-offs used in the short Synacthen and Dexamethasone suppression tests are yet to be validated for these assays. Urine free cortisol is used to screen for Cushing's syndrome. Unbound cortisol is excreted unchanged in the urine and 24-h urine free cortisol correlates well with mean serum-free cortisol in conditions of cortisol excess. Urine free cortisol is measured predominantly by immunoassay or LC-MS/MS. Salivary cortisol also reflects changes in unbound serum cortisol and offers a reliable alternative to measuring free cortisol in serum. LC-MS/MS is the method of choice for measuring salivary cortisol; however, its use is limited by the lack of a single, validated reference range and poorly standardized assays. This review examines the methods available for measuring cortisol in serum, urine and saliva, explores cortisol in disease and considers the difficulties of measuring cortisol in acutely unwell patients and in neonates.

Adrenal Cushing syndrome with detectable ACTH from an unexpected source.

Mixed corticomedullary adrenal tumours (MCMT) are rare. We describe the second reported case of a male patient presenting with hypertension and Cushing syndrome with MCMT. A man aged 48 years presented with hypertension and signs of Cushing syndrome. 24-hour urine cortisol was elevated, with detectable adrenocorticotropic hormone (ACTH). A high-dose dexamethasone suppression test indicated an adrenal or ectopic Cushing syndrome. Plasma metanephrines were normal. A 3 cm left adrenal mass was identified without potential ectopic sources of ACTH on imaging. After induction of anaesthesia for laparoscopic adrenalectomy, the patient developed resistant hypertension with stress-dose hydrocortisone administration. Surgery was cancelled and repeat testing revealed elevated plasma metanephrines. α-Blockade was administered for a presumed coexisting pheochromocytoma, and the patient underwent adrenalectomy. Pathology revealed an MCMT. This case highlights the importance of a thorough biochemical evaluation in patients with adrenal masses to rule out multiple hormone producing tumours.

No Untoward Effect of Long-Term Ketoconazole Administration on Electrocardiographic QT Interval in Patients with Cushing's Disease.

Ketoconazole is listed among drugs that prolong QT interval and may increase the risk of torsade de pointes, a severe ventricular arrhythmia. This compound has recently been approved for treatment of Cushing's syndrome, a severe endocrine disorder. These patients harbour several risk factors for prolonged QT interval, for example hypokalaemia and left ventricular hypertrophy, but no study has evaluated whether administration of ketoconazole affects their QT interval. The aim of this study was to assess the QT interval in patients with Cushing's disease during long-term administration of ketoconazole. Electrocardiograms from 15 patients with Cushing's disease (12 women, 3 men, age: 37.8 ± 2.66 years) on ketoconazole treatment (100 mg-800 mg qd) for 1 month to 12 years were reviewed retrospectively. QT interval was measured and corrected for heart rate (QTc). Measurements before and during ketoconazole treatment were compared and any abnormal QTc value recorded. Concurrent medical therapies were also documented. On average, QTc was superimposable before and during ketoconazole treatment (393.2 ± 7.17 versus 403.3 ± 6.05 msec. in women; 424.3 ± 23.54 versus 398.0 ± 14.93 msec. in men, N.S.). QTc normalized on ketoconazole in one man with prolonged QTc prior to treatment; no abnormal QTc was observed in any other patient during the entire observation period, even during concurrent treatment with other QT-prolonging drugs. In conclusion, long-term ketoconazole administration does not appear to be associated with significant prolongation of QT interval in patients with Cushing's disease. ECG monitoring can follow recommendations drawn for other low-risk QT-prolonging drugs with attention to specific risk factors, for example hypokalaemia and drug interactions.

Ectopic adrenocorticotropic hormone and corticotropin-releasing hormone co-secreting tumors in children and adolescents causing cushing syndrome: a diagnostic dilemma and how to solve it.

CONTEXT: Ectopic ACTH/CRH syndrome is a rare cause of Cushing syndrome (CS), especially in children. The localization, work-up, and management of ACTH/CRH-secreting tumors are discussed. SETTING: A retrospective study was conducted of patients under 21 years of age evaluated at the National Institutes of Health (NIH) for CS and diagnosed with ectopic ACTH/CRH-secreting tumors during the period 2009-2014. PATIENTS: Seven patients with ectopic ACTH/CRH CS are included in this study with a median age 13.6 years (range 1-21), and 3 are female. MEASUREMENTS: Clinical, biochemical, radiological features, treatment, and histological findings are described. RESULTS: Seven patients were found to have ACTH/CRH-secreting tumors, all with neuroendocrine features. The site of the primary lesion varied: pancreas (3), thymus (2), liver (1), right lower pulmonary lobe (1). PATIENTS underwent biochemical evaluation for CS, including diurnal serum cortisol and ACTH levels, urinary free cortisol levels (UFC), and CRH stimulation tests. All patients underwent radiological investigations including MRI, CT, and PET scan; imaging with octreotide and 68 gallium DOTATATE scans were performed in individual cases. Five patients underwent inferior petrosal sinus sampling; 4 patients had sampling for ACTH and CRH levels from additional sites. Three patients underwent trans-sphenoidal surgery (TSS), and 3 patients required bilateral adrenalectomy. Three patients (43%) died due to metastatic disease, demonstrating the high mortality rate. One of the unique findings in these seven patients is that in each case, their neuroendocrine tumors were ultimately proven to be co-secreting ACTH and CRH. This explains the enigmatic presentation, in which 3 patients initially thought to have Cushing's disease (CD) with corresponding pituitary hyperplasia underwent TSS prior to the correct localization of the causative tumor. CONCLUSIONS: Ectopic ACTH/CRH co-secreting tumors are extremely rare in children and adolescents. The diagnosis of this condition is frequently missed and is sometimes confused with CD due to the effect of CRH on the pituitary.

Chronic fatigue in adult survivors of childhood cancer: associated symptoms, neuroendocrine markers, and autonomic cardiovascular responses.

BACKGROUND: Chronic fatigue (CF) is a common late effect after childhood cancer. OBJECTIVE: Based on findings among patients with the chronic fatigue syndrome (CFS), this study explored symptoms, neuroendocrine markers, and autonomic cardiovascular responses associated with CFS in childhood cancer survivors. METHODS: Long-term survivors of childhood lymphoma and acute lymphoblastic leukemia reporting CF were compared with survivors without CF. Data included patient-reported outcomes, clinical examination, head-up tilt test, and neuroendocrine markers in the blood and the urine. RESULTS: Of 102 included survivors, 15 were excluded from comparative analyses because of significant co-morbidity or pregnancy. Of the remaining 87 participants (median age 33.0 years, follow-up time 25.2 years), 35 had CF and 52 did not have CF. Compared with non-CF controls, CF cases reported a significantly (P < 0.01) higher frequency of symptoms typical of the CFS (muscle or joint pain or both and feeling confused/disoriented) and symptoms of autonomic dysfunction (palpitations, feeling intermittently heat and cold, and watery diarrhea). CF cases and controls did not differ regarding autonomic cardiovascular responses to orthostatic stress, but the CF group had lower levels of plasma adrenocorticotrophic hormone (P = 0.002) and higher levels of urine norepinephrine (P = 0.017). CONCLUSIONS: Survivors with CF reported a high symptom-burden compared with controls. There were few differences between both the groups regarding biomarkers, but slight alterations of the hypothalamus-pituitary-adrenal axis and sympathetic nervous activity were detected. CF in cancer survivors has features in common with the CFS, but further efforts are required to clarify the pathophysiology.

High density lipoprotein as a source of cholesterol for adrenal steroidogenesis: a study in individuals with low plasma HDL-C.

Few studies have addressed the delivery of lipoprotein-derived cholesterol to the adrenals for steroid production in humans. While there is evidence against a role for low-density lipoprotein (LDL), it is unresolved whether high density lipoprotein (HDL) contributes to adrenal steroidogenesis. To study this, steroid hormone profiles in urine were assessed in male subjects suffering from functional mutations in ATP binding cassette transporter A1 (ABCA1) (n = 24), lecithin:cholesterol acyltransferase (LCAT) (n = 40), as well as in 11 subjects with low HDL cholesterol (HDL-C) without ABCA1/LCAT mutations. HDL-C levels were 39% lower in the ABCA1, LCAT, and low HDL-C groups compared with controls (all P < 0.001). In all groups with low HDL-C levels, urinary excretion of 17-ketogenic steroids was reduced by 33%, 27%, and 32% compared with controls (all P < 0.04). In seven carriers of either type of mutation, adrenocorticotropic hormone (ACTH) stimulation did not reveal differences from normolipidemic controls. In conclusion, this study shows that basal but not stimulated corticosteroid metabolism is attenuated in subjects with low HDL-C, irrespective of its molecular origin. These findings lend support to a role for HDL as a cholesterol donor for basal adrenal steroidogenesis in humans.

Coexistence of Cushing syndrome from functional adrenal adenoma and Addison disease from immune-mediated adrenalitis.

A 56-year-old woman presented with an incidental adrenal adenoma and physical examination findings that included moderate obesity, a slight cervicothoracic fat pad ("buffalo hump"), increased supraclavicular fat pads, and white abdominal striae. Biochemical workup revealed elevated levels of 24-hour urinary free cortisol but normal serum morning cortisol and suppressed levels of corticotropin, suggestive of adrenal-dependent Cushing syndrome. The resected adrenal gland revealed macronodular cortical hyperplasia with a dominant nodule. Other findings included an absent cortisol response to corticotropin stimulation, presence of serum anti-21-hydroxylase antibodies, and mononuclear cell infiltration--consistent with adrenalitis. The findings represent, to the authors' knowledge, the first known case of a patient with coexistent functional cortisol-secreting macronodular adrenal tumor resulting in Cushing syndrome and immune-mediated adrenalitis resulting in Addison disease.

Cushing's syndrome associated with a nested stromal epithelial tumor of the liver: hormonal, immunohistochemical, and molecular studies.

CONTEXT: Ectopic ACTH syndrome (EAS) is principally associated with aggressive malignant tumors but also with neuroendocrine tumors of good prognosis. Recently, rare nonhepatocytic nested stromal and epithelial tumors (NSET) were characterized by their possible association with Cushing's syndrome of which biochemical and physiopathological features were still incompletely studied. OBJECTIVE: To describe the clinical and hormonal characteristics of an EAS originating from a liver NSET and further understand the mechanism of cortisol overproduction. DESIGN AND SETTING: This is a clinical case report from the Endocrinology Department of Caen University Hospital, France. PATIENT AND INTERVENTION: A 17-year-old female patient was found to have a large liver NSET with mild Cushingoid clinical features and intense biological hypercortisolism but moderate ACTH secretion. Resection of the tumor was curative with a 30-month follow-up. RESULTS: The epithelial component of the tumor coexpressed ACTH mildly, corticotropin-releasing hormone (CRH) strongly, and 11beta-hydroxysteroid dehydrogenase at a level comparable with normal human hepatocytes. CONCLUSIONS: Liver NSET is a new cause of EAS, which may evoke hypercortisolism by multiple biochemical pathways.

Determination of Synacthen in urine for sports drug testing by means of nano-ultra-performance liquid chromatography/tandem mass spectrometry.

Doping control analysis of performance-enhancing peptides in urine represents a challenging requirement in modern sports drug testing. Low dosing, effective metabolism and short half-life lead to target concentrations in the low fmol/mL range in urine. Synthetic adrenocorticotropic hormone (1-24, Syn-ACTH-en) shares all these characteristics and improved analytical performance is required for its sufficient determination by means of liquid chromatography/tandem mass spectrometry (LC/MS/MS). The desired effects for cheating sportsmen are mainly due to enhanced release of corticosteroids as well as androgenic steroids into the circulation after systemic administration of the drug. Immunoaffinity purification with coated magnetic beads and subsequent liquid chromatography with nano-ultra-performance liquid chromatography (UPLC) coupled to tandem mass spectrometry (high resolution/high mass accuracy) of Synacthen from urinary specimens is described in the present study. The general proof of principle was obtained by analysis of excretion study urine samples and validation was performed with focus on the limit of detection (3 pg/mL), linearity, precision (<20%), recovery ( approximately 30%), robustness, specificity and stability. For all experiments, the ACTH fragment 1-17 was used as the internal standard.

Ectopic ACTH syndrome caused by pheochromocytoma: computed tomography-guided percutaneous ethanol injection as an alternative treatment.

Ectopic ACTH secretion represents 8-18% of the cases of endogenous hypercortisolism. Pheochromocytomas correspond to 2-25% of the cases and surgery is the indicated treatment. We describe a case of ACTH-secreting pheochromocytoma treated with percutaneous ethanol injection (PEI) guided by computed tomography (CT). A 71-yr-old man presented with diabetes, severe hypokalemia, weight loss, muscle weakness, and hypertension. Hormonal evaluation revealed elevated levels of urinary cortisol, ACTH, catecholamines, and urinary metanephrines. There was no cortisol or ACTH response to desmopressin stimulation test. Magnetic resonance revealed bilateral adrenal nodules, larger on the left side. The suspected diagnosis was ectopic ACTH syndrome caused by pheochromocytoma. Ketoconazole treatment resulted in reduction of urinary cortisol levels but was followed by severe cholestasis and hepatic dysfunction, preventing surgery; it was substituted by octreotide with reduction of ACTH and cortisol levels, but without improvement of cholestasis. The patient presented cachexia and developed multiple pulmonary abscesses that also prevented surgical treatment, thus he was treated with percutaneous ethanol injection guided by CT of the left adrenal tumor. During the procedure, the patient had an increase in blood pressure controlled by the infusion of sodium nitroprusside followed by hypotension that required infusion of dopamine and volume expansion. Afterwards, he presented hormonal normalization, normal catecholamines levels, and clinical improvement. Histological tissue analysis confirmed pheochromocytoma. We concluded that CT-guided PEI represents an efficient alternative therapy to ectopic ACTH-secreting pheochromocytomas in patients without clinical conditions for surgery.

[Analysis of early prognostic factors for risk of treatment failure in Cushing's disease treated by trans-sphenoidal pituitary surgery]. / Estudio de factores pronósticos precoces de riesgo de fallo del tratamiento en la enfermedad de Cushing tras la cirugía hipofisaria transesfenoidal.

BACKGROUND AND OBJECTIVE: We performed an analysis of early factors influencing the outcome of Cushing's disease treated by transsphenoidal pituitary surgery. PATIENTS AND METHOD: Prospective study of 29 patients who underwent transsphenoidal pituitary surgery for Cushing's disease. The prognostic value of preoperative and operative variables, histological findings and serum cortisol (measured at 8:00 a.m. the day after surgery) were analyzed. RESULTS: Of the 29 patients included in this study, 26 achieved postoperative remission while in 3 patients treatment failed. Tumor was identified at histology in 92.3% patients in the remission group and in 33.3% in the failure group, this difference being significant (p = 0.03). Median postoperative cortisol levels were 95.8 nmol/l in the remission group and 676 nmol/l in the failure group, this difference being significant (p = 0.024). Serum cortisol of 600 nmol/l correctly classified the remission and failure groups with a sensitivity of 100% and a specificity of 96%. CONCLUSIONS: In our experience, no identification of an adenoma at histology and an early postoperative cortisol level higher than 600 nmol/l after transsphenoidal pituitary surgery for Cushing's disease was associated with a high risk of failed treatment.

No effect of free fatty acids on adrenocorticotropin and cortisol secretion in healthy young men.

Free fatty acids (FFAs) affect anterior pituitary function. However, the effect of FFAs on corticotropin (ACTH) and cortisol in humans is controversial. Thus, we assessed the effect of a pronounced increase in circulating FFA levels induced by infusion of lipid/heparin on ACTH and cortisol secretion in young men. Eight healthy male volunteers who underwent a 10-hour overnight fast were investigated. A 20% lipid/heparin or saline/heparin infusion was given at a rate of 1.5 mL/min for 6 hours. A euglycemic hyperinsulinemic clamp was performed in 6 subjects 4 hours after the start of infusion. To assess steroid metabolism, we measured ACTH, cortisol, FFAs, and urinary steroids. Lipid infusion increased FFAs (6.06 +/- 0.52 vs 0.70 +/- 0.23 mmol/L; P < .005) and induced insulin resistance (glucose infusion rate, 4.08 +/- 2.15 vs 6.02 +/- 2.60 mg/kg per minute; P < .005). Serum cortisol and plasma ACTH decreased independent of lipid/heparin or saline/heparin infusion. In addition, we found no effect of hyperinsulinemia on ACTH and cortisol levels. There were no differences in urinary free cortisol, urinary free cortisone, 5beta-tetrahydrocortisol, 5alpha-tetrahydrocortisol, and tetrahydrocortisone. In conclusion, FFAs had no effect on basal ACTH and cortisol secretion in normal-weight young men. In addition, no alterations in urinary glucocorticoid metabolites were detected, suggesting unchanged cortisol metabolism during lipid infusion.

Progressive alterations in the hypothalamic-pituitary-adrenal axis in the R6/2 transgenic mouse model of Huntington's disease.

Huntington's disease (HD) is characterized by a triad of motor, psychiatric and cognitive symptoms. Although many of these symptoms are likely to be related to central nervous system pathology, others may be due to changes in peripheral tissues. The R6/2 mouse, a transgenic model of HD expressing exon 1 of the human HD gene, develops progressive alterations in the hypothalamic-pituitary-adrenal axis, reminiscent of a Cushing-like syndrome. We observed muscular atrophy, reduced bone mineral density, abdominal fat accumulation and insulin resistance in the mice. All these changes could be consequences of increased glucocorticoid levels. Indeed, hypertrophy of the adrenal cortex and a progressive increase in serum and urine corticosterone levels were found in R6/2 mice. In addition, the intermediate pituitary lobe was markedly enlarged and circulating adreno-corticotrophic hormone (ACTH) increased. Under normal conditions dopamine represses the ACTH expression. In the R6/2 mice, however, the expression of pituitary dopamine D2 receptors was reduced by half, possibly explaining the increase in ACTH. Urinary samples from 82 HD patients and 68 control subjects were analysed for cortisol: in accord with the observations in the R6/2 mice, urinary cortisol increased in parallel with disease progression. This progressive increase in cortisol may contribute to the clinical symptoms, such as muscular wasting, mood changes and some of the cognitive deficits that occur in HD.

In vivo activity of 11beta-hydroxysteroid dehydrogenase type 1 and free fatty acid-induced insulin resistance.

INTRODUCTION: Free fatty acids (FFAs) induce hepatic insulin resistance and enhance hepatic gluconeogenesis. Glucocorticoids (GCs) also stimulate hepatic gluconeogenesis. The aim of this study was to investigate whether the FFA-induced hepatic insulin resistance is mediated by increased activity of hepatic 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), accompanied by elevated hepatic cortisol levels. METHODS: Following a 10-h overnight fast, six healthy male volunteers were investigated. A euglycaemic hyperinsulinaemic clamp was performed during lipid or saline infusion. To assess hepatic 11beta-HSD1 activity, plasma cortisol levels were measured after oral administration of cortisone acetate during lipid or saline infusion. In addition, 11beta-HSD activities were determined in vivo by calculating the urinary ratios of GC metabolites. RESULTS: Lipid infusion increased FFAs (5.41 +/- 1.00 vs. 0.48 +/- 0.20 mmol/l; P < 0.005) and significantly increased insulin resistance [glucose infusion rate (GIR) 6.02 +/- 2.60 vs. 4.08 +/- 2.15 mg/kg/min; P < 0.005]. After lipid and saline infusions no changes in 11beta-HSD1 activity were found, neither by changes in cortisone acetate to cortisol conversion nor by differences in urinary free cortisol (UFF) or cortisone (UFE), 5beta-tetrahydrocortisol (THF), 5alpha-THF, cortisone (THE), UFF/UFE and (5alpha-THF + THF)/THE ratios. CONCLUSIONS: We found no change in hepatic and whole-body 11beta-HSD1 activity during acute FFA-induced insulin resistance. Further studies are necessary to clarify whether 11beta-HSD1 in muscle and adipose tissue is influenced by FFAs and whether 11beta-HSD1 is involved in other conditions of insulin resistance.

Dissection of hypothalamic-pituitary-adrenal axis pathology in 1-month-abstinent alcohol-dependent men, part 2: response to ovine corticotropin-releasing factor and naloxone.

BACKGROUND: Pituitary and adrenal responsiveness is suppressed in abstinent alcohol-dependent individuals. To clarify the specific organizational disruption in hypothalamic-pituitary-adrenal functioning during early abstinence, the authors separately assessed each level of the stress-response axis. In this second of a two-part study, ovine corticotropin-releasing factor (oCRH) was used to stimulate the pituitary corticotrophs, and naloxone was used to activate the axis at the hypothalamic level. In addition, pulsatile characteristics of corticotropin and cortisol were assessed over a 12-hr period (0800 to 2000 hr). METHODS: Eleven abstinent alcohol-dependent men and 10 healthy comparison participants were assessed. All participants were between the ages of 30 and 50 years, and alcohol-dependent patients were abstinent from 4 to 6 weeks. Basal concentrations of corticotropin and cortisol were obtained every 10 min from 0800 to 2000 hr and subjected to pulsatile analysis. Plasma corticotropin and cortisol concentrations were then obtained every 5 to 10 min after low-dose, intravenously administered doses of oCRH (0.4 microg/kg) or naloxone (0.125 mg/kg). Medications were administered at 2000 hr and the two challenge studies were separated by 48 hr. RESULTS: Pulsatile analysis revealed that the mean corticotropin amplitude was increased in alcohol-dependent patients relative to controls (p <0.05). Other pulsatile characteristics of corticotropin and all cortisol pulsatile measures were not significantly different between the two groups. The integrated cortisol response to oCRH was significantly lower in alcohol-dependent patients compared with controls (p <0.01), but the integrated corticotropin response was not significantly different. In contrast, neither the corticotropin nor the cortisol response to naloxone was significantly different between groups. CONCLUSIONS: Adrenocorticoid hyposensitivity persists after oCRH infusion for at least 1 month after cessation of drinking, whereas hyporesponsiveness of the pituitary corticotrophs to CRH seems to resolve with continued abstinence. The authors suggest that adrenocortical hyporesponsiveness during prolonged abstinence may impact relapse risk.

A non-invasive method for assessing adrenal activity in the chinchilla (Chinchilla lanigera).

The Chinchilla is a rodent that was once abundant in the central Andes of South America. Excessive hunting for fur greatly reduced its distribution at the beginning of the twentieth century, and today Chinchilla species are nearly extinct in the wild. Although protected, wild populations of chinchilla are still declining. In general, this species has received little research attention and its biology is poorly understood. Improvements in captive breeding, husbandry, and genetic management are needed to ensure the conservation of the species. In this study, a noninvasive corticosteroid hormone monitoring technique was validated for use in Chinchilla lanigera. Two male domestic chinchillas were administered 3H-corticosterone (i.m.) to determine the time course and relative proportion of urinary and fecal steroid metabolites. Most radioactivity was detected in urine and feces 5-10 and approximately 30 h post-isotope administration, respectively. Corticosteroid immunoreactivity was assessed by corticosterone radioimmunoassay (RIA) and cortisol enzyme immunoassay (EIA). High-pressure liquid chromatography (HPLC) separation of corticosteroid metabolites in unprocessed urine revealed the presence of highly polar corticosteroid metabolites, but after enzymatic hydrolysis and diethyl ether extraction, most immunoreactivity co-eluted with unconjugated cortisol. A 'cause-and-effect' relationship between the administration of exogenous adrenocorticotrophic hormone (ACTH), and the appearance of increased urinary corticosteroid metabolites demonstrated the physiological relevance of these measures for evaluating adrenal status in male chinchillas. From a conservation perspective, these methods can aid in situ and ex situ initiatives designed to evaluate how environmental conditions and management strategies affect overall animal health, well-being and reproduction.