Cushing's syndrome: a review of diagnostic tests

Clinical aspects of endocrine hypertension

Distinct hypertensive syndromes clearly related to overproduction of certain hormones are increasingly being recognized. The ability to recognize these disorders has come as a result of better understanding of their pathophysiology and the availability of sensitive and accurate diagnostic tools. The particular appeal of making the diagnosis centers around the potential curability of the hypertension with correction of the hormonal abnormality.

Diagnosis and treatment of functioning and nonfunctioning adrenocortical neoplasms including incidentalomas

The most important functional tumors of the adrenal cortex are those that secrete cortisol or aldosterone in excess. Biochemical testing when appropriately utilized can diagnose and differentiate the cause of Cushing's syndrome, and when an adrenal adenoma is found, surgical excision is curative. The diagnosis and surgical treatment of primary aldosteronism are straightforward today, and localization of the usual small cortical tumor producing the syndrome can be achieved by CT and NP-59 scanning or selective venous assays. Adrenocortical carcinomas are relatively rare, are usually incurable when diagnosed, and are an important consideration in the incidentally discovered adrenal mass found by CT scanning.

Alcohol-induced pseudo-Cushing's syndrome mimicking Cushing's disease in a patient with an adrenal mass

Alcohol-induced pseudo-Cushing's syndrome is a disorder in which patients exhibit clinical and/or biochemical features similar to those in patients with Cushing's syndrome, but these features, related to alcohol abuse, may be transient and resolve during abstinence from alcohol. In most previous reports of alcohol-induced pseudo-Cushing's syndrome, detailed endocrinologic data supporting a diagnosis of Cushing's syndrome have been lacking. This report describes a patient with clinical features of Cushing's syndrome, increased plasma ACTH values, and elevated levels of basal urinary free cortisol and 17-hydroxysteroids that were not suppressed by low-dose dexamethasone but were suppressed by high-dose dexamethasone. Detailed test results were indistinguishable from those in Cushing's disease, which had been the initial diagnosis. When an occult history of alcohol abuse was discovered, the suspicion of alcohol-induced pseudo-Cushing's syndrome was raised. During an extended hospitalization and abstinence from alcohol, abnormal endocrinologic test results gradually became normal. This patient also demonstrated a further complicating feature, a left adrenal mass, which appeared to be a benign, coincidental lesion. Because of the high prevalence of alcohol abuse and the possibility that test results may be identical to those in Cushing's disease, clinicians should be familiar with this disorder to avoid misdiagnosis and inappropriate therapy.

Cushing's syndrome due to ectopic proopiomelanocortin gene expression by islet cell carcinoma of the pancreas

Expression of proopiomelanocortin (POMC) was studied in a male patient with Cushing's syndrome and ectopic production of ACTH by a pancreatic carcinoma. Plasma ACTH levels (greater than 200 pg/ml) were elevated, and elevated serum cortisol and urinary free cortisol were partially suppressed to 25% of basal levels by high-dose dexamethasone. Petrosal and jugular vein sampling did not yield a gradient of ACTH. Immunohistochemical staining of tumor tissue removed at pancreatectomy was positive for ACTH and beta endorphin, and negative for corticotropin-releasing factor (CRF). Tumor cells cultured in vitro secreted ACTH and beta-endorphin, which comigrated with their respective radiolabeled standards on gel chromatography. Hydrocortisone suppressed in vitro ACTH secretion and CRF (100 nM) stimulated ACTH by 50% during 72 hours of incubation. Agarose gel electrophoresis of poly-(A) mRNA extracts of tumor tissue followed by hybridization with 32P-cDNA for POMC revealed 2 distinct RNA species. The major RNA species (about 1.0 kb) was smaller than authentic pituitary POMC mRNA (about 1.1 kb); a larger precursor band also was visualized, suggesting either processing or degradation of tumor-POMC mRNA. Cytoplasmic dot blot hybridization of tumor mRNA with POMC cDNA yielded a positive signal with increasing amounts of RNA blotted. Immunohistochemistry and radioimmunoassay (RIA) of ACTH, in vitro regulation of ACTH secretion, and expression of POMC mRNA species by this tumor document expression of the human POMC gene by an islet carcinoma associated with Cushing's syndrome.

The interrelationship of beta endorphin, ACTH and cortisol in depressive illness: a controlled study

Plasma cortisol, ACTH and beta endorphin were measured before and after dexamethasone in 8 severely depressed patients and 8 age- and sex-matched controls to examine the relationship of ACTH and endogenous opioids to cortisol in depression. Despite having significantly higher plasma levels of cortisol than the controls, the depressed patients did not have correspondingly elevated plasma levels of ACTH. Beta-endorphin levels were also similar in the two groups. All three hormones suppressed to some degree after dexamethasone, but cortisol suppressed less in patients than controls. Our findings suggest that in severe depressive illness abnormalities exist in the hypothalamic-pituitary-adrenal axis peripherally as well as centrally.

An evaluation of clinicians' subjective prior probability estimates

The degree of consensus and the accuracy of subjective prior probability estimates made by 104 clinicians were examined. The clinicians' estimates were compared with objective prior probabilities obtained from published sources and actual patient outcomes. Each clinician made seven estimates based upon written case summaries abstracted from patient records. Consensus was measured by calculating estimate ranges and standard deviations. The clinicians' estimates varied widely: the smallest range was 80 (2%-82%); four of the seven probability ranges were greater than 90. The average standard deviation was 19.5. Using these prior probabilities and Bayes' theorem, widely varying posttest probabilities would result after many common diagnostic tests. Accuracy was measured using the Brier score, which ranges from 0 to 1; a score of 0 indicates perfect accuracy. The clinicians' Brier scores ranged from 0.05 to 0.57. The objectively determined probabilities achieved a Brier score of 0.11, better than that of 96% of the clinicians. Clinical experience did not consistently affect estimate accuracy or consensus. The clinicians' subjective estimates were inaccurate measures of the prior probability of disease. There was little consensus regarding disease likelihood among the clinicians. Objective prior probabilities were more accurate and less variable.

The corticotropin-releasing-hormone test versus the high-dose dexamethasone test in the differential diagnosis of Cushing's syndrome

The diagnostic accuracy of the corticotropin-releasing-hormone (CRH) test was compared with that of the oral high-dose dexamethasone suppression test in the differential diagnosis of Cushing's syndrome. A false-negative response to CRH was present in 9% (2 of 22) of patients with pituitary-dependent Cushing's disease and to high-dose dexamethasone in 11% (2 of 18). All 3 patients with Cushing's syndrome due to an adrenal adenoma were unresponsive to both CRH and dexamethasone. The only patient with ectopic corticotropin secretion had a false-positive response of corticotropin to dexamethasone and no response of corticotropin to CRH. Simultaneous failure of both tests to indicate the cause of Cushing's syndrome did not occur in this series, except in 1 patient with Cushing's disease and overt macronodular hyperplasia. It is concluded that the diagnostic accuracy of the CRH test in patients with Cushing's syndrome is comparable to that of the high-dose dexamethasone test and that the highest discriminatory score in the differential diagnosis of Cushing's syndrome is achieved by using both a CRH test and a high-dose dexamethasone test.

Cushing's syndrome in patients with the Zollinger-Ellison syndrome

Reports of Cushing's syndrome in patients with the Zollinger-Ellison syndrome are rare, although up to 30 percent of gastrinomas contain ACTH-like immunoreactivity. We prospectively examined 75 patients with the Zollinger-Ellison syndrome for Cushing's syndrome. Three of 59 patients (5 percent) with the sporadic form of the Zollinger-Ellison syndrome had Cushing's syndrome, with severe symptoms due to ectopic production of ACTH. Each of these patients had metastatic gastrinoma, responded poorly to chemotherapy, and died within three years of the diagnosis of both syndromes. Three of 16 patients (19 percent) with the Zollinger-Ellison syndrome and multiple endocrine neoplasia type 1 had Cushing's syndrome due to pituitary production of ACTH, and their symptoms were mild. The gastrinoma in these patients was localized, and the prognosis was excellent. Thus, Cushing's syndrome is more common in patients with the Zollinger-Ellison syndrome than was previously reported, occurring in 8 percent of all cases. Furthermore, Cushing's syndrome in patients with sporadic Zollinger-Ellison syndrome and in those with multiple endocrine neoplasia type 1 differ in incidence, cause, clinical severity, extent of gastrinoma, the need for therapy, and prognosis. All patients with the Zollinger-Ellison syndrome and all patients with multiple endocrine neoplasia type 1 should be screened for Cushing's syndrome.

Secondary hypertension. A streamlined approach to diagnosis

Among the many potential causes of secondary hypertension are renal parenchymal disease, occlusive renal arterial disease, adrenocortical abnormalities, and pheochromocytoma. Renovascular hypertension can result from either renal parenchymal or occlusive renal arterial disease. Laboratory testing can help in identification and differentiation. Parenchymal diseases usually modify the urine substantially without producing urographic abnormalities, while occlusive arterial lesions produce urographic abnormalities but the urine remains normal. The diagnosis of renal occlusive arterial disease is best defined by arteriography. The only definite criterion for the existence of hypertension of renal origin is cure by either nephrectomy or renal revascularization. Adrenocortical causes of hypertension include enzymatic deficiencies, Cushing's syndrome, and primary aldosteronism. In enzymatic deficiencies, the physical findings provide the most important clues to the type of enzyme deficiency involved. In Cushing's syndrome, accurate determination of the cause of the hypercortisolism is important in terms of choice and success of treatment. The diagnosis of primary aldosteronism rests primarily on the demonstration of nonsuppressible aldosterone excretion rate during salt loading; the presence of inappropriate kaliuresis and/or suppressed plasma renin activity provides corroborative evidence of primary aldosteronism, but the absence of either or both does not preclude the diagnosis. Pheochromocytoma, although rare, is a serious and potentially fatal cause of hypertension. Definitive diagnosis depends on laboratory test results, and the tumor is usually localized by computed tomography.

Diagnosis and management of ACTH-dependent Cushing's syndrome: comparison of the features in ectopic and pituitary ACTH production

The clinical features, diagnosis and management of 16 consecutive patients with ectopic ACTH production are described and biochemical data are compared with those of 48 consecutive patients with pituitary-dependent Cushing's disease. In 10 cases the ectopic ACTH secreting tumour was completely occult to routine clinical and radiological investigation, and no basal or dynamic investigation of adrenal-pituitary function was able clearly to differentiate these patients from those with Cushing's disease. High dose dexamethasone suppression testing assessed by plasma cortisol was usually helpful but unexpected responses were seen in both diagnostic groups; the metyrapone test yielded no useful information and should now be abandoned. Hypokalaemia was seen in all patients with ectopic ACTH production but in only 10% of those with Cushing's disease who were not on diuretics at presentation. Successful diagnosis and tumour localization was most frequently achieved by a combination of CT scanning of the chest and abdomen and venous catheter sampling for ACTH. All patients in whom the ectopic ACTH-secreting tumour was obvious at presentation died of their primary tumour within 8 months, whereas seven of the 10 patients with occult tumours at presentation are alive 1.5-16.5 years later, and appear cured. Occult ectopic ACTH secretion may be impossible to distinguish from pituitary Cushing's disease. Multiple and repeated investigations are often required to make this differential diagnosis, essential for appropriate therapy.

Evidence for a delayed, integral, and proportional phase of glucocorticoid feedback on ACTH secretion in normal human volunteers

To investigate the mechanisms responsible for glucocorticoid feedback on nonstress-induced ACTH secretion in normal subjects, 24 volunteer subjects (14 males and 10 females, 21 to 43 years) were divided into six groups in a randomized fashion and studied. Each subject received a single midnight dose of 30 mg/kg per body weight of metyrapone and then cortisol was administered according to different protocols in the next morning to provide extreme variations of the input signal. It was found that no obvious inhibition in plasma ACTH levels was shown during the first 15 min despite the fact that cortisol was given at rather larger doses and short time intervals. However, a significant suppression in plasma ACTH levels began to manifest approximately 30 min after cortisol administration in each study group and it became apparent that the degree of inhibition of ACTH level at 75 min correlated with the plasma cortisol concentrations at the same moment (r = 0.97, P less than 0.01) as well as with the dosage of cortisol during this time, whatever administered (r = 0.99, P less than 0.01). In summary, our data provided evidence for a delayed, proportional, and integral phase of glucocorticoid feedback on nonstress-induced ACTH secretion in normal human volunteers.

Cushing's disease with intermittent hypercortisolism

In a patient with proved pituitary-dependent Cushing's syndrome (Cushing's disease), 24-hour urinary excretion of free cortisol fluctuated between normal (69 percent of the time, often in the low range and for several days in sequence) and high values. Increased urinary free cortisol excretion occurred unpredictably within the context of a persistent, progressive clinical picture. This case stands in contrast with previous reports of urinary steroid levels varying in a periodic infradiem pattern. Even with normal baseline cortisol indexes, control of the hypothalamic-pituitary axis (as indicated by the suppression test and by the circadian cortisol pattern in plasma) remained abnormal. This patient emphasizes the fact that abnormal control regulation, more than cortisol hypersecretion, is at times indicative of Cushing's disease. Hence, sensitive accurate screening requires not only urinary free cortisol measurement (the usefulness of which may be improved by assay of more than one, possibly nonsequential, 24-hour urine sample), but also dexamethasone suppression testing and late-evening plasma cortisol determination, even if baseline indexes are within the range of normal.

Diagnosis and treatment of depression in the medically ill

The evaluation of depression in the medically ill is a complex task that requires considerable clinical skills. Physical illness is a common cause of psychopathology and this should alert the physician to search for possible organic explanations of depressive symptoms, especially in the elderly. Major depressive disorders need to be differentiated from physiological demoralizations secondary to the strains of somatic disturbances. Clinical guidelines for the use of antidepressant medications in the medically ill are provided.

Five cases of cyclical Cushing's syndrome

Reported cases of cyclical Cushing's syndrome are rare. Of 14 successive patients with Cushing's syndrome nine collected sequential urine samples for the estimation of cortisol:creatinine ratio. Five had cyclical Cushing's syndrome while two had considerable variation in urinary cortisol excretion without a cyclical pattern being established. Two of the five patients with a cyclical syndrome had paradoxical responses to dexamethasone. In only one patient with a cyclical pattern did the cortisol:creatinine ratio fall after treatment with bromocriptine or cyproheptadine, or both. The high incidence of the cyclical form of Cushing's syndrome has important clinical implications. A high index of suspicion of the syndrome is required in patients with symptoms or signs of Cushing's syndrome but with normal cortisol values, in patients with fluctuating cortisol values, and in patients with anomalous responses to dexamethasone. Because of possible variations in steroidogenesis the results of drug studies in Cushing's syndrome must be interpreted cautiously.

Cushing's syndrome

Cushing's syndrome remains one of the most challenging problems in clinical endocrinology. Cushing's disease is caused in the majority of cases by basophil pituitary microadenomas which may be successfully treated by trans-sphenoidal hypophysectomy. Treatment with metyrapone or o,p'-DDD can always induce a clinical remission but not a cure, and neurotransmitter therapy may be effective in a minority of cases. Pituitary irradiation cures about half of cases in the long-term and may be used for surgical failures. Tumours producing ectopic ACTH are frequently benign, small and occult and may produce a syndrome clinically indistinguishable from Cushing's disease. Biochemical investigations cannot absolutely distinguish pituitary from ectopic sources of ACTH and therefore body CT scanning and percatheter venous sampling are essential diagnostic investigations. Tumour localization may result in resection and complete cure, although even small tumours may have a malignant potential. Adrenal tumours are readily diagnosed by plasma ACTH measurement and adrenal CT scanning. Adrenal adenomas are cured by adrenalectomy. Carcinomas may be treated by a combination of adrenalectomy, radiotherapy and o,p'-DDD, but long-term prognosis is poor.

Evidence for ectopic ACTH production years after bilateral adrenalectomy for Cushing's syndrome: in vivo and in vitro studies

Three patients presented with hyperpigmentation and high plasma levels of ACTH 4-5 years after bilateral adrenalectomy for Cushing's "disease". X-rays and ct-scan of the lungs showed a small pulmonary mass in all. ACTH levels (1100-2000 pg/ml) were not suppressible by high doses hydrocortisone. A carcinoid tumor was removed in two cases and a chemodectoma in the third. Evidence for ACTH secretion by these tumors was provided by both decrease of ACTH levels after surgery and/or in vitro studies. Both carcinoid cultures showed a basal ACTH production, which was clearly increased by LVP (10(-7) M) and CRF (10(-7) M). Our findings in vitro studies suggest the presence of specific receptor sites for physiological stimuli (LVP and CRF) in tumor cell membranes.

Restoration of dexamethasone suppression by incomplete adenomectomy in Cushing's disease

Two cases of pituitary-dependent Cushing's disease are described. Selective transphenoidal adenomectomy was attempted in each, but proved incomplete. Although both patients had persistent Cushing's disease after the operation, both were shown to have been rendered fully dexamethasone suppressible. The pathophysiological basis of partial suppressibility is discussed, as are the criteria for the diagnosis of cure in Cushing's disease treated by selective adenomectomy.

Determination of urinary cortisol and 6 beta-hydroxycortisol by high performance liquid chromatography

A method using high performance liquid chromatography for the quantitative determination of cortisol and 6 beta-hydroxycortisol in urine is described. Urine extracts were fractionated by high performance liquid chromatography. The peak of 6 beta-hydroxycortisol was identified on the basis of retention time (24.4 min) and its area was measured. The peak of cortisol could not be measured simultaneously with the same column because of interference by other absorbing materials. The cortisol and dexamethasone peaks were collected (Rt values 9.6 and 8.1 min, respectively), rechromatographed on another column system, and the concentration was determined. Precision and accuracy of the present method were within the range commonly achieved by other methods established for both steroids. Clinical utility of the present method was evaluated by measuring urinary cortisol and 6 beta-hydroxycortisol in normal subjects, in Cushing's syndrome and disease patients, and in patients receiving cortisol therapy.

Adrenocortical carcinoma with Cushing's syndrome presenting unusual urinary 17-ketosteroid fractionation

A case of adrenal carcinoma with Cushing's syndrome was presented. Endocrinological and morphological investigations disclosed the presence of a functional adrenal carcinoma. This case was characterized by its unusual urinary 17-ketosteroid (17-KS) fractionation, i.e. a marked elevation of 17-KS was accompanied by the increments of etiocholanolone, but not of dehydroepiandrosterone (DHEA) or androsterone. Measurements of the plasma adrenocorticosteroids revealed normal DHEA and DHEA-S (sulfate) levels, moderately increased 17-OH-pregnenolone, and markedly increased (less than 100 times the normal) 11-deoxycortisol (cpd S). Therefore, it seems plausible that the normal urinary DHEA level in this patient would have occurred as a result of remarkably low C17-20 lyase activity sufficient to hamper DHEA production, and that markedly increased etiocholanolone might possibly have been converted from cpd S as well as from DHEA and androstenedione through 5 beta-reduction.

A direct radioimmunoassay for the determination of adrenocorticotropic hormone (ACTH) and a clinical evaluation

A direct radioimmunoassay for the determination of ACTH in a small volume of serum was developed using a commercially available antiserum and tracer. A single-stage radioimmunoassay with an incubation period of 4 days gave reliable and reproducible ACTH values. In the incubation medium 0.1% 2-mercaptoethanol was used as the antioxidant. During a 15-month period the assay has been used routinely in the laboratory. The coefficient of variation was less than 10% in the physiological and pathological range. A normal range of 12 to 60 ng/L was found. The reliability of the assay is demonstrated by results obtained in patients with disorders of the pituitary-adrenal axis.

Agoraphobia and the dexamethasone suppression test: atypical depression?

The tricyclic antidepressants and the monoamine oxidase inhibitors have been shown to be effective in the treatment of some patients with phobic and panic disorders. To explain this action it has been suggested that a number of these patients may have an atypical biological depression. In an attempt to test this hypothesis we used the dexamethasone suppression test (DST), which has been proposed as a state dependent biological marker of depression. We compared the non-suppression rate of agoraphobic patients suffering panic attacks with controls and with patients suffering major depression. Twenty-nine per cent of the agoraphobics showed non-suppression compared with 12% of the control group and 64% of the depressives.

Serum cortisol concentrations during low dose dexamethasone suppression test to screen for Cushing's syndrome

Forty four subjects (23 obese controls, 11 patients with possible Cushing's syndrome, and 10 patients with definite Cushing's syndrome) underwent low dose (0 X 5 mg every six hours for two days) dexamethasone suppression tests during which serum cortisol concentration at 0800 and excretion of urinary free cortisol over 24 hours were measured. Serum cortisol concentration fell to below 60 nmol/1 (2 X 2 micrograms/100 ml) in 31 subjects and remained above 250 nmol/1 (9 X 1 micrograms/100 ml) in the 13 others. Excretion of urinary free cortisol showed a similar response, falling to below 110 nmol (40 micrograms)/24 h in 31 and remaining above 180 nmol (65 micrograms)/24 h in the 13 others. There was complete concordance between the two variables in terms of the pattern of response. Serum cortisol concentration fell to below 60 nmol/1 (2 X 2 micrograms/100 ml) in at least 97% (31 of a possible 32) of subjects without Cushing's syndrome. On the other hand, a serum cortisol concentration of above 250 nmol/1 (9 X 1 micrograms/100 ml) after low dose dexamethasone gave a false positive diagnosis of Cushing's syndrome in at most only one of 13 patients (7 X 7%). Measurement of serum cortisol concentration during the low dose dexamethasone test is simpler than, and as accurate and reliable as, measurements of urinary steroids.

The elucidation of adrenal-cortical status by measuring two-hour urinary-free cortisol levels

Urinary-free cortisol (UFC) measured in 24-h samples has provided unambiguous data regarding adrenal-cortical status, but collection is cumbersome and compliance is a problem. We reasoned that measuring UFC in 2-h samples collected at strategic times would distinguish patients with adrenal-cortical disorders from normal subjects. Patients with Cushing's syndrome demonstrated late P.M. (samples collected between 2000 and 2400 h) 2-h UFC levels that were greater than or equal to 12.0 micrograms/2 h (reference interval for this time period is 0.1-3.2 micrograms/2 h, n = 35). Several patients with various symptoms of Cushing's syndrome displayed late P.M. levels within the reference interval. Those with adrenal insufficiency had morning (collected between 0500 and 0900 h) levels less than or equal to 0.2 microgram/2 h (reference interval 1.7-21.2 micrograms/2 h, n = 37). These data indicate that adrenal-cortical status is reflected by measuring UFC levels in 2-h samples.

In vitro secretion of pro-opiomelanocortin (POMC) derived peptides in human ACTH-producing pituitary adenomas: evaluation of hormone ratios in different functional states

In 14 cases of ACTH-producing pituitary adenomas (8 cases of Cushing's disease and 6 cases of Nelson's syndrome) dispersed cells prepared from adenoma tissue were incubated in a superfusion or static incubation system and investigated for ACTH, beta-endorphin (beta-EP) and beta-lipoprotein (beta-LPH) production. Effects of cortisol and lysine vasopressin (LVP) were evaluated. During the superfusion a qualitatively parallel secretory pattern is obtained for all hormones. Quantitatively, however, the response to LVP stimulation is more pronounced for beta-endorphin-like immunoreactivity (beta-LPH/beta-EP-IR) causing ACTH/beta-LPH/beta-EP-IR ratios to change throughout single experiments. beta-EP/beta-LPH ratios, however, which were estimated by means of Sephadex G-50 gel chromatography at various key points of the superfusion, were constant for each tumor, although variable between different adenomas, ranging from 0.68 to 2.0. The results suggest neither a differential control for the secretion of the peptides investigated within individual tumors nor a direct effect of cortisol or LVP on pro-opiomelanocortin processing. Summarizing clinical data and in vitro findings such as secretory behavior or hormone ratios, we can find no characteristic differences between Nelson's syndrome and Cushing's disease.

[Dexamethasone suppression test: a biologic marker of endogenous depression?]

In the past few years there have been numerous publications, which have stressed the value of the Dexamethasone Suppression Test (DST) as a diagnostic marker of endogenous depression. Our own studies in 333 psychiatric inpatients and 121 healthy subjects did not reveal a differential diagnostic use for the DST. This result is in good agreement with recent results published in the literature. Our own data demonstrate, however, that intervening variables, such as severity of illness, weight loss, sleep disturbances, situational stress, drug and alcohol withdrawal and the pharmacokinetics of dexamethasone, have an important influence on the DST results, regardless of the diagnostic classification.

Evaluation of sympathoadrenal activity, adrenocortical function and androgenic status in five men during a Himalayan mountaineering expedition (ascent of Mt Pabil, 7,102 m, 23,294 ft)

Sympathoadrenal activity, adrenocortical function and androgenic status were studied in five well-trained mountaineers during the different phases of a mountaineering expedition during the ascent of Mt Pabil (7,102 m) in the Ganesh Himal massif. Sympathoadrenal activity was evaluated by measuring urinary excretion of adrenaline, noradrenaline, metanephrines, and vanillinmandelic acid. Adrenocortical function was assessed by measuring urinary excretion of free cortisol, 17 OHCS (17-hydroxycorticosteroids) and androgenic status by measuring testosterone glucuronide, Adiol (5 alpha-androstane-3 alpha, 17 beta diol) and 17KS (17-ketosteroids). Reference values were obtained at Chamonix at 1,037 m during rest. During trekking noradrenaline increased significantly while Adiol and 17-KS decreased. The fall in the urinary androgenic pool persisted during the next phases of the expedition. At base camp (4,800 m) noradrenaline, its metabolites and free cortisol increased mainly during physical activity. Above 6,000 m, adrenaline, noradrenaline, their metabolites, free cortisol and 17-OHCS reached a maximum value. During the return to sea level, the urinary level of these parameters was still high. The drop in the urinary androgenic pool observed during trekking and exposure to high altitude confirms results obtained in other studies on prolonged efforts. This hypoandrogenicity may play an important role in the metabolic adaptations as well as in the mental state of the climbers. The increase of sympathoadrenal activity and of adrenocortical function may be considered as a regulatory element in the adaptative response to hypoxia and other stressors proper to high altitude.

Investigation of hypothalamic-pituitary disease

It can be readily appreciated from the preceding discussion that many endocrine and non-endocrine tests are available for the evaluation of patients with suspected hypothalamic-pituitary disease. The endocrine evaluation of these subjects should be tailored according to the type and extent of pathology suspected (see Tables 2 and 3). For patients with pituitary adenomas and clinical features of hyperpituitarism, such as hyperprolactinaemia, Cushing's disease or acromegaly, the initial tests should be directed at the hormone whose excess is suspected. For example, a glucose suppression test for acromegaly or dexamethasone suppression test for Cushing's disease should be performed early in the evaluation. The possibility of deficiencies of the other pituitary hormones should then be addressed in patients with secretory tumours, but initially in those with apparent non-functioning adenomas. In patients with large macroadenomas pituitary hormone deficiencies are almost invariable with GH and FSH/LH being the most commonly affected, followed by TSH and ACTH in that order (Snyder et al, 1979a; Valenta et al, 1982). Basal thyroid function tests, serum oestradiol or testosterone, and basal gonodotrophins should be routinely obtained in patients with macroadenomas. Additionally, the integrity of the pituitary-adrenal axis should be determined and an overnight water deprivation test for assessment of neurohypophyseal function is also recommended. GH stimulation testing is valuable as a test of pituitary function in patients with suspected pituitary tumours since GH reserve is lost very early in the development of hypopituitarism. Evaluation of the pituitary-thyroid axis with TRH or the pituitary gonadal axis with LHRH generally provides limited additional information of diagnostic value in individual patients with macroadenomas. However, the 'paradoxical' responses to TRH and LHRH may be useful as a biological marker following therapy in patients with GH- or ACTH-secreting tumours. In patients with microadenomas, pituitary hormone deficiencies are uncommon (Valenta et al, 1982). Despite this observation, it may be beneficial to determine basal thyroid levels, gonadotrophin levels, serum testosterone or oestradiol levels, and the response to an overnight metyrapone test in such patients to provide a baseline for future care.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal cortical function in homozygous familial hypercholesterolemia

The biosynthesis of adrenal corticosteroids requires a supply of cholesterol that can be derived from both local synthesis and uptake of plasma lipoproteins. Recent studies have provided evidence that receptor-mediated uptake of low density lipoproteins provides an important source of cholesterol for corticosteroid synthesis by human adrenocortical cells that are grown in tissue culture. In the present study we have examined parameters of adrenocortical function in three patients with homozygous familial hypercholesterolemia (two receptor negative, one receptor defective) to assess whether a decreased number of LDL receptors, measured in vitro, influences in vivo corticosteroid production under basal conditions and in response to prolonged stimulation with ACTH. Basal adrenocortical function (assessed by the serum concentrations of cortisol and ACTH plus urinary excretion of 17 OHCS, 17 KS, and urine-free cortisol) was normal in all three patients. Stimulation with intravenous ACTH resulted in rapid increases in the serum concentrations of cortisol in all patients. Plateau concentrations of cortisol during prolonged ACTH stimulation were lower in the two receptor-negative patients (36 to 41 micrograms/dl) but all subjects had at least a threefold increase over basal values. Excretion of urine-free cortisol was reduced in both receptor-negative patients (33% to 36% of controls); this was paralleled by decreased excretion of 17 KS in both patients and of 17 OHCS in one patient. Urine-free cortisol excretion was reduced in the receptor-defective patient (57% of controls), but excretion of 17 OHCS and 17 KS was not.(ABSTRACT TRUNCATED AT 250 WORDS)

Human salivary eicosanoids: circadian variation

A circadian rhythm in the concentrations of prostaglandins (PG) E2, PGF2, PGI2 (measured as 6-keto-PGF1 alpha), immunoreactive h hydroxyeicosatetraenoic acids and immunoreactive 6-sulfidopeptide containing leukotrienes in human mixed saliva was observed. The rhythm reflected changes in the absolute amounts of these compounds in saliva. Under usual sleep-wake cycles a single peak occurred during sleep with maximal levels at 5:00 AM; the amplitude of the peak varied for each product. The rhythm was sleep-dependent and a shift occurred when the sleep-wake cycles were displaced. Basal levels of these eicosanoids were maintained even without sleep.

Ruder syndrome. Clinical and pathologic correlation

Ruder syndrome is an unusual varient of adrenal hyperfunction characterized clinically by debilitating osteopenia, and pathologically by bilateral micronodular adrenal hyperplasia. A unique case resembling Ruder syndrome is described in which the dominant pathologic feature was unilateral adrenal adenomatosis.

The superiority of the metyrapone test versus the high-dose dexamethasone test in the differential diagnosis of Cushing's syndrome

Differentiating the cause of Cushing's syndrome traditionally has depended upon measuring the response of 24-hour urine samples of cortisol or glucocorticoid metabolites to the high-dose (8 mg per day) dexamethasone test. The metyrapone test, however, is more convenient because it is a shorter test and requires the obtainment of serum samples, which can be collected more simply and more reliably than 24-hour urine samples. The usefulness of these two tests has not been adequately evaluated in a large series of patients with Cushing's syndrome. This study prospectively evaluated the accuracy of the dexamethasone and metyrapone tests in determining the cause of Cushing's syndrome in a series of 25 unselected patients. The diagnostic accuracy of these tests was calculated as follows: diagnostic accuracy = true positives and true negatives/study population X 100. Results of this study demonstrated that the metyrapone test was more accurate than the dexamethasone test in differentiating Cushing's disease from adrenocortical neoplasm (diagnostic accuracy, 100 percent versus 81 percent). All patients with Cushing's disease had a normal postmetyrapone 11-deoxycortisol concentration (greater than 10 micrograms/dl), while all patients with adrenocortical neoplasm had a suppressed 11-deoxycortisol concentration (less than 10 micrograms/dl). Thus, this study demonstrates that the metyrapone test is superior to the high-dose dexamethasone test in the differential diagnosis of Cushing's syndrome.

Suppression of cortisol secretion by low-dose dexamethasone testing in Cushing's disease. Case report

✓ Pituitary-adrenal function in a patient with classical features of Cushing's disease, increased urinary excretion of cortisol, and documented pituitary adenoma was found to be suppressed by dexamethasone in doses even less than those required to inhibit secretion in normal individuals. This response was shown to be due to inappropriately high levels of dexamethasone in plasma, presumed to be the consequence of decreased peripheral clearance. Because the dexamethasone suppression test is so widely used for diagnosis of Cushing's disease, it is important to recognize that this situation can occasionally occur.

Determination of urinary free cortisol and cortisone by sequential thin layer and high-performance liquid chromatography

A specific, rapid and sensitive method for urinary free cortisol and cortisone utilizing sequential thin layer (TLC) and high-performance liquid chromatography (HPLC) was developed. After addition of prednisone as the internal standard to 1 ml of urine, extraction of the steroids was accomplished by automated sorption on and desorption from a styrenedivinylbenzene copolymeric resin cartridge. Further purification was carried out by TLC. Quantitation of the recovered steroids at 254 nm was achieved during HPLC in a reverse phase system with 21-deoxycortisone as the external standard. When the values of urinary free cortisol both from normal subjects and patients were compared with those obtained by a current RIA procedure, the greater specificity of the new method was clearly demonstrated. Simultaneous measurement of both urinary free cortisol and cortisone in various clinical states appears to offer a more complete index of adrenocortical function than urinary free cortisol alone.