Carney complex, a familial multiple neoplasia and lentiginosis syndrome. Analysis of 11 kindreds and linkage to the short arm of chromosome 2.

Carney complex is an autosomal dominant syndrome characterized by multiple neoplasias, including myxomas at various sites and endocrine tumors, and lentiginosis. The genetic defect(s) responsible for the complex remain(s) unknown. We studied 101 subjects, including 51 affected members, from 11 North American kindreds with Carney complex. Blood samples were collected from patients and their family members. Hospital records, photographs, and tissue specimens of deceased individuals were reviewed. DNA was extracted from blood samples, patient-derived cell lines, and/or paraffin-embedded tissues. Linkage analysis was performed with highly polymorphic microsatellite markers, distributed over areas of the human genome harboring the most likely candidate genes. The most prevalent clinical manifestation in patients with Carney complex was spotty skin pigmentation, similar to that observed in Peutz-Jeghers and other lentiginosis syndromes. Skin and cardiac myxomas, Cushing syndrome, and acromegaly were present in 62, 30, 31 and 8 percent of the patients, respectively. Linkage was obtained for three markers on the short arm of chromosome 2 (2p16), with a maximum two-point lod score of 5.97 at theta = 0.03 for the marker CA-2 (odds in favor of linkage 10(6):1. The flanking markers CA7 and D2S378 defined a region of approximately 6.4 cM that is likely to contain the gene(s) associated with Carney complex. Candidate genes in the proximity, including the propiomelanocortin and the DNA-mismatch repair hMSH2 genes, were excluded. We conclude that the genetic defect(s) responsible for Carney complex map(s) to the short arm of chromosome 2 (2p16). This region has exhibited cytogenetic aberrations in atrial myxomas associated with the complex, and has been characterized by microsatellite instability in human neoplasias.

Acute glucocorticoid deficiency is associated with plasma elevations of interleukin-6: does the latter participate in the symptomatology of the steroid withdrawal syndrome and adrenal insufficiency?

The cytokines tumor necrosis factor-alpha (TNF alpha), interleukin-1 (IL-1), and IL-6 are secreted at inflammatory sites in tandem and play a crucial role in the inflammatory and wound-healing processes. All three cytokines are potent activators of the hypothalamic-pituitary-adrenal axis, through which they restrain inflammation, whereas IL-6 itself plays a role in the termination of inflammation as well. To test the hypothesis that endogenous glucocorticoids exert a negative tonic effect on the secretion of these cytokines, we studied 17 patients with Cushing's disease and 2 patients with primary adrenal Cushing's syndrome before and after surgery. Plasma TNF alpha, IL-1 beta and IL-6 were measured before surgery, while the patients were hypercortisolemic; on postoperative day 4 or 5, when they were hypocortisolemic; and on postoperative day 9 or 10, when they were receiving glucocorticoid replacement. During severe hypocortisolism, on postoperative day 4 or 5, plasma IL-6 levels rose significantly, compared to the preoperative values (P < 0.001). During the same interval, TNF alpha and IL-1 beta also rose, albeit to a lesser extent. Over the same interval, patients with severe hypocortisolism experienced temperature elevation, fatigue, somnolence, flu-like symptoms, and anorexia, symptoms that have been traditionally attributed to glucocorticoid deficiency; these were also experienced by subjects that received recombinant human IL-6. There was no postoperative increase in any of the cytokines studied in the patients who were not hypocortisolemic after surgery and who also lacked the corresponding symptomatology. Plasma IL-6 concentrations decreased significantly, albeit not to normal levels, in the hypocortisolemic group of patients on postoperative day 9 or 10, when they were receiving glucocorticoid replacement. We conclude that the peripheral levels of IL-6 and to a lesser extent, those of TNF alpha and IL-1 beta are tonically inhibited by basal levels of glucocorticoids. The increased IL-6 production that occurs when cortisol levels fall might explain the symptomatology of acute glucocorticoid deficiency.

Cushing's disease presenting with avascular necrosis of the hip: an orthopedic emergency.

Nontraumatic avascular necrosis (AVN) of the hip is commonly caused by exogenous glucocorticoid administration, whereas it has rarely been associated with endogenous hypercortisolism. We report a 30-yr-old woman with Cushing's disease whose presenting manifestation was early AVN of the hip. Although plain x-ray was negative, magnetic resonance imaging (MRI) of the hip showed stage 2 AVN. Her orthopedic disease was considered an emergency, and thus, it was treated with core decompression before the diagnosis of Cushing's syndrome (CS) was pursued further. The femur recovered fully, as demonstrated by her improved clinical picture and a subsequent MRI. AVN carries a poor prognosis, if not treated early. The diagnostic procedure of choice is MRI, because plain radiographs are falsely negative in early stages. This case illustrates that AVN can be the presenting manifestation of CS; to prevent irreversible effects on the femoral head, core decompression should not be delayed for the purpose of evaluation and treatment of CS.

Dose-dependent effects of recombinant human interleukin-6 on glucose regulation.

Inflammatory cytokines have metabolic actions that probably contribute to the general adaptation of the organism during infectious or inflammatory stress. To examine the effects of interleukin 6 (IL-6), the main circulating cytokine, on glucose metabolism in man, we performed dose-response studies of recombinant human IL-6 in normal volunteers. Increasing single doses of IL-6 (0.1, 0.3, 1.0, 3.0, and 10.0 mg/Kg BW) were injected sc in 15 healthy male volunteers (3 in each dose) after a 12-h fast. All IL-6 doses were tolerated well and produced no significant adverse effects. We measured the circulating levels of glucose, insulin, C-peptide, and glucagon at baseline and half-hourly over 4 h after the IL-6 injection. Mean peak plasma levels of IL-6 were achieved between 120 and 240 min and were 8, 22, 65, 290, and 4050 pg/mL, respectively, for the 5 doses. After administration of the 2 smaller IL-6 doses, we observed no significant changes in plasma glucose levels, which, because of continued fasting, decreased slightly over time. By 60 min after the 3 higher IL-6 doses, however, the decline in fasting blood glucose was arrested, and glucose levels increased in a dose-dependent fashion. The concurrent levels of plasma insulin and C-peptide were not affected by any IL-6 dose. In contrast, IL-6 caused significant increases in plasma glucagon levels, which peaked between 120 and 150 min after the IL-6 injection. In conclusion, sc IL-6 administration induced dose-dependent increases in fasting blood glucose, probably by stimulating glucagon release and other counteregulatory hormones and/or by inducing peripheral resistance to insulin action.

Elevation of plasma cytokines in disorders of excessive daytime sleepiness: role of sleep disturbance and obesity.

Excessive daytime sleepiness (EDS) and fatigue are frequent symptoms in the general population and the chief complaint of the majority of patients at Sleep Disorders Centers. There is evidence that the inflammatory cytokines tumor necrosis factor-alpha (TNF alpha), interleukin-1beta (IL-1beta), and IL-6 are involved in physiological sleep regulation and that their administration to humans is associated with sleepiness and fatigue. To explore whether plasma levels of TNF alpha, IL-1beta, and IL-6 are elevated in patients with EDS, we measured morning plasma levels of TNF alpha, IL-1beta, and IL-6 in 12 sleep apneics, 11 narcoleptics, 8 idiopathic hypersomniacs, and 10 normal controls. TNF alpha was significantly elevated in sleep apneics and narcoleptics compared to that in normal controls (P < 0.001 and P = 0.001, respectively). Plasma IL-1beta concentrations were not different between sleep disorder patients and controls, whereas IL-6 was markedly and significantly elevated in sleep apneics compared to that in normal controls (P = 0.028). The primary factor influencing TNF alpha values was the degree of nocturnal sleep disturbance, whereas the primary determinant for IL-6 levels was the body mass index. Our findings suggest that TNF alpha and IL-6 might play a significant role in mediating sleepiness and fatigue in disorders of EDS in humans.

A single midnight serum cortisol measurement distinguishes Cushing's syndrome from pseudo-Cushing states.

Cushing's syndrome (CS) may be difficult to distinguish from pseudo-Cushing states (PCS) based on physical findings or urinary glucocorticoid excretion. As the lack of diurnal variation in serum cortisol is characteristic of CS, we studied whether diurnal cortisol determinations could discriminate CS from PCS. Two hundred and sixty-three patients were evaluated: 240 had CS, and 23 had PCS. Urine was collected for 24 h for measurement of cortisol and 17-hydroxycorticosteroids (17OHCS). Blood was drawn at 2300, 2330, 0000, 0030, and 0100 h and at 0600, 0630, 0700, 0730, and 0800 h the next morning for serum cortisol determination. The main outcome measure was the sensitivity of these parameters for the diagnosis of CS at 100% specificity. A midnight cortisol value greater than 7.5 microg/dL correctly identified 225 of 234 patients with CS and all PCS patients. This sensitivity (96%) was superior to that obtained for any other measure, including urinary cortisol (45%), 17OHCS (22%), any other individual cortisol time point (10-92%), the morning (23%) or the evening (93%) cortisol mean, and the ratio (11%) of morning to evening values. We conclude that at 100% specificity, a single serum cortisol value above 7.5 microg/dL at midnight discriminates CS from PCS with higher sensitivity than 24-h urinary cortisol or 17OHCS, or other individual or combined measures of serum cortisol.

Rapid eye movement sleep correlates with the overall activities of the hypothalamic-pituitary-adrenal axis and sympathetic system in healthy humans.

To assess the association of the overall amount of rapid eye movement (REM) sleep and the activities of the hypothalamic-pituitary-adrenal axis and sympathetic system, we performed polysomnography and measured 24-h urinary free cortisol and catecholamine excretion in 21 healthy adults. After an adaptation night, each subject was recorded in the sleep laboratory for 3 consecutive nights while 24-h urine specimens were collected. Urinary free cortisol, epinephrine, dihydroxyphenylglycol, and dihydroxyphenylacetic acid levels were significantly and positively correlated with the average values of percent REM sleep (P < 0.05). There were no correlations between hormone values and REM latency, other variables of REM distribution, or REM density, an index of phasic activity during REM sleep. The positive correlations between stress system activity and REM sleep are consistent with hormonal and sleep alterations in melancholic depression, a state characterized by increased cortisol and catecholamine secretion.

Sleep apnea and daytime sleepiness and fatigue: relation to visceral obesity, insulin resistance, and hypercytokinemia.

Sleep apnea and associated daytime sleepiness and fatigue are common manifestations of mainly obese middle-aged men. The onset of sleep apnea peaks in middle age, and its morbid and mortal sequelae include complications from accidents and cardiovascular events. The pathophysiology of sleep apnea remains obscure. The purpose of this study was to test three separate, albeit closely related, hypotheses. 1) Does sleep apnea contribute to the previously reported changes of plasma cytokine (tumor necrosis factor-alpha and interleukin-6) and leptin levels independently of obesity? 2) Among obese patients, is it generalized or visceral obesity that predisposes to sleep apnea? 3) Is apnea a factor independent from obesity in the development of insulin resistance? Obese middle-aged men with sleep apnea were first compared with nonapneic age- and body mass index (BMI)-matched obese and age-matched lean men. All subjects were monitored in the sleep laboratory for 4 consecutive nights. We obtained simultaneous indexes of sleep, sleep stages, and sleep apnea, including apnea/hypopnea index and percent minimum oxygen saturation. The sleep apneic men had higher plasma concentrations of the adipose tissue-derived hormone, leptin, and of the inflammatory, fatigue-causing, and insulin resistance-producing cytokines tumor necrosis factor-alpha and interleukin-6 than nonapneic obese men, who had intermediate values, or lean men, who had the lowest values. Because these findings suggested that sleep apneics might have a higher degree of insulin resistance than the BMI-matched controls, we studied groups of sleep-apneic obese and age- and BMI-matched nonapneic controls in whom we obtained computed tomographic scan measures of total, sc, and visceral abdominal fat, and additional biochemical indexes of insulin resistance, including fasting plasma glucose and insulin. The sleep apnea patients had a significantly greater amount of visceral fat compared to obese controls (<0.05) and indexes of sleep disordered breathing were positively correlated with visceral fat, but not with BMI or total or sc fat. Furthermore, the biochemical data confirmed a higher degree of insulin resistance in the group of apneics than in BMI-matched nonapneic controls. We conclude that there is a strong independent association among sleep apnea, visceral obesity, insulin resistance and hypercytokinemia, which may contribute to the pathological manifestations and somatic sequelae of this condition.

Circadian interleukin-6 secretion and quantity and depth of sleep.

Patients with pathologically increased daytime sleepiness and fatigue have elevated levels of circulating interleukin-6 (IL-6). The latter is an inflammatory cytokine, which causes sickness manifestations, including somnolence and fatigue, and activation of the hypothalamic-pituitary-adrenal axis. In this study, we examined: 1) the relation between serial measurements of plasma IL-6 and quantity and depth of sleep, evaluated by polysomnography; and 2) the effects of sleep deprivation on the nyctohemeral pattern of IL-6 secretion. Eight healthy young male volunteers were sampled for 24 h twice, at the baseline state, after a normal night's sleep and after total overnight sleep deprivation. At the baseline state, IL-6 was secreted in a biphasic circadian pattern with two nadirs at 0800 and 2100 and two zeniths at 1900 and 0500 (P < 0.01). The baseline amount of sleep correlated negatively with the overall daytime secretion of the cytokine (P < 0.05). Also, depth of sleep at baseline correlated negatively with the postdeprivation increase of daytime secretion of IL-6 (P < 0.05). Sleep deprivation changed the temporal pattern of circadian IL-6 secretion but not the overall amount. Indeed, during the post-deprivation period, the mean daytime (0800-2200 h) levels of IL-6 were significantly higher (P < 0.05), whereas the nighttime (2200-0600 h) levels were lower than the predeprivation values. Thus, sleep-deprived subjects had daytime oversecretion and nighttime under-secretion of IL-6; the former might be responsible for their daylong somnolence and fatigue, the latter for the better quality (depth) of their sleep. These data suggest that a good night's sleep is associated with decreased daytime secretion of IL-6 and a good sense of well-being and that good sleep is associated with decreased exposure of tissues to the proinflammatory and potentially detrimental actions of IL-6. Sleep deprivation increases daytime IL-6 and causes somnolence and fatigue during the next day, whereas postdeprivation decreases nighttime IL-6 and is associated with deeper sleep.

Dose-dependent effects of recombinant human interleukin-6 on the pituitary-testicular axis.

Inflammatory cytokines are soluble mediators of immune function that also regulate intermediate metabolism and several endocrine axes. To examine the effects of interleukin-6 (IL-6), the main circulating cytokine, on the hypothalamic-pituitary-testicular axis in men, we performed dose-response studies of recombinant human IL-6 (rHuIL-6) in normal volunteers. Increasing single doses of IL-6 (0.1, 0.3, 1.0, 3.0, and 10.0 microg/kg body weight) were injected subcutaneously into 15 healthy male volunteers (3 at each dose) in the morning. We measured the circulating levels of testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and sex hormone binding globulin (SHBG) at baseline and then at 24 h, 48 h, and 7 days after the IL-6 injection. LH and FSH levels were also measured half-hourly for the first 4 h after the IL-6 injection. All IL-6 doses were tolerated well and produced no significant adverse effects. Mean peak plasma IL-6 levels achieved after IL-6 administration were 8 +/- 1, 22 +/- 5, 65 +/- 22, 290 +/- 38, and 4050 +/- 149 pg/ml, respectively for the five doses. We observed no significant changes in plasma testosterone levels after the two smaller IL-6 doses. The three higher IL-6 doses, however, caused significant decreases in testosterone levels by 24 h, which persisted at 48 h and returned to baseline by 7 days. The higher testosterone suppression was after the 3.0 microg/kg dose, making the dose-response curve bell-shaped. There also appeared to be small but not significant increases in LH levels after the three higher IL-6 doses, which were not acute and seemed to follow temporally the testosterone decreases. The concurrent plasma levels of FSH and SHBG were not appreciably affected by any IL-6 dose. In conclusion, subcutaneous IL-6 administration, which caused acute elevations in circulating IL-6 levels of a similar magnitude to those observed in severe inflammatory and noninflammatory stress, induced prolonged suppression in testosterone levels in healthy men without apparent changes in gonadotropin levels. This suggests that IL-6 might induce persistent testicular resistance to LH action or suppression of Leydig cell steroidogenesis or both, with potential adverse effects on male reproductive function.

Acute and delayed effects of a single-dose injection of interleukin-6 on thyroid function in healthy humans.

Interleukin-6 (IL-6) is produced in response to inflammatory and noninflammatory stress and acts as the principal regulator of the acute-phase protein response. IL-6 stimulates the hypothalamic-pituitary-adrenal axis and may be involved in the thyroid function abnormalities observed in nonthyroidal illness (NTI). This study examined the effects of single-dose IL-6 (3 microg/kg subcutaneously [s.c.]) in healthy human subjects: 19 received IL-6 and 13 received control saline injection. The dose of IL-6 was chosen on the basis of previous studies indicating that the peak IL-6 level after injection reaches concentrations observed with major stress such as abdominal surgery. Plasma levels of thyrotropin (TSH), free thyroxine (FT4), total T4, 3,5-3'-L-triiodothyronine (T3), 3,3'-5'-L-triiodothyronine or reverse T3 (rT3), and thyroxine-binding globulin (TBG) were measured over a 4-hour period and 24 hours after IL-6 injection. Plasma TSH levels were 27% lower 240 minutes after IL-6 relative to control levels (0.93 +/- 0.10 v 1.28 +/- 0.18 mIU/mL, P = .001), but recovered by 24 hours. Plasma FT4 was elevated at 240 minutes compared with the controls (1.16 +/- 0.04 v 1.03 +/- 0.03 ng/dL, P = .0002). T4 levels were also elevated at 240 minutes (7.8 +/- 0.36 v 7.05 +/- 0.37 microg/dL, P = .0003). TBG levels were not significantly changed at this time point. At 24 hours, T3 levels were 19% lower than the control values (87.6 +/- 5.1 v 108.5 +/- 5.4 ng/dL, P = .0002); plasma rT3 levels were elevated by 21% compared with control levels (30.6 +/- 1.7 v 24.3 +/- 1.3 ng/dL, P = .002), while FT4 levels returned to normal. The changes in T3/rT3 levels were reminiscent of the pattern observed in NTI that may be due to inhibition of type-1 5'-deiodinase. Cortisol levels were greatly elevated after IL-6 compared with control values; peak levels were observed 120 minutes after IL-6 injection (28.7 +/- 1.6 v 9.5 +/- 1.0 ng/dL, P < .0001). This elevation in cortisol may have contributed to the suppression of TSH levels and inhibition of type-1 5'-deiodinase activity. Alternatively, IL-6 may have suppressed TSH secretion via a direct suprapituitary action. The elevation of T4 and FT4 levels may have been due to inhibition of T4 degradation at the liver and/or by direct action of IL-6 on the thyroid gland. These findings demonstrate the potent effects of IL-6 on thyroid hormone metabolism in healthy individuals, and suggest that IL-6 may act directly or indirectly at two or more sites on thyroid hormone secretion and metabolism.

Chronic insomnia is associated with a shift of interleukin-6 and tumor necrosis factor secretion from nighttime to daytime.

Chronic insomnia, by far the most commonly encountered sleep disorder in medical practice, is characterized by difficulty falling or staying asleep at night and increased fatigue during the day. Interleukin-6 (IL-6) and tumor necrosis factor (TNF) are fatigue-inducing cytokines, and the daytime secretion of IL-6 is negatively influenced by the quantity and quality of the previous night's sleep. We hypothesize that the poor quality of insomniacs' sleep is associated with a hypersecretion of these 2 cytokines during the daytime, which, in turn, correlates with the fatigue experienced by these patients. Eleven young insomniacs (6 men and 5 women) and 11 (8 men and 3 women) age- and body mass index (BMI)-matched healthy controls participated in the study. Subjects were recorded in the sleep laboratory for 4 consecutive nights and serial 24-hour plasma measures of IL-6 and TNF were obtained during the 4th day. Insomniacs compared to controls slept poorly (sleep latency and wake were increased, whereas percentage sleep time was decreased during baseline nights, all P <.05). The mean 24-hour IL-6 and TNF secretions were not different between insomniacs and controls. However, the difference in the change (increase) of IL-6 plasma levels from midafternoon (2 PM) to evening (9 PM) between insomniacs and controls was significant (P <.01). Furthermore, cosinor analysis showed a significant shift of the major peak of IL-6 secretion from nighttime (4 AM) to evening (7 PM) in insomniacs compared to controls (P <.05). Also, while TNF secretion in controls showed a distinct circadian rhythm with a peak close and prior to the offset of sleep (P <.05), such a rhythm was not present in insomniacs. Finally, daytime secretion of TNF in insomniacs was characterized by a regular rhythm of 4 hours (P <.05); such a distinct periodicity was not present in controls. We conclude that chronic insomnia is associated with a shift of IL-6 and TNF secretion from nighttime to daytime, which may explain the daytime fatigue and performance decrements associated with this disorder. The daytime shift of IL-6 and TNF secretion, combined with a 24-hour hypersecretion of cortisol, an arousal hormone, may explain the insomniacs' daytime fatigue and difficulty falling asleep.

Neuroendocrine responses to running in women after zinc and vitamin E supplementation.

PURPOSE: The study was undertaken to determine whether acute supplementation with zinc or vitamin E would modify neuroendocrine responses to physiologic stress. METHODS: Specifically, the effects of exhaustive running on blood glucose, lactate, ACTH, cortisol, growth hormone, prolactin, catecholamine, and interleukin 6 (IL-6) concentrations were determined in 10 eumenorrheic runners after supplementation with zinc (25 mg), vitamin E (400 IU), or placebo. Subjects ran at 65-70% of their VO2max, to exhaustion, on a treadmill during the follicular phase of their menstrual cycles over three cycles. RESULTS: There were no significant differences associated with supplementation for any of the hormonal and metabolic measures. Exercise, however, significantly (P<0.05) increased plasma lactate, ACTH, prolactin, and catecholamine concentrations, all of which peaked immediately after exercise (POST). Plasma cortisol concentrations were significantly (P<0.05) elevated at POST, and a further increase was noted 1 h after exercise. IL-6 concentrations rose linearly throughout exercise and reached peak values at POST. Exercise-induced changes were transient in that all measures returned to baseline within 24 h. CONCLUSIONS: Acute supplementation with zinc or vitamin E did not influence the effects of exhaustive running on metabolic and endocrine responses in women. The effects of chronic supplementation on neuroendocrine responses to exercise remain to be determined.

A phase IIA randomized, placebo-controlled clinical trial to study the efficacy and safety of the selective androgen receptor modulator (SARM), MK-0773 in female participants with sarcopenia.

BACKGROUND: Sarcopenia, the age-related loss of muscle mass [defined as appendicular LBM/Height2 (aLBM/ht2) below peak value by>1SD], strength and function, is a major contributing factor to frailty in the elderly. MK-0773 is a selective androgen receptor modulator designed to improve muscle function while minimizing effects on other tissues. OBJECTIVES: The primary objective of this study was to demonstrate an improvement in muscle strength and lean body mass (LBM) in sarcopenic frail elderly women treated with MK-0773 relative to placebo. DESIGN: This was a randomized, double-blind, parallel-arm, placebo-controlled, multicenter, 6-month study. Participants were randomized in a 1:1 ratio to receive either MK-0773 50mg b.i.d. or placebo; all participants received Vitamin D and protein supplementation. SETTING: General community. PARTICIPANTS: 170 Women aged ≥65 with sarcopenia and moderate physical dysfunction. MEASUREMENTS: Dual energy X-ray absorptiometry, muscle strength and power, physical performance measures. RESULTS: Participants receiving MK-0773 showed a statistically significant increase in LBM from baseline at Month 6 vs. placebo (p<0.001). Participants receiving both MK-0773 and placebo showed a statistically significant increase in strength from baseline to Month 6, but the mean difference between the two groups was not significant (p=0.269). Both groups showed significant improvement from baseline at Month 6 in physical performance measures, but there were no statistically significant differences between participants receiving MK-0773 and placebo. A greater number of participants experienced elevated transaminases in the MK-0773 group vs. placebo, which resolved after discontinuation of study therapy. MK-0773 was generally well-tolerated with no evidence of androgenization. CONCLUSIONS: The MK-0773-induced increase in LBM did not translate to improvement in strength or function vs. placebo. The improvement of strength and physical function in the placebo group could be at least partly attributed to protein and vitamin D supplementation.

Interactions of the endocrine and immune systems in children and young adults.

In the recent past, we have seen novel information on the bidirectional interactions between the endocrine and immune systems. Thus, the central nervous system, through the hypothalamic-pituitary-adrenal axis and the peripheral autonomic and sensory systems, influences the quantity and the quality of the immune and inflammatory reactions. The latter, on the other hand, regulates the activity of the endocrine system by influencing its central and peripheral components. The reciprocal effects of the two systems on each other are adaptive and help survival of the self and species. Dysregulation or chronic alterations of the endocrine system can, however, increase the susceptibility of individuals to various diseases or lead to frank pathologic states.

Nighttime salivary cortisol measurement as a simple, noninvasive, outpatient screening test for Cushing's syndrome in children and adolescents.

OBJECTIVE: There is currently no optimal test to screen for endogenous Cushing's syndrome (CS) in children. Traditional 24-hour urine or midnight serum cortisol values may be difficult to obtain or elevated by venipuncture stress. We hypothesized that salivary cortisol measurement is a reliable way to screen for CS in children. STUDY DESIGN: Sixty-seven children (5-17 years) were studied: 24 obese volunteers, 29 non-obese volunteers, and 14 children with CS. Saliva was obtained at 7:30 AM, bedtime, and midnight for measurement of free cortisol by radioimmunoassay. RESULTS: Salivary cortisol was detectable in all morning and evening samples from patients with CS but was frequently undetectable in healthy children at bedtime (66%) and at midnight (90%). With cut points that excluded healthy children, a midnight salivary cortisol value of 7.5 nmol/L (0.27 microg/dL) identified 13 of 14 patients with CS, whereas a bedtime value >27.6 nmol/L (1 microg/dL) detected CS in 5 of 6 patients. The diagnostic accuracies of midnight salivary cortisol and urinary free cortisol per square meter were the same (93%). CONCLUSION: Salivary cortisol measurement at bedtime or midnight rules out CS in nearly all cases. Nighttime salivary cortisol sampling is thus a simple, accurate way to screen for hypercortisolism in children.