Metyrapone Challenge Research Articles

The roles of comorbidity and trauma exposure and its timing in shaping HPA axis patterns in depression

BackgroundMuch work has documented hypothalamic pituitary adrenal (HPA) axis abnormalities in major depressive disorder (MDD), but inconsistencies leave this system’s role in the illness unclear. Comparisons across studies are complicated by variation in co-morbidity (Posttraumatic Stress Disorder-PTSD, anxiety disorders), exposure to trauma, and timing of trauma (child vs. adult). Here, we examined the impact of these factors on HPA axis profiles in depression. MethodsWe recruited 5 groups of participants: MDD (n = 14), comorbid MDD + PTSD following adulthood trauma (MDD + PTSD-Adult; n = 12), comorbid MDD + PTSD following childhood trauma (MDD + PTSD-Child; n = 18), comorbid MDD + social anxiety disorder (MDD + SAD; n = 12), and non-depressed control participants who were sex and age matched to patients (combined total n = 36). HPA axis function was assessed using three challenges: stress reactivity via the Trier Social Stress Test (TSST), feedback sensitivity via a dexamethasone suppression test (DST), and central drive via a metyrapone challenge (MET). We compared hormonal responses between patient groups and their respective non-depressed controls. ResultsMDD + PTSD-Child showed low cortisol levels at baseline, and reduced adrenocorticotropic hormone (ACTH) levels at baseline and throughout the TSST. MDD-only, MDD + PTSD-Adult, and MDD + SAD did not differ from non-depressed controls in HPA axis responses to the TSST. Controlling for childhood trauma severity, the reduced baseline levels in MDD + PTSD-Child were no longer significant and significantly reduced baseline cortisol levels emerged for MDD + PTSD-Adult. No diagnostic group effects were detected with DST and MET. Childhood maltreatment subtypes were associated with unique HPA axis responses to TSST and MET. ConclusionComorbidity and trauma exposure, as well as their timing and type, contribute to inconsistencies in the depression literature and must be included in efforts to clarify the role of the HPA axis in MDD.

Sleep and hypothalamic pituitary adrenal axis responses to metyrapone in posttraumatic stress disorder

Disturbed sleep is a core feature of posttraumatic stress disorder (PTSD), characterized in part by decreased delta power sleep that may result from stress-related alterations in corticotropin releasing factor (CRF), hypothalamic pituitary adrenal axis (HPA) regulation and glucocorticoid signaling. Overnight HPA axis response mediating sleep disturbances in men and women with PTSD was examined using a metyrapone challenge. Metyrapone blocks cortisol synthesis, removing negative feedback, and increases the release of hypothalamic CRF and pituitary adrenocorticotropic hormone (ACTH). Laboratory-based polysomnography was used to monitor the sleep of 66 medically healthy, medication-free men and pre-menopausal follicular phase women including 33 with chronic PTSD (16 women and 17 men) and 33 age- and sex-matched controls (14 women and 19 men) over 3 consecutive nights. Participants completed an overnight metyrapone challenge after an adaptation and baseline night of sleep and ACTH was obtained by repeated blood sampling. Metyrapone resulted in a greater increase in ACTH and greater decreases in cortisol and delta spectral power sleep in PTSD subjects compared to controls, and a greater increase in ACTH in women compared to men. There was no sex difference in metyrapone effects on delta power sleep, and no significant metyrapone by PTSD by sex interactions with either ACTH or delta power sleep. Regression analyses indicated that a greater increase in ACTH response was associated with a greater decrease in delta power sleep response in PTSD subjects, but no such relationship was found in controls. The PTSD group difference was similar in men and women. These results suggest that stress-related alterations of the HPA axis in PTSD may contribute to sleep difficulties. Therapeutics that target the HPA axis may offer promise as a potential future treatment for PTSD and related sleep difficulties.

Cross-reactivity of steroid hormone immunoassays: clinical significance and two-dimensional molecular similarity prediction.

BackgroundImmunoassays are widely used in clinical laboratories for measurement of plasma/serum concentrations of steroid hormones such as cortisol and testosterone. Immunoassays can be performed on a variety of standard clinical chemistry analyzers, thus allowing even small clinical laboratories to do analysis on-site. One limitation of steroid hormone immunoassays is interference caused by compounds with structural similarity to the target steroid of the assay. Interfering molecules include structurally related endogenous compounds and their metabolites as well as drugs such as anabolic steroids and synthetic glucocorticoids.MethodsCross-reactivity of a structurally diverse set of compounds were determined for the Roche Diagnostics Elecsys assays for cortisol, dehydroepiandrosterone (DHEA) sulfate, estradiol, progesterone, and testosterone. These data were compared and contrasted to package insert data and published cross-reactivity studies for other marketed steroid hormone immunoassays. Cross-reactivity was computationally predicted using the technique of two-dimensional molecular similarity.ResultsThe Roche Elecsys Cortisol and Testosterone II assays showed a wider range of cross-reactivity than the DHEA sulfate, Estradiol II, and Progesterone II assays. 6-Methylprednisolone and prednisolone showed high cross-reactivity for the cortisol assay, with high likelihood of clinically significant effect for patients administered these drugs. In addition, 21-deoxycortisol likely produces clinically relevant cross-reactivity for cortisol in patients with 21-hydroxylase deficiency, while 11-deoxycortisol may produce clinically relevant cross-reactivity in 11β-hydroxylase deficiency or following metyrapone challenge. Several anabolic steroids may produce clinically significant false positives on the testosterone assay, although interpretation is limited by sparse pharmacokinetic data for some of these drugs. Norethindrone therapy may impact immunoassay measurement of testosterone in women. Using two-dimensional similarity calculations, all compounds with high cross-reactivity also showed a high degree of similarity to the target molecule of the immunoassay.ConclusionsCompounds producing cross-reactivity in steroid hormone immunoassays generally have a high degree of structural similarity to the target hormone. Clinically significant interactions can occur with structurally similar drugs (e.g., prednisolone and cortisol immunoassays; methyltestosterone and testosterone immunoassays) or with endogenous compounds such as 21-deoxycortisol that can accumulate to very high concentrations in certain disease conditions. Simple similarity calculations can help triage compounds for future testing of assay cross-reactivity.

Sex differences in neurosteroid and hormonal responses to metyrapone in posttraumatic stress disorder.

Mechanisms contributing to sex differences in the regulation of acute stress responsivity and their effect on the increased incidence of posttraumatic stress disorder (PTSD) in women are poorly understood. The reproductive hormone, progesterone, through conversion to allopregnanolone (ALLO), suppresses the hypothalamic pituitary adrenal (HPA) axis and has potent anxiolytic effects. The potential that progesterone and allopregnanolone reactivity modulate HPA axis responses and account for sex differences in PTSD has not been previously examined. The present study examined the effects of sex and PTSD on adrenocorticotropic hormone (ACTH), progesterone, and allopregnanolone responses to metyrapone and whether progesterone and allopregnanolone reactivity could affect the ACTH response in PTSD. Healthy medication-free male and premenopausal follicular phase female participants with chronic PTSD (n = 43; 49 % female) and controls (n = 42; 50 % female) completed an overnight metyrapone challenge and ACTH, progesterone, and allopregnanolone were obtained by repeated blood sampling. The increase in ACTH response to metyrapone was higher in PTSD subjects compared to controls and in women compared to men. Contrary to our initial prediction of an inverse relationship, progesterone and allopregnanolone were positively associated with ACTH. Progesterone and allopregnanolone partially mediated the relationship between PTSD and ACTH. Our findings of increased ACTH to metyrapone in PTSD and in women may reflect heightened hypothalamic CRF hypersecretion. Progesterone and allopregnanolone partially mediated the ACTH response in PTSD. Further characterizing sex differences in these processes will advance our understanding of the pathophysiology of PTSD, and may ultimately lead to better-targeted, more effective treatment.

Mood and Neuroendocrine Response to a Chemical Stressor, Metyrapone, in Buprenorphine-Maintained Heroin Dependence

Heroin dependence is associated with a hyperactive hypothalamic-pituitary-adrenal (HPA) axis, proposed as a biological correlate of craving. Maintenance treatment with methadone normalizes HPA axis activity. Here, we examined HPA axis activity under maintenance treatment with the increasingly utilized partial opiate agonist buprenorphine. Responses to a metyrapone challenge were compared in 20 buprenorphine-maintained heroin addicts and 20 healthy volunteers (10 received a single 50 mg naltrexone dose [NTX+] and 10 received no naltrexone [NTX-]). Patients were 16 male subjects and 4 female subjects, aged 30 to 38 years, heroin-dependent and relapse-free under buprenorphine maintenance (BUP) for a minimum of 6 months. Healthy volunteers were 9 male subjects and 11 female subjects, aged 36 to 49 years, with no history of dependence. Serial measures were obtained of plasma adrenocorticotropic hormone (ACTH) and cortisol and Profile of Mood States (POMS) ratings over time. Subjects were genotyped for the OPRM1 118A/G polymorphism. Buprenorphine maintenance showed a dampened HPA axis response to metyrapone, with OPRM1 118G carriers showing a significantly attenuated response compared with 118A carriers. The response of the NTX+ group was markedly increased. In contrast, negative affect was elevated in the BUP group but did not differ between NTX- and NTX+. Buprenorphine maintenance and NTX- groups did not differ in positive affect, whereas the NTX+ group was lower. In contrast to exaggerated HPA axis responsiveness reported in untreated heroin dependence, response to metyrapone was subnormal in heroin addicts maintained on buprenorphine. Despite this, increased measures of negative affect were seen in this group. This implies a dissociation of HPA axis responsiveness and affect in heroin dependence.

Neuroendocrine Regulation of Sleep Disturbances in PTSD

Studies that have conducted quantitative analysis of the sleep electroencephalogram (EEG) have demonstrated decreased delta sleep in PTSD. Elevations in both hypothalamic (neurohormonal) and extrahypothalamic (neurotransmitter) corticotropin releasing factor (CRF) release is associated with decreased delta sleep activity. We present data from several studies examining the effect of metyrapone administration on the sleep EEG in PTSD and control subjects. Plasma ACTH, cortisol, and 11-deoxycorticol were obtained the morning following polysomnographic sleep recordings before and after metyrapone administration. Delta sleep was measured by period amplitude analysis. The results demonstrate: a) decreased delta sleep in male subjects with PTSD; b) metyrapone administration resulted in an activation of the sleep EEG and a robust decrease in quantitative delta sleep; c) the sleep and endocrine (increase in ACTH) responses to metyrapone were significantly decreased in PTSD in two different study samples; and d) the metyrapone-related disruption to sleep in both samples was predicted by the increase in ACTH measured the following morning. These findings strongly suggest that the delta sleep response to metyrapone is a measure of the brain response to a hypothalamic CRF challenge. The attenuated delta sleep and endocrine response to metyrapone challenge in PTSD is consistent with a model of enhanced negative feedback regulation or downregulation of CRF receptors in an environment of chronically increased CRF activity.

Periconceptional undernutrition in sheep accelerates maturation of the fetal hypothalamic-pituitary-adrenal axis in late gestation.

We investigated the effects of moderate maternal periconceptional undernutrition from 60 d before to 30 d after mating on fetal hypothalamic-pituitary-adrenal axis function in late gestation. Ewes were sampled regularly during the period of undernutrition for circulating hormone levels. Vascular catheters were inserted into ewes and their singleton fetuses at 112 d gestation (term, 145 d), and fetal ACTH(1-24) and metyrapone challenge tests were performed at 127 and 128 d. Postmortems were performed at 132 d. Fetuses of undernourished ewes (UN, n = 12) had elevated baseline cortisol concentrations (P < 0.05), compared with fetuses of ad libitum-fed ewes (n = 10). There were no differences between groups in fetal responses to ACTH challenge, but only UN fetuses demonstrated ACTH and 11-deoxycortisol responses to metyrapone (P < 0.05). UN fetuses had increased mRNA levels for proopiomelanocortin and prohormone convertase-1, but not -2, in the pars intermedia of the pituitary gland (P < 0.05). Glucocorticoid receptor mRNA levels were not different between groups in pituitary or hypothalamus. Maternal cortisol and ACTH levels during undernutrition were profoundly suppressed (P < 0.001), rather than elevated, in UN ewes. Furthermore, the normal pregnancy rise in maternal serum progesterone concentrations was delayed in undernourished mothers. These data demonstrate that events around the time of conception have profound effects on fetal hypothalamic-pituitary-adrenal development in late gestation and that factors other than fetal exposure to excess glucocorticoids may be important.

HPA axis activation in major depression and response to fluoxetine: a pilot study

Hypothalamic-pituitary–adrenal (HPA) axis activation is a frequently observed phenomenon in major depression. However, whether this activation has any implications for treatment is unknown. To address this question, we examined baseline response to metyrapone and 6-week response to fluoxetine. Premenopausal women ( n=20) who met criteria for major depression with no other confounding Axis I disorders, medications, or medical illnesses and were not taking hormonal contraceptives were evaluated with an evening metyrapone challenge before the onset of treatment. Twenty-one normal women were also studied with the evening metyrapone challenge. The depressed patients then entered an open label treatment with fluoxetine for 6 weeks. Subjects were classified as responders if they demonstrated a 50% or greater decrease in Hamilton Depression Rating Scale rating. As a group, the depressed women demonstrated significantly increased ACTH secretion compared to control women before the onset of treatment, during the metyrapone challenge. Before treatment, women who were non-responders to fluoxetine showed increased HPA axis activation compared to controls, while the fluoxetine responders did not differ significantly from normal subjects in their ACTH levels during metyrapone challenge. These results suggest that overactivity of the HPA axis may be one factor associated with slower response to fluoxetine. This may reflect the greater severity of subjects with HPA axis dysregulation or the need to normalize the HPA axis with medications for optimal response.

Effect of Endogenous Cortisol Levels on Natural Killer Cell Activity in Healthy Humans

The aim of this study was to examine the effects of increasing and decreasing endogenous cortisol levels on natural killer (NK) cell activityin vivo.Normal healthy volunteers participated in the following studies: baseline (n= 27), metyrapone challenge test (n= 10), dexamethasone suppression test (n= 10), and adrenocorticotropic hormone (ACTH) stimulation test (n= 8). Each subject served as his own control for each study. Each subject was tested for NK activity and plasma cortisol levels at 9a.m., just before the challenge drug administration, and at 10a.m., except for the dexamethasone study, in which only the 9a.m.blood was drawn, 10 h after the dexamethasone administration. On the baseline study day, a significant decrease in plasma cortisol levels was found from 9 to 10a.m.(p< .02) along with a significant increase in NK activity (p< .001). On the metyrapone test day, plasma cortisol levels at 10a.m.were significantly reduced (p< .005) as expected, while NK activity at the same time point was not affected and was increased to an extent equivalent to the baseline study day. On the dexamethasone test day, plasma cortisol concentrations were significantly decreased (p< .0001) as compared to the same time point on the baseline day, without any significant change in the NK activity. On the ACTH test day, plasma cortisol rose significantly at 10a.m.(p< .02), with no change in NK activity. We conclude that plasma cortisol alone has no significant effect on NK activityin vivo.

The role of the low dose (1 microgram) adrenocorticotropin test in the evaluation of patients with pituitary diseases.

The role of the low dose (1 microgram) ACTH stimulation test in the evaluation of patients with pituitary diseases was systematically assessed by relating its results to those obtained on gold standard tests of hypothalamo-pituitary-adrenal (HPA) reserve, such as insulin-induced hypoglycemia or a metyrapone challenge. Ten patients with pituitary diseases (8 men and 2 women) and proven impairment of HPA function and 9 patients (5 men and 4 women) with similar pituitary pathologies but preserved HPA function were studied (pituitary controls). A group of 7 normal volunteers (3 men and 4 women) served as normal controls. None of the subjects was taking glucocorticoids on a chronic basis or had been taking any recently. All subjects underwent ACTH tests at 0800 h with 3 different levels of stimulation (1, 5, and 250 micrograms), and serum cortisol was assayed 0, 30, and 60 min after injection. A pass result was defined as a peak cortisol value of 497 nmol/L or more. Basal cortisol values were indistinguishable among the groups. Pituitary controls did not differ from normal controls for any of the challenges. In healthy controls, peak cortisol levels attained with the low dose stimulation were clearly lower than with the standard dose (670 +/- 39 vs. 919 +/- 50 nmol/L; P = 0.002). However, every normal control passed the low dose stimulation, whereas none of the patients with impaired HPA function did (P = 0.00005). Although the cortisol values achieved on the standard (250 micrograms) dose by the subjects with impaired HPA function were significantly lower than those in normal controls (P < 0.005), they were generally normal in absolute terms. Indeed, using the peak value criterion, 7 of these 10 patients would have qualified as pass on the 5-micrograms challenge, and 9 of 10 would have passed the 250-micrograms test. Thus, the low dose ACTH test appears to perform better than the standard pharmacological test. As we have shown that this test correlates well with reference tests of HPA function, it is suggested that it should replace the standard ACTH test in the diagnosis of secondary adrenal insufficiency.

Adrenal Function During Chronic Danazol Administration

Ten healthy female volunteers received Danazol, 400 mg twice daily for 90 days. Adrenal function testing then showed a normal capacity of the gland to respond to stimulation with synthetic adrenocorticotrophic hormone, and a lack of suppression of central areas controlling adrenal function by a normal response to the metyrapone challenge.