Single-dose Metyrapone Research Articles

Acute stress response of the HPA-axis in children with Prader-Willi syndrome: new insights and consequences for clinical practice.

Prader-Willi syndrome (PWS) is associated with hypothalamic dysfunction. It has been reported that the HPA axis might show a delayed response during acute stress, and it is unknown whether the response of the HPA-axis during acute stress changes with age in children with PWS. To investigate the HPA-axis response during an overnight single-dose metyrapone (MTP) test in children with PWS and to assess if the response changes with age, whether it is delayed and if it changes with repeated testing over time. In addition, we evaluated different cut-off points of ACTH and 11-DOC levels to assess stress-related central adrenal insufficiency (CAI). An overnight single-dose MTP test was performed in 93 children with PWS. Over time, 30 children had a second test and 11 children a third one. Children were divided into age groups (0-2 years, 2-4 years, 4-8 years and > 8 years). Most children did not have their lowest cortisol level at 7.30h, but at 04.00h. Their ACTH and 11-DOC peaks appeared several hours later, suggesting a delayed response. When evaluated according to a subnormal ACTH peak (13-33 pmol/L) more children had an subnormal response compared to evaluation based on a subnormal 11-doc peak (< 200 nmol/L). The percentage of children with a subnormal ACTH response ranged from 22.2 to 70.0% between the age groups, while the percentage of a subnormal 11-DOC response ranged from 7.7 to 20.6%. When using the ACTH peak for diagnosing acute-stress-related CAI, differences between age groups and with repeated testing over time were found, whereas there was no age difference when using the 11-DOC peak. Early morning ACTH or 11-DOC levels are not appropriate to determine acute stress-related CAI in children with PWS, thus multiple measurements throughout the night are needed for an accurate interpretation. Our data suggest a delayed response of the HPA-axis during acute stress. Using the 11-DOC peak for the test interpretation is less age-dependent than the ACTH peak. Repeated testing of the HPA-axis over time is not required, unless clinically indicated.

Ghrelin stimulation by hypothalamic-pituitary-adrenal axis activation depends on increasing cortisol levels.

Ghrelin plasma concentration increases in parallel to cortisol after a standardized psychological stress in humans, but the physiological basis of this interaction is unknown. We aimed to elucidate this question by studying the ghrelin response to pharmacological manipulation of the hypothalamic–pituitary–adrenal (HPA) axis. Six lean, healthy male volunteers were examined under four experimental conditions. Blood samples were collected every 30 min for two sequential periods of two hours. Initially, a baseline period was followed by intravenous injection of a synthetic analog of ACTH (250 μg). Subsequently, a single dose of metyrapone was administered at midnight and in the following morning, blood samples were collected for 2 h, followed by an intravenous injection of hydrocortisone (100 mg) with continued sampling. We show that increased cortisol serum levels secondary to ACTH stimulation or hydrocortisone administration are positively associated with plasma ghrelin levels, whereas central stimulation of the HPA axis by blocking cortisol synthesis with metyrapone is associated with decreased plasma ghrelin levels. Collectively, this suggests that HPA-axis-mediated elevations in ghrelin plasma concentration require increased peripheral cortisol levels, independent of central elevation of ACTH and possibly CRH levels.

High Prevalence of Central Adrenal Insufficiency in Patients with Prader-Willi Syndrome

The annual death rate of Prader-Willi syndrome (PWS) patients is very high (3%). Many of these deaths are sudden and unexplained. Because most deaths occur during moderate infections and PWS patients suffer from various hypothalamic insufficiencies, we investigated whether PWS patients suffer from central adrenal insufficiency (CAI) during stressful conditions. Overnight single-dose metyrapone tests were performed. Metyrapone (30 mg/kg) was administered at 2330 h. At 0400, 0600, and 0730 h, ACTH, 11-deoxycortisol, cortisol, and glucose levels were measured. Diurnal salivary cortisol profiles were assessed on a different day at wake-up, 30 min after wake-up, at 1400 h, and at 2000 h. The study was conducted in a pediatric intensive care unit. Patients included 25 randomly selected PWS patients. Patients were considered as having CAI when ACTH levels remained below 33 pmol/liter at 0730 h. Median (interquartile range) age was 9.7 (6.8-13.6) yr. Fifteen patients (60%) had an insufficient ACTH response (CAI, P < 0.001). There was no significant difference in age, gender, genotype, and body mass index SD score between patients with CAI and those without. Morning salivary cortisol levels and diurnal profiles were normal in all children, suggesting that CAI becomes apparent only during stressful conditions. Strikingly, 60% of our PWS patients had CAI. The high percentage of CAI in PWS patients might explain the high rate of sudden death in these patients, particularly during infection-related stress. Based on our data, one should consider treatment with hydrocortisone during acute illness in PWS patients unless CAI has recently been ruled out with a metyrapone test.

A single dose of metyrapone caused long-term dysregulation of the hypothalamic–pituitary–adrenal axis in the rat

There is evidence that metyrapone (MET), apart from its inhibition of 11-β steroid hydroxylation, may exert some stress-like effects in the brain, including the activation of the hypothalamic–pituitary–adrenal (HPA) axis and the induction of c-fos. Since a single exposure to some stressors has been found to exert long-term effects on the HPA axis, we hypothesized that a single dose of MET (200 mg/kg, s.c.) could exert even stronger effects, due to the combination of its stressful properties with the lack of constrain of the HPA axis by glucocorticoids. Whereas the inhibitory effect of the drug on corticosterone secretion lasted less than 24 h, its stimulatory effect on the HPA axis could be seen for at least 2 days after the injection. Surprisingly, on day 8, an exacerbated HPA response to immobilization stress was observed in MET rats, despite complete normalization of resting levels of HPA hormones. At this time it was also observed, under basal conditions, increased levels of mRNA for CRH and arginin–vasopressin in the parvocellular region of the paraventricular nucleus of the hypothalamus (pPVN), along with reduced mRNA for glucocorticoid receptors in dentate gyrus and hippocampus CA1, but not in pPVN or medial prefrontal cortex. These data suggest that a single MET administration can exert a marked and long-lasting dysregulation of both resting and stress-induced activity of the HPA axis. Thus, attention should be paid to these properties when using the drug to study the functional role of glucocorticoids.

Effect of single doses of dexamethasone and adrenocorticotrop hormone on serum bone markers in healthy subjects and in patients with adrenal incidentalomas and Cushing’s syndrome

The aim of the present study was to explore whether short-term changes in glucocorticoid activity which occur during dynamic testing of the pituitary adrenal axis with dexamethasone, ACTH, or metyrapone could have an effect on serum osteocalcin (OC) and beta-crosslaps (beta-CTx) concentrations in healthy subjects, in patients with adrenal incidentalomas and in those with Cushing's syndrome. The study included 40 healthy subjects (35 women and 5 men, age range 18-69 yr), 49 patients with adrenal incidentalomas (34 women and 15 men, age range 19-77 yr) and 8 patients with Cushing's syndrome (5 cortisol-producing adenomas and 3 pituitary-dependent Cushing's syndrome, 3 women and 5 men, age range 19-70 yr). Serum OC and beta-CTx concentrations were determined with electrochemoluminescent immunoassays at midnight, after an overnight fast between 08:00 and 09:00 h, after an overnight dexamethasone test (1 mg, orally) and after a single dose of metyrapone (30 mg/kg, orally). In healthy subjects and in patients with adrenal incidentalomas, serum bone marker concentrations were also measured after a single dose of ACTH injection (Cortrosyn depot, 1 mg im). Patients with Cushing's syndrome, but not those with adrenal incidentalomas, showed significantly lower serum OC at midnight (18.5+/-12 ng/ml, mean+/-SD) and between 08:00 and 09:00 h (17.7+/-9.6 ng/ml) compared to corresponding values obtained in healthy subjects (24.5+/-7.0 and 28.3+/-12.2 ng/ml, respectively). Serum OC concentrations were significantly decreased after a single dose of 1-mg dexamethasone in healthy subjects (from 28.3+/-12.2 to 21.8+/-9.5 ng/ml) and in patients with adrenal incidentalomas (from 29.8+/-15.9 to 24.1+/-14.1 ng/ml), whereas serum OC concentrations remained unchanged in patients with Cushing's syndrome. In addition, serum OC concentrations were even more markedly decreased after a single dose of ACTH injection in both healthy subjects (12.5+/-4.6 ng/ml) and in patients with adrenal incidentalomas (12.2+/-6.5 ng/ml). By contrast, metyrapone administration failed to induce significant changes in OC levels. There were no significant differences in beta-CTx concentrations between the three groups or after drug treatments. Thus, serum OC levels should be interpreted with caution when obtained during testing of the pituitary-adrenal axis with dexamethasone or ACTH.

Testing the hypothalamic-pituitary-adrenal axis in survivors of childhood brain and skull-based tumors.

The objective of this study was to determine whether a low dose of ACTH (0.2 microg/kg) improves the sensitivity of ACTH testing in detecting hypothalamic-pituitary-adrenal (HPA) axis abnormalities in survivors of childhood brain and skull-based tumors. Twenty-two children who had undergone treatment for brain or skull-based tumors were enrolled in a prospective study to extensively evaluate the HPA axis. Five tests of the adrenal axis were evaluated in each patient, including determination of basal serum cortisol, a standard ACTH test (250-microg i.v. bolus), a low dose ACTH test (0.2 microg/kg i.v. bolus), an insulin tolerance test, and a single dose metyrapone test. Cortisol responses to both ACTH tests were nearly identical. Two patients (9%) failed the low dose ACTH test, whereas three (14%) failed the standard ACTH test; five of the children (23%) failed the insulin tolerance test, and five (23%) had abnormal responses to metyrapone. One child who initially passed the metyrapone test failed the test 19 months later after becoming symptomatic. All children with abnormal metyrapone test results had low levels of basal cortisol secretion. In this study, the low dose ACTH test did not improve the sensitivity of ACTH testing for evaluation of the HPA axis. We conclude that a single morning basal cortisol level is a good screen for testing the HPA axis in children. We recommend confirming HPA axis dysfunction with the single dose metyrapone test, although this test also has limitations.

Assessment of hypothalamic-pituitary-adrenocortical axis function in dexamethasone treated very low birth weight infants by a single dose metyrapone test and gas chromatographic mass spectrometric determination of urinary steroids.

In order to assess hypothalamic-pituitary-adrenocortical axis function, we conducted low and single oral dose metyrapone tests (35 mg/kg) in dexamethasone treated very low birth weight infants with bronchopulmonary dysplasia (n = 12). The responses to metyrapone of tetrahydro-11-deoxycortisol (THS) and cortisol metabolites were analyzed by gas chromatography and mass spectrometry in 24-h urinary specimens. For comparative reasons, morning plasma 11-deoxy-cortisol and cortisol were measured by radioimmunoassay before and after metyrapone. No side effects of metyrapone were observed in our patients. In 5 of 12 patients, no urinary THS could be stimulated after metyrapone and most of the other patients had small increases in urinary THS. These findings suggest suppressed or strongly impaired hypothalamic-pituitary-adrenocortical axis function in most patients. While the concentrations of plasma 11-deoxycortisol showed little variation, those of plasma cortisol were grossly different from the respective urinary values. We recommend steroid analysis in 24-h urinary specimens by gas chromatography and mass spectrometry, because urinary steroids provide more information and the highly specific analytical technique is independent of phenomena such as cross reactivity or matrix effects. The low and single oral dose metyrapone test in combination with urinary steroid analysis by gas chromatography and mass spectrometry therefore provides a noninvasive, convenient and safe means of evaluating the integrity of the hypothalamic-pituitary-adrenocortical axis in very low birth weight infants.

Prednisolone metasulphobenzoate foam retention enemas suppress the hypothalamo-pituitary-adrenal axis.

Corticosteroid enemas represent effective treatment for ulcerative proctitis, but absorption into the systemic circulation may have undesirable metabolic consequences. Prednisolone metasulphobenzoate, a lipophobic corticosteroid derivative, is designed to be absorbed poorly through the recto-sigmoid mucosa, but the effects of foam enema preparations upon the hypothalamo-pituitary-adrenal axis have not been examined. Nine patients suffering from active ulcerative proctitis underwent four weeks of therapy with prednisolone metasulphobenzoate foam enemas. The hypothalamo-pituitary-adrenal axis, defined using the modified single-dose metyrapone test, glucose homeostasis and lipid profiles were studied before and after treatment. The hypothalamo-pituitary-adrenal axis was significantly depressed after the treatment period; mean stimulated plasma cortisol concentration fell from 384 +/- 244 (s.d.) to 288 +/- 252 nmol/L, P < 0.02; stimulated mean plasma 11-deoxycortisol concentration fell from 677 +/- 333 to 407 +/- 326 nmol/L, P < 0.01. Mean fasting plasma glucose, insulin, C-peptide, fructosamine and triglyceride concentration were unchanged, whilst the mean serum cholesterol concentrations rose from 5.6 +/- 1.1 to 6.0 +/- 1.2 mmol/L (not significant). Prednisolone metasulphobenzoate foam enemas have significant systemic and endocrine metabolic effects, which could assume importance with long-term therapy.

Beta-endorphin responses to metyrapone and dexamethasone in depressed patients

Controversy continues over the characteristics of beta-endorphin secretion in depression. Beta-endorphin plasma levels were measured in 30 drug-free male patients with a DSM-III-R major depressive disorder and 21 healthy controls. Depressed patients displayed significantly lower beta-endorphin plasma levels in baseline conditions, after the single dose metyrapone test, and after the dexamethasone suppression test. The activation of hypothalamic-pituitary-adrenal (HPA) axis in depression might be due, at least in part, to low levels of beta-endorphin. These results suggest that HPA axis dysregulation in depression may involve peptides other than ACTH.

Effects of metyrapone and dexamethasone on pro-gamma-MSH and ACTH levels in depressed patients

There is current controversy over the mechanisms underlying hypothalamic-pituitary-adrenal (HPA) axis hyperactivity in depression. Pro-gamma-MSH, a portion of the N-terminal region of POMC, has been shown to act synergistically with ACTH in stimulating corticosteroid secretion in vitro and in vivo. Pro-gamma-MSH and ACTH plasma levels were measured in 30 drug-free male patients with a DSM-III-R major depressive disorder and 21 healthy controls. The baseline levels were similar in the two groups. After single-dose metyrapone stimulation, both hormones increased, but pro-gamma-MSH was significantly higher in control subjects than in depressives. After overnight 1 mg dexamethasone, ACTH was significantly less suppressed in depressives than controls. These results suggest that HPA axis dysregulation in depression may involve peptides other than ACTH and be more complex than previously reported.

Effects of metyrapone and dexamethasone upon pro-gamma-MSH plasma levels in depressed patients and healthy controls

There is current controversy over the mechanisms underlying hypothalamic-pituitary-adrenal (HPA) axis hyperactivity in depression. Pro-γ-melanocyte-stimulating hormone (MSH), a portion of the N-terminal region of pro-opiomelanocortin, has been shown to act synergistically with adrenocorticotropic hormone (ACTH) in stimulating corticosteroid secretion both in vitro and in vivo. Pro-γ-MSH and ACTH plasma levels were measured in 30 drug-free male patients with a DSM-IIIR major depressive disorder and 21 healthy controls. The baseline levels were similar in the two groups. After single-dose metyrapone stimulation, both hormones increased, but pro-γ-MSH was significantly higher in control subjects than in depressives. After overnight 1-mg dexamethasone, ACTH was significantly less suppressed in depressives than controls. These results suggest that HPA axis dysregulation in depression may involve peptides other than ACTH and be more complex than previously reported.

The effect of an inhaled steroid on the hypothalamic‐pituitary‐adrenal axis‐which tests should be used?

Inhaled corticosteroids may produce systemic effects which include decreased hypothalamic-pituitary-adrenal (HPA) axis activity. Four tests of HPA axis function were assessed in 12 healthy volunteers, during inhalation of two actuations of beclomethasone dipropionate (250 micrograms) aerosol four times daily for 15 days, to determine the most appropriate test for this effect of inhaled corticosteroids. Measurement of basal adrenal activity showed that both 24-hr urinary free cortisol and 0900 hr plasma cortisol were decreased by the fourth day of steroid treatment. All 12 subjects had decreases in basal adrenal activity. Overall the 24-hr urinary free cortisol showed the greater change, with mean pre-steroid baseline values of 497 and 515 nmol/24 hr reduced to 167 nmol/24 hr on the ninth day of treatment (P less than 0.001). The single-dose metyrapone test showed marked changes in each of the six subjects tested. The mean 11-deoxycortisol response was 96 nmol/l on the eleventh day of treatment, compared to baseline and eight-day post-treatment values of 439 and 407 nmol/l respectively (P less than 0.001). In contrast, no consistent treatment-related changes were observed with the short tetracosactrin test. Only two out of six subjects had an abnormal short tetracosactrin test, although all showed a decrease in basal adrenal activity. From these results, the 24-hr urinary free cortisol and single-dose metyrapone test at 0600 hr are recommended to assess the effect of inhaled glucocorticoids on the HPA axis.(ABSTRACT TRUNCATED AT 250 WORDS)

Single-dose metyrapone test at 06.00 h: an accurate method for assessment of pituitary-adrenal reserve.

One dose of metyrapone (1.5g) administered at 06.00 h, with subsequent measurement of 11-deoxycortisol and 17-hydroxycorticosteroid (17-OHCS) levels in plasma at 12.00 and 14.00 h, allowed accurate assessment of the pituitary-adrenal reserve. Normal response was defined as achieving a serum 17-OHCS level of more than 10.0 micrograms/100 ml and a 11-deoxycortisol level of more than 6.0 micrograms/100 ml at either 12.00 or 14.00 h. These criteria are based on a group of 18 persons with normal pituitary-adrenal axis, and 86 additional cases responded in this normal range. In this group of 104 subjects, 11-deoxycortisol levels rose to 9.2 +/- 3.5 micrograms/100 ml at noon and 17-OHCS levels to 15.4 +/- 4.7 micrograms/100 ml at 14.00 h. Post-metyrapone 17-OHCS levels were significantly higher than normal cortisol levels at these times (P less than 0.001) and than those observed at 08.00 h on the day of the test, demonstrating stimulation of adrenal corticoid production in addition to blockade of cortisol production by metyrapone. Thirty-one patients found to suffer from secondary adrenal failure showed impaired response. All these patients had limited pituitary-adrenal reserve, either proven by other pituitary-adrenal tests or implicated by severe pituitary disease.

Effect of metoclopramide and L-dopa on a single dose metyrapone test in normal men.

Effect of metoclopramide and L-dopa on a single dose metyrapone test in normal men.

The Discrepancy Between ACTH and 11-Deoxycortisol Levels in a Single Dose Metyrapone Test

Five healthy men were given 1.0 gr of metyrapone p.o. (MTP test) with and without 0.5 gr of 1- dopa p.o. (DOPA-MTP test) or 10 mg of metoclopramide p.o. (MTC-MTP test) and plasma 11-deoxycortisol, cortisol, ACTH and pregnenolone (only in MTP test) were determined before and hourly after the drug administrating for 6 hrs. In the MTP test, plasma 11-deoxycortisol increased significantly at 1 hr with peak at 5 hrs, whereas the significant increases of pregnenolone and ACTH were not seen until 2 hrs, although plasma cortisol levels were reduced definitely at 1 hr. Thus, the increase of 11-deoxycortisol in the MTP test should be divided into two phases; the increase in the phase II (later than 3 hrs) is due to pituitary ACTH reserve, and that in the phase I (until 2 hrs) is due to unknown mechanism other than pituitary reserve. In the DOPA-MTP test, the 11-deoxycortisol rise was significantly larger than that in the MTP test. The increases in 11-deoxycortisol at 4 hrs and 5 hrs in the MTC-MTP test were significantly smaller than those in the MTP test. The cortisol/(cortisol + 11-deoxycortisol) ratio reached its lowest point at 3 hrs in the MTP test and at 2 hrs (a 1 hr advance) in the DOPA-MTP and MTC-MTP tests. However, there were no significant differences in the responses of cortisol and ACTH to metyrapone in these tests. This provides evidence for a discrepancy between plasma 11-deoxycortisol and ACTH responses in a single dose metyrapone test, as disclosed by the simultaneous administration of dopamine agonist or antagonist with metyrapone.

The discrepancy between plasma 11-deoxycortisol and ACTH concentrations in a single dose metyrapone test in normal men.

A single dose methyrapone test (MTP test) was carried out on 6 normal men by administering 1.0 g of metyrapone at 08.00-09.00 h with and without dexamethasone (DXM-MTP test) pre-treatment. Plasma 11-deoxycortisol, pregnenolone, ACTH and cortisol were measured before administration of the drug, and at hourly intervals for 6 h. In the MTP test, 11-deoxycortisol increased significantly at 1 h with a peak at 5 h, whereas significant increases in pregnenolone and ACTH were not seen until 3 h. There was a definite decrease in the cortisol level at 1 h with the lowest level measured at 2 h. Thus, a time discrepancy between plasma 11-deoxycortisol and ACTH concentrations was observed. The increase in 11-deoxycortisol after metyrapone should be divided into two phases: the increase in phase II (after 3 h) is due to the pituitary ACTH reserve, and that in phase I (the first 2 h) is due to some mechanism other than the pituitary ACTH reserve. The increased amount of 11-dexoycortisol in phase II (218.1 nmol) occupied 60.5% of the total increased amount in phases I and II (360.6 nmol). The cortisol/(cortisol + 11-deoxycortisol) ratio reached its lowest point 3 h after metyrapone treatment. This might be due to the initiation of an additional surge in 11-deoxycortisol by the ACTH reserve at 3 h.

Effect of cyproterone acetate on pituitary-adrenocortical function in man.

Recent literature (1973-1976) suggests suppression of pituitary-adrenal function in patients (eg with pubertas praecox) who are treated with cyproterone acetate in high doses for prolonged periods. Therefore we investigated in our metabolic ward the effects of administration of 200 mg cyproterone acetate per day during 20 days to 4 healthy male volunteers. Baseline plasma cortisol and ACTH levels, repeated diurnal plasma cortisol and ACTH profiles and the results of tetracosactide (Synacthen) stimulation tests and single-dose metyrapone (Metopiron) tests proved to be comparable before, during and after treatment. Moreover, a slight gradual increase in urinary cortisol excretion during the observation period indicated that cyproterone acetate in the given dose during 20 days certainly does not reduce the pituitary-adrenal function of 4 healthy male volunteers. Long-term administration (during 1 to 7 years) of the combination of cyproterone acetate and ethinyloestradiol did not suppress serum levels of cortisol, prolactin, thyroxine and TSH in 18 female patients with hirsutism and/or acne.

Plasma 11-deoxycortisol response to single dose metyrapone in prostatic cancer patients (author's transl)

A radioimmunoassay procedure for plasma 11-deoxycortisol (S) was developed using an antiserum prepared by immunizing rabbits with S-21-hemisuccinate bovine serum albumin and S-3-oxime-bovine serum albumin. Thereafter plasma S, cortisol (F) and adrenocorticotropic hormone (ACTH) responses to metyrapone were investigated in 13 normal adult males and 39 patients with prostatic cancer. The results were as follows: 1) The antiserum against S-3-oxime-bovine serum albumin had less cross reactivity (less than 10%) with other steroids than that against S-21-hemisuccinate bovine serum albumin and obtained a good standard curve. The intra-assay variance and interassay variance of this method using the former antiserum (N = 10) were 12.4% asd 14.9% respectively, and the blank value was 3.7 +/- 1.6 pg. 2) Basal levels of S. F and ACTH in plasma from 13 normal adult males, ranged 21 approximately 80 years, old, were 98.4 +/- 15.7 ng/dl (mean value +/- S.E.), 12.7 +/- 0.78 micrograms/dl and 30.6 +/- 3.02 pg/ml respectively. Those level increased to 7060 +/- 598 ng/dl, 24.3 +/- 1.69 micrograms/dl and 24.3 +/- 1.6 pg/ml at 9 a.m. following oral administration of metyrapone (30 mg/kg b.w.) at midnight. 3) Both basal levels and responses of plasma S and F to metyrapone increased remarkably, while those of ACTH were within the normal range in prostatic cancer patients during the estrogen therapy. It was considered that protein-bound S and F increased following elevation of corticosteroid binding globulin but returned to the normal range about 2 weeks after discontinuation of the therapy. 4) In case treated wih estrogens, plasma, S, F and AC normal range in prostatic cancer patients during the estrogen therapy. It was considered that protein-bound S and F increased following elevation of corticosteroid binding globulin but returned to the normal range about 2 weeks after discontinuation of the therapy. 4) In case treated wih estrogens, plasma, S, F and AC normal range in prostatic cancer patients during the estrogen therapy. It was considered that protein-bound S and F increased following elevation of corticosteroid binding globulin but returned to the normal range about 2 weeks after discontinuation of the therapy. 4) In case treated wih estrogens, plasma, S, F and ACTH responses to metyrapone were unchanged compared to normal adult males 2 approximately 4 weeks after discontinuation of the therapy, and this data suggested that estrogens had no inhibitory effect on the pituitary-adrenal axis. However, in cases treated with progestational agents over a long-term period, plasma S and ACTH responses to metyrapone decreased slightly but returned to the normal range 2 approximately 4 weeks after discontinuation of the therapy. This suggested that the inhibitory effect of these agents on the pituitary-adrenal axis was mild and reversible.

Short-term kinetics of serum adrenal steroids and plasma ACTH after a single dose of metyrapone in man.

The in vivo influence of metyrapone (M) on different adrenal enzymes has been studied by simultaneous measurement of serum progesterone (P), 17-hydroxyprogesterone (17-OHP), deoxycorticosterone (DOC), corticosterone (B), deoxycortisol (S), 18-hydroxydeoxycorticosterone (18-OHDOC), aldosterone and cortisol (F) as well as by the measurement of plasma ACTH before and after oral administration of 40 mg of M/kg at 08:15 in four healthy male subjects. The well known inhibitory effect of M on adrenal 11-hydroxylase is demonstrated by a decrease of serum F and B and synchronous increase of serum S and DOC after administration of M. The additional inhibition of 18-hydroxylase by M is documented by a decrease of serum 18-OHDOC in spite of a marked increase of serum DOC after M. The moderate increase of serum P and 17-OHP soon after drug administration, although plasma ACTH is highly elevated at this time, as well as the marked increase of these steroids in the afternoon synchronously to a rise of serum F and B suggest a further inhibitory effect of M on the enzyme prior to the total corticosteroid biosynthesis. This effect of M should be taken into account if ACTH activity is monitored in terms of adrenal steroid output in the metyrapone test.

Prenatal manifestation of isolated ACTH-deficiency

In a 34 yr old pregnant woman, serum(S)-HPL (3.3 ug/ml, 34 weeks)and urinary (U)-HCG (19000 IU/24 h, 28 weeks) were normal, but U-estriol (5.4, 4.5, 3.5mg/24h at 32, 33 and 34 weeks) was low without any complications. A boy (48.5 cm, 2980 g) was delivered after 38 weeks with Apgar score 9/10/10. He had neonatal hypoglycemia (31 mg/dl), muscular hypotonia, transient hyperbilirubinemia, and unilateral cryptorchidism. U-16-hydroxylated steroids and THE-response to ACTH were normal excluding placental sulfatase deficiency and congenital adrenal hypoplasia, but U-THS after a single dose of metyrapone(M, 500mg/m2) was <60μg/12h. At age 4 yrs, extreme fatigue, spells of daytime sleep, and aggressive behavior occurred 3 - 4 times a week. Plasma cortisol (F) responded to ACTH (4.0 - 20.3 μg/dl), but U-THS after M was extremely low (<10 μg/m2/12h). With severe insulin induced hypoglycemia (14 mg/dl), S-ACTH increased insufficiently (87 to 102 pg/ml, normal maximum 216-522pg/ml). GH-response to insulin and arginine and TSH response to TRH were normal, while the LH and FSH response to LHRH was low. Treatment with F (10 mg daily) resulted in disappearance of the symptoms. It is concluded that fetal ACTH-deficiency may be a cause of low maternal U-estriol.