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.

Assessment of 11beta-hydroxylase activity with plasma corticosterone, deoxycorticosterone, cortisol, and deoxycortisol: role of ACTH and angiotensin.

UNLABELLED: In this study we evaluated the role of ACTH and angiotensin on regulation of activities of 11beta-hydroxylases of the adrenal cortex. The ratio of the plasma concentrations of 11 deoxycorticosterone (DOC) to plasma corticosterone (B) reflected the activity of the enzyme of the B and/or aldosterone pathways, and the ratio of plasma 11-deoxycortisol (S) to plasma cortisol (F) as the activity of the enzyme in the F pathway. In normal subjects, both ratios were significantly lower at 0800-0900 h (Doc to B, .01+/-.004, mean+/-SE, n=10; and S to F, .01+/-.003) than at 2000 h (DOC to B, .028+/-.024 and S to F, .015+/-.005). The plasma levels of DOC, B, S and F were all significantly lower at 2000-2100 h than at 0800-0900 h. In contrast 9 patients with Cushing's syndrome exhibited no diurnal change in the ratios. The ratios increased substantially following dexamethasone or metyrapone administration. A high or low salt diet and an angiotensin infusion produced no significant effect on the ratios. The plasma concentration of all four steroids was increased by more than 50% by an infusion of angiotensin. Four hours after administration of 80 mg of Lasix at 0800 h to 10 normal subjects, the ratios of DOC to B and S to F increased significantly (P less than .02), an effect possibly related to a decreased secretion of ACTH. CONCLUSIONS: 1) 11beta-hydroxylase activity of the B and/or aldosterone and F pathways appears to change in parallel with ACTH secretion, and 2) although angiotensin stimulates steroidogenesis of the pathways, it has no apparent effect on 11beta-hydroxylase activity.

Assessment of long-acting synthetic corticotrophin in hypersensitive asthmatics and normal subjects.

The synthetic polypeptide depot-tetracosactrin (Synacthen-Depot) was given to nine steroid-treated asthmatic patients hypersensitive to animal corticotrophin. Eight had a satisfactory increase in plasma and urinary 17-hydroxycorticosteroids (17-OHCS). The remaining patient had been shown previously to have adrenal suppression. None of the patients developed allergic reactions to depot-tetracosactrin, and seven have been receiving regular injections of the polypeptide twice weekly for the past eight months.In 13 normal subjects intramuscular injections of 1 mg. and 0.5 mg. of depot-tetracosactrin and 40 units of corticotrophin-gel were equally potent in raising the plasma 17-OHCS, but depot-tetracosactrin had a significantly longer action than corticotrophin-gel.