Determination of Urinary Unconjugated Cortisol by Glass Fiber Chromatography in the Diagnosis of Cushing's Syndrome1

The Relation Between Free Cortisol in Urine and 'Urinary Free 11-Hydroxycorticosteroids' as Measured by Fluorescence

“…However, the mean normal values reported for urinary fluorescence (about 200 fig./24 hr., De Moor et al 1962 ;Mattingly et al 1964) and for urinary cortisol (about 70/¿g./24hr. or less; Ayres, Garrod, Simpson & Tait, 1957;Cope & Black, 1959;Rosner et al 1963) suggest that the contri¬ bution of cortisol to the urinary fluorescence is usually well below 50 %. This is also likely to be so in Cushing's syndrome where values in excess of 400/tg./24 hr.…”

“…Similarly, the estimation of 17-ketosteroids and Porter-Silber chromogens in urine-both routinely used for assessing adrenal function in man-have been found to bear little relation to the 'true' grouped steroid measurements after separation by chromatography (Ernest, Hakansson, Lehmann & Sjögren, 1964). Several workers have found the measurement of free cortisol (ll/?,17a,21-trihydroxy-pregn-4-ene-3,20-dione) in urine a valuable pointer to adrenocortical activity (Cope & Black, 1959;Ross, 1960;Brooks, Dupré, Gogate, Mills & Prunty, 1963;Cost, 1963;Rosner, Cos, Biglieri, Hane & Forsham, 1963) but this estimation is more elaborate than routine tests and outside the scope of most hospital labora¬ tories. A rapid and simple means of measuring urinary 'free A4-3 keto-11-hydroxycorticosteroids ' by fluorescent techniques has recently been reported (De Moor, patients suspected of suffering from Cushing's syndrome.…”

Adrenocortical Stimulation Tests with ACTH: Developments and Changes of a Diagnostic Procedure

“…For obesity several authors have described pre dominantly normal results of ACTH tests in various modifications [5,19,57,94,104,106,129], Some investigations, however, showed that in obesity cases the excretion of 17-hydroxycorticosteroids after ACTH application was higher than in normal persons [71,97], P r e c i o et al [98] found a greater response only in those cases which had already initially an augmented excre tion. By means of the 1-hour test, we have compared 2 groups of obesity with the findings in bilateral adrenocortical hyperplasia.…”

Free Cortisol Index: A Rapid and Simple Estimation of Free Cortisol in Human Plasma1

“…The method allows the rapid processing of large numbers of samples and can he performed on 0.2 nil of plasma (J Clin Endocrinot Metah 40: 462,1975) M ETHODS currently employed in the clinical laboratory for the determination of cortisol (F) in plasma measure total (free and protein bound) unconjugated F. Approximately 90% of circulating F is bound to plasma proteins in man, mainly to Corticosteroid Binding Globulin (CBG) or Transcortin and to albumin (1)(2)(3)(4). It is, however, widely accepted that the unbound (free) rather than the protein-bound moiety is biologically active (5)(6)(7). Total plasma F is influenced by the concentration of binding proteins, particularly CBG, while free F is less dependent on such factors, being controlled within narrow limits by pituitary ACTH secretion.…”