Cortisol and Aldosterone Excretion and Plasma Cortisol Concentrations in Normal and Obese Female Subjects

Abstract

1.The 24 h urinary excretion of free cortisol and aldosterone-l8-glucuronide has been studied in twenty-three control and twenty-three grossly obese subjects by a double-isotope-dilution derivative method.2. Day-night variation of plasma and urinary cortisol has also been investigated. 3. The mean absolute steroid values were similar for the obese and non-obese subjects.4. The 24 h urinary values for free cortisol expressed as pg/kg of body weight were significantly higher for the controls.5. The majority of the obese and control subjects had a day-night variation of plasma cortisol. All subjects, with two exceptions, showed day-night variation of free cortisol in the urine.6. It is suggested that the estimation of unconjugated cortisol in timed urinary collections could be useful for investigations of adrenocortical function.7. The findings do not support the presence of increased adrenocortical activity in developed obesity.

Adrenocortical Function in Obesity and Cushing's Syndrome

“…The observation that some subjects with Cushing's syndrome may have values within the normal range confirms the studies of several other workers (Ekman et al, 1961 ;Kornel, 1969). Similarly the finding that a few subjects with Cushing's syndrome may maintain day-night variation of plasma corticosteroids, and that it may be absent in some apparently normal subjects and in cases of obesity, has been noted (Ekman et al, 1961 ;Schultz et al, 1964;McHardy-Young et al, 1967;Jackson & Mowatt, 1970;Hankin et al, 1972).…”

“…Urinary free cortisol is considered to be a sensitive gauge of cortisol production and the amount of this steroid is similar in normal and obese women (see Hankin et al, 1972, for further discussion). Elevated excretions, which are relatively consistent, have been reported for patients with Cushing's syndrome of varying aetiology (Rosner et al, 1963;Murphy, 1968).…”

“…However, in contrast to most subjects with Cushing's syndrome, the unconjugated urinary cortisol for obese subjects falls within the normal range (Rosner et al, 1963;Schteingart et al, 1963;Murphy, 1968;Streeten et al, 1969;Hankin, Theile & Steinbeck, 1972). These apparently discrepant results have been attributed (Schteingart et al, 1963;Migeon et al, 1963;Rabinowitz, 1970) to increased turnover rates for cortisol in obesity.…”

“…The methods for urine and plasma collection and storage, and measurement of urinary creatinine and unconjugated cortisol in the urine have been described previously (Hankin et al, 1972). P-S chromogens.…”

“…However, some subjects with Cushing's syndrome may maintain a normal rhythm (Schteingart et al, 1963;Ernest, 1966;Espiner, 1966) and the variation may be absent in some apparently normal subjects and some with obesity (Ekman et al, 1961;McHardy-Young et al, 1967;Jackson & Mowatt, 1970;Hankin et al, 1972).…”