With the exception of 6 beta-hydroxycortisol, the data agree with measurements of plasma cortisol and the results of adrenal function tests in showing little change in hypothalamic-pituitary-adrenal function with aging in healthy people.

Abstract. Cortisol production rate and urinary free cortisol excretion have been measured in healthy elderly women and elderly women about two weeks after upper femur fracture. Plasma cortisol was determined mid-morning, at the start of urine collection. All three variables were higher in the injured patients than in the control subjects. Urinary free cortisol excretion showed the greatest rise and was correlated with cortisol production rate in the patients. In the control subjects there was no correlation and nearly all the points fell below the regression line for the injured patients, indicating that urinary free cortisol excretion rose in relation to cortisol production rate after injury. Measurement of creatinine clearance showed that this was not due to an increased glomerular filtration rate, and a possible explanation is decreased metabolic clearance of cortisol. Plasma cortisol was not significantly correlated with either cortisol production rate or urinary free cortisol excretion.