Basal serum dehydroepiandrosterone sulphate concentration does not predict the cortisol response to provocative testing.

The concentration of dehydroepiandrosterone sulphate (DHEAS) was measured in the plasma of 104 patients aged 16-78 years (48 men) undergoing routine assessment of anterior pituitary reserve. A fasting plasma sample was collected at 0900 h on the same day that either an insulin tolerance test or a glucagon stimulation test was performed. Serum cortisol, DHEAS and prolactin were measured by radioimmunoassay. DHEAS levels between 0.5 and 14 nmol/L were significantly but negatively correlated with age but there was no significant correlation with basal cortisol, maximum stimulated cortisol, the increment in cortisol or basal prolactin. The correlation of DHEAS with age was also observed when results for women were analysed separately but this did not hold for men. For male and female results separately, there was again no correlation of basal DHEAS with basal cortisol, maximum stimulated cortisol, increment of cortisol or basal prolactin. The age and sex related reference range and other factors affecting basal DHEAS concentration make it a cumbersome and unreliable measure of hypothalamic-pituitary-adrenal axis reserve.