Impact of short-term hydrocortisone intake on pituitary and adrenal function in healthy young male subjects

The aim of this study was to evaluate the impact of short-term therapeutic hydrocortisone intake on pituitary and adrenal function in healthy young male subjects. Ten physically active men received 50 mg/per day of hydrocortisone at 8:00 a.m. for 5 days. Cortisol, DHEA, and ACTH concentrations in plasma, and cortisol and DHEA concentrations in saliva were determined the week before, just before (8:00 a.m.) and 2 h after (10:00 a.m.) drug ingestion on days 1, 3, and 5 of treatment and day 1 post treatment. Hydrocortisone intake induced a significant increase in both plasma cortisol (×3) and saliva cortisol (×10) concentrations 2 h after administration. Plasma and saliva DHEA concentrations were significantly decreased, as were plasma ACTH concentrations, 2 h after administration, with an increase in the cortisol/DHEA and cortisol/ACTH ratios. However, no change in cortisol, DHEA, ACTH, cortisol/DHEA, or cortisol/ACTH was observed 24 h after the last intake during treatment or post treatment, except for a downward trend in saliva DHEA at days 3 and 5. The correlations between plasma and saliva cortisol, DHEA, and cortisol/DHEA were significant: respectively, r = 0.80, r = 0.80, and r = 0.88. Once-daily oral therapeutic administration of hydrocortisone for 5 days altered adrenal DHEA secretion by inhibiting pituitary ACTH, but this effect seemed transient without significant impairment of basal adrenal or pituitary function 24 h after administration. Given the high correlations between plasma and saliva, saliva samples may be offered as a sensitive surrogate for blood sampling to estimate adrenal and pituitary function.