Value of serum dehydroepiandrosterone sulfate assay in the evaluation of pituitary-adrenal insufficiency after pituitary adenomectomy

Abstract

The value of dehydroepiandrosterone sulfate (DHEA-S), a specific marker of adrenal androgen production, in the assessment of clinical states of hypercortisolism and hypocortisolism has been suggested. Since the way to simply test for ACTH reserve in patients (pts) with pituitary tumors after adenomectomy is not standardized, in this study serum DHEA-S concentration was measured in order to establish whether its determination might be a sensitive index of ACTH deficiency. Serum DHEA-S concentration was evaluated in 29 pts with hypothalamic-pituitary tumors (16 females, 13 males, aged 20–70 yr), 14 of whom had GH-secreting ade-nomas, 13 nonfunctioning adenomas, 1 prolactinoma and 1 craniopharyngioma. Serum DHEA-S and Cortisol (F) levels were determined both before and every day for 8 days after pituitary adenomectomy. Before surgery in all pts mean DHEA-S and F basal values were 3.57±0.42 μmol/L and 391.8±29.0 nmol/L, respectively. Eight out of 29 pts showed reduced DHEA-S levels (0.85±0.19 μmol/L), which remained lower than normal in the postsurgical period; on the contrary, F levels were reduced in only 2 and 3 cases before and after surgery, respectively. In 3 other pts DHEA-S levels were normal before surgery and then were low in the postoperative period, while serum Cortisol remained normal in all cases. In most of these patients, the finding of impaired responses to hypothalamic-pituitary-adrenal tests, together with a reduced corticosteroid urinary excretion, confirmed the existence of a secondary hy-poadrenalism and the necessity for an adequate replacement therapy.The remaining 20 pts showed normal DHEA-S and F levels both before and after adenomectomy and did not require replacement therapy. In conclusion: a) in pts operated on by pituitary adenomectomy the determination of serum DHEA-S is useful in order to recognize secondary hypoadrenalism; b) the reduction of DHEA-S levels is accompanied to either altered responsiveness to dynamic tests or low corticosteroids urinary excretion; c) the simultaneous evaluation of DHEA-S and Cortisol levels is suggested in order to early identify pts who will show a secondary hypoadrenalism.