Alterations in adrenal steroid production have been suggested in females with rheumatoid arthritis (RA). The aim of the present study was to assess adrenocortical function in RA females. We examined 11 female RA patients (RA: age 30 +/- 2 years, BMI 21.0 +/- 0.7 kg/m(2)) and 10 matched healthy controls (C: age 31 +/- 1 years, BMI 21.6 +/- 0.6 kg/m(2)). Low-dose adrenocorticotropic hormone (ACTH) test (i.v. bolus of 1 microg synthetic ACTH) was performed at 10.00 h with blood sampling every 15 min for 90 min. Cortisol, 17-OH-progesterone (17OHP), androstenedione (ASD), and dehydroepiandrosterone (DHEA) were assayed in plasma. Baseline cortisol levels were higher in RA patients (RA: 385 +/- 38 versus C: 229 +/- 28 nmol/L, P= 0.007). In both study groups, ACTH administration increased all the four steroids measured (P < 0.001). Cortisol response to ACTH administration was diminished in RA patients when compared to controls (Delta(max): 284 +/- 24 in RA versus 424 +/- 31 nmol/L in C, P= 0.002). ACTH-induced maximal rise in plasma DHEA was significantly lower in RA patients when compared to controls (Delta(max): 2.59 +/- 0.68 in RA versus 5.57 +/- 1.25 ng/mL in C, P= 0.015). No significant between-groups differences were found in responses of ASD or 17OHP. The molar ratio of ASD:cortisol was significantly lower (P < 0.05) in RA patients at base line, but did not differ during ACTH test. After ACTH bolus, the cortisol:17OHP ratio decreased significantly in the RA group (P < 0.001), whereas there was no change in the control group. The present results show decreased secretion of cortisol and DHEA in RA patients in response to ACTH, suggesting a subtle HPA hypofunction at the adrenocortical level.