Ovine corticotropin-releasing factor and dexamethasone responses in hyperandrogenic women

Eighteen hyperandrogenic, hirsute women received ovine corticotropin-releasing factor (CRF; 1 microgram/kg) as well as a dexamethasone (DEX) suppression test. Nine of the 18 hirsute women exhibited increased DEX sensitivity. Plasma adrenocorticotropic hormone (ACTH) responses after ovine CRF were significantly lower in the DEX-sensitive subgroup, but serum androstenedione was higher. Baseline serum androgen levels could not predict DEX responses. A significant negative correlation existed between the suppression of androgens after DEX and the increase in ACTH after ovine CRF. The suppression of androgen correlated with the ratio of the increase in androgen to the increase in ACTH after ovine CRF. We conclude that DEX sensitivity occurs frequently and cannot be predicted by levels of serum androgens. Blunted ACTH responses to ovine CRF may reflect enhanced adrenal sensitivity and altered feedback control.