Adenohypophyseal function was evaluated in 20 consecutive patients with hyperprolactinemic amenorrhea-galactorrhea in an attempt to predict ovulatory response with 2-brom-alpha-ergocryptine (CB-154) therapy. Pituitary fossa tomography and response to insulin, thyrotropin-releasing hormone, and luteinizing hormone--releasing hormone were correlated with the return of ovulatory cycles. Fourteen of 15 patients demonstrating normal pretreatment sellar volume ovulated, compared with 0 of 5 showing increased volume. Thirteen of 14 with adequate adenophypophyseal reserve of growth hormone and luteinizing hormone ovulated, compared with 0 of 6 and 1 of 6, respectively, with inadequate reserve. Serum prolactin suppression to normal occurred in 19 of 20 patients but could not predict response. Only 2 of 10 patients receiving clomiphene citrate ovulated and neither conceived, while 8 of the 10 ovulated with CB-154 and 6 of 7 desiring pregnancy conceived. CB-154 is an effective "fertility drug" and response to therapy can usually be predicted.