Alterations of peripheral testosterone matabolism after induced hypoprolactinemia in patients with prostatic carcinoma

In 12 patients with advanced prostatic carcinoma the effect of bromocriptine-induced hypoprolactinemia on the peripheral androgen metabolism was investigated after 3H-testosterone injection under conditions that each individual served as his own control. After a 5-day significant prolactin suppression, the elimination of 3H-label 1 h after testosterone injection was about 45% and equal to pre-bromocriptine values. The recovery of dihydrotestosterone separated by silica gel T.L.C., however, was significantly augmented, resulting in a marked decrease of the testosterone/dihydrotestosterone ratio from 12.2 to 6.3. This induced 5alpha-reductase activity after prolactin suppression is in accordance with our earlier findings on prostatic carcinoma tissue, matches well with observations of Magrini et al. on induced hyperprolactinemia and may be a new approach to the understanding of androgen dependent disorders.