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RESEARCH PRODUCT

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

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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.The effect of bromocriptine-induced hypoprolactinemia on peripheral androgen metabolism was investigated in 12 patients with advanced prostatic carcinoma by injecting tritiated testosterone under conditions which allowed each individual to be his own control. Prolactin was significantly (P .001) suppressed for 5 days, and after this 5-day suppression, elimination of label 1 hour after testosterone injection was about 45% and equal to prebromocriptine values. Recovery of dihydrotestosterone separated by thin-layer chromatography, however, was significantly augmented (P .005), resulting in a marked decrease of the testosterone/dihydrotestosterone ratio from 12.2-6.3. This induced 5 alpha reductase activity after prolactin suppression was expected based on earlier findings in prostate carcinoma tissue and matches well with observations of other authors on induced hyperprolactinemia. The intraprostatic and peripheral interference of peripheral serum prolactin with the 5 alpha reductase enzyme system may be a new approach to the understanding of androgen-dependent disorders such as prostatic carcinoma, and may be of paramount importance in altering the androgen environment of these patients.