Effects of drugs associated with hyperprolactinemia on plasma steroids and on steroid receptors and metabolism in human breast cancer.

Certain commonly taken pharmaceutical preparations induce increased levels of plasma prolactin. The effects of these drugs on (a) tumor steroid receptors and metabolism, and (b) plasma hormones and hormone binding proteins have been studied in postmenopausal women with breast cancer. Two groups have been compared, 18 patients on drug treatment for at least 2 months and 15 subjects with no history of drug ingestion. Patients taking medication had significantly higher levels of plasma prolactin compared with control women. No significant difference was observed between the groups with regard to the plasma concentrations of dehydroepiandrosterone (DHA) and its sulphate (DHS), testosterone, estrone, estradiol-17 beta, sex hormone binding globulin (SHBG), and albumin. Similarly, no difference was observed between these two groups with regard to estrogen receptor (ER), progestogen receptor (PR), or androgen receptor (AR) levels in the tumors nor their ability to metabolize (7(-3)H) testosterone. It is considered that the ingestion of these drugs does not affect tumor mechanisms involving steroids.