Prolactin-lowering effect of low doses of lisuride in man.

Lisuride, a new semisynthetic ergot derivative, effectively decreased the TRH-induced hyperprolactinaemia in healthy female volunteers at a dose of 300 microgram given orally. Basal prolactin levels were suppressed after a single dose of 100 and 200 microgram lisuride. This effect was still present 6 h after administration. Two hundred microgram lisuride also decreased the high serum prolactin levels produced by im injection of 50 mg sulpiride, and conversely, sulpiride injection abolished the prolactin lowering effect of lisuride. These results demonstrate that in man too lisuride is a very potent prolactin-lowering agent. In addition, the data support the hypothesis of a predominant role of dopaminergic mechanisms in the regulation of prolactin secretion.