Effect of dihydroergokryptine administration on serum prolactin and growth hormone levels in normal, hyperprolactinaemic and acromegalic subjects: evidence of potent and long-lasting pituitary dopamine receptor stimulation.

The endocrine effects of a relatively potent dopaminergic agent, dihydroergokryptine, have been studied in normal subjects, and in hyperprolactinaemic and acromegalic patients. A single 6 mg oral dose of the drug caused a marked, long lasting fall in prolactin (PRL) plasma levels in healthy subjects, in hyperprolactinaemic patients and in normoprolactinaemic acromegalics. Growth hormone (GH) levels decreased in 1-DOPA - responder, acromegalic patients, but dihydroergokryptine did not affect GH levels in normal volunteers or in 1-DOPA non-responder, acromegalic patients. The PRL- and GH- lowering activity of 6 mg dihydroergokryptine was significantly greater than that of 6 mg dihydroergocristine, and was similar to that of an oral dose of 500 mg 1-DOPA.