Prolactin and growth hormone responses in the amenorrhea-galactorrhea syndrome.

Fifteen patients with hyperprolactinemia, amenorrhea, and galactorrhea were studied; 10 of these patients had apparent tumors. Nine of 12 patients had a suppression of prolactin with oral L-dopa, and all of 4 patients undergoing dopamine infusion had suppression of prolactin. Eleven and 8 patients underwent chlorpromazine stimulation and insulin-induced hypoglycemia, respectively; none responded. Three of the 4 patients did not show a growth hormone response with dopamine infusion, and L-dopa testing failed to achieve a growth hormone response in 7 of 10 patients. The data suggest an intact dopaminergic inhibition of prolactin with exogenous agents. However, inhibition of endogenous dopamine by chlorpromazine failed to elicit a prolactin response. The disordered growth hormone response to dopaminergic agents suggests a central disorder of dopamine generation. The possible implication of these results with respect to the pathogenesis of hyperprolactinemia is discussed.