Phenothiazine Stimulation Test for Prolactin Reserve: The Syndrome of Isolated Prolactin Deficiency

A characteristic prolactin secretory response occurs in normal subjects treated with chlorpromazine intramuscularly. Patients with hypopituitarism were found to have deficient or absent secretion of prolactin in response to a standard chlorpromazine test. The test has been used to identify a new syndrome, an isolated deficiency of prolactin secretion in two patients with failure to lactate.