Plasma prolactin (PRL) levels were measured before and 1, 2 and 4 h after oral administration of sulpiride (SPR) (2 mg/kg) in 91 healthy individuals (56 males and 35 females) and 36 patients with mental depression (15 males and 21 females). The identical measurements were conducted during remission in 16 available patients (9 males and 7 females) for comparison of the values during the depression and remission. During remission, the PRL values (lower in males and higher in females than the normal values), were closer to those of healthy subjects than they were during depression.