Effects of domperidone on the secretion of prolactin from rat anterior pituitary glands

Abstract

The effects of domperidone on prolactin secretion from the anterior pituitary glands of female rats were studied. A perifusion system and radioimmunoassay were used to study secretion; static incubations and incorporation of [³H]leucine were used to measure biosynthesis. During perifusion, intact anterior lobes showed a constant rate of prolactin secretion for up to 5 h (after a 90-min preincubation to stabilize the tissue). Incorporation studies revealed an increase in protein synthesis in perifused hemipituitary glands. When glands were treated with 10 nm-domperidone, prolactin secretion began to decline after the first hour, reaching a maximum of 40–50% inhibition after a further 90 min. Growth hormone secretion showed no such decline. Inhibition of prolactin secretion continued for up to 2 h after withdrawal of the drug. Treatment with 100 nm-dopamine resulted in a more rapid inhibition of secretion, but the effect was reversed on withdrawal of the catecholamine. The prolactin content of perifused hemipituitary glands was measured after treatment with domperidone; the contents of control and treated glands did not differ, but were depleted compared with hemipituitary glands which had not been perifused.