The acute effect of metoclopramide on plasma prolactin during pregnancy.

The effect of metoclopramide on plasma prolactin levels was studied in 10 women in the second half of pregnancy. The IV injection of 10 mg metoclopramide produces a significant rise in prolactin in 15 minutes, a peak of up to 6.5-fold over basal levels at 30 minutes and a sustained significant elevation for at least 4 hours. The results of this study indicate that maternal plasma protein levels although elevated, are still under inhibitory control and that the prolactin releasing capacity of the pituitary is maintained during pregnancy. The elevated hyperprolactinemia induced by metoclopramide may be of help in investigating the role of prolactin in human pregnancy.