Failure of metoclopramide to influence LH, FSH and TSH secretion or their responses to releasing hormones.

Intravenous metoclopramide (MET) (10 mg) induced a brisk PRL response with a mean +/- SEM peak of 85.3 +/- 7.7 ng/ml maximal at 30 min. L-Dopa, but not atropine pre-treatment, attenuated the prolactin (PRL) response to MET. This indicates that the antidopaminergic properties of MET mediate PRL secretion. MET did not influence basal levels of TSH, LH or FSH. Neither did it affect their response to the respective releasing of hormones. Our results indicate that dopaminergic blockade induced by iv MET, does not influence the secretion of the pituitary glycoprotein hormones.