Dose-dependency and reproducibility of the prolactin response to metoclopramide.
Six normal volunteers were tested to ascertain the dose-dependency and reproducibility of the prolactin response to metoclopramide. Furthermore, pretreatments with 1-dopa or cyproheptadine were performed. The same subjects also received intravenously 500 microgram TRH. The oral administration of 5 mg metoclopramide produced a significant rise in prolactin at 60 min and a maximal elevation at 90 min. The intravenous administration of 5 mg metoclopramide produced a significant increment at 15 min and a maximal prolactin level at 30 min. Peak prolactin levels following i.v. administration of the drug were greater than those after oral administration. Intravenous administration of 1 mg of metoclopramide produced a potential increment in plasma prolactin. Maximal prolactin response to 1 mg i.v. metoclopramide was similar to that found with 500 microgram i.v. TRH. Reproducibilities of prolactin response were good in all doses and modes of administration of metoclopramide. Pretreatment with 1-dopa inhibited the metoclopramide-induced prolactin response, but pretreatment with cyproheptadine did not influence the prolactin response to metoclopramide. Metoclopramide is a good and reproducible stimulator of prolactin secretion.
D000328:Adult; D003533:Cyproheptadine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007700:Kinetics; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D008787:Metoclopramide / Q000008:administration & dosage / Q000494:pharmacology*; D011388:Prolactin / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone
D003533:Cyproheptadine; D007980:Levodopa; D013973:Thyrotropin-Releasing Hormone; D011388:Prolactin; D008787:Metoclopramide