Effect of ergotamine on platelet prostaglandin synthesis--in vitro and in vivo experiments

We studied the effect of ergotamine on the formation of metabolites of [1 - 14C] arachidonic acid by human blood platelets incubated with ergotamine (10(-5) or 5.10(-5)M) in vitro or after 0.5 mg i.m. administration in vivo. The in vitro experiments confirmed our earlier observation that ergotamine inhibits prostaglandin synthesis. This effect, however, seemed to be restricted to the toxic dose range of the drug as in vivo it occurred only in those subjects who became nauseated or vomited after administration of the drug.