EN
We have demonstrated recently the formation of a biologically active metabolite of prostaglandin (PG) E₁, 13,14-dihydro-PGE₁, during intravenous infusions of PGE₁ in patients with peripheral arterial occlusive disease. We have now investigated the levels of the immediate precursor of 13,14-dihydro-PGE₁ , the biologically inactive 15-keto-13,14-dihydro-PGE₁, during intravenous administration of 20 pig, 40pig or 80 pig PGE₁ over a period of 60 min to human volunteers. It was found that levels of 15-keto-13,14- -dihydro-PGE₁, but not those of PGEx itself, increased in a dose-dependent manner. Thus, increased formation of 13,14-dihydro-PGE₁ from 15-keto- 13,14-dihydro-PGE₁ with increasing doses of PGE₁ can be expected to occur. It remains to be investigated, to which extent formation of small amounts of 13,14-dihydro-PGE₁ during intravenous infusion of PGE₁ could contribute to the therapeutic effects of PGE₁ in patients with peripheral arterial occlusive disease.