The effects of some methyl prostaglandin derivatives on the ductus arteriosus of swine in vivo.

Three methylated analogues of prostaglandin E1 and E2 were examined for their ability to open the ductus arterious of neonatal piglets in vivo. Fifteen (S) 15 methyl prostaglandin E1 (15-Me PGE1), 15 (S) 1K methyl prostaglandin E2 (15-Me PGE2), and 16' 16' dimethyl prostaglandin E1 (16-diMe PGE1) all opened the ductus when given intravenously, intramuscularly or orally. The effects on ductal patency lasted four hours or more in many instances. Side-effects included apnea with intravenous and intramuscular dosages, and with high oral dosages of 15-Me PGE1. A transient drop in heart rate and blood pressure occurred with each dose. In one animal the ductus was kept open for 19 days with six-hourly intramuscular injections of 3 microgram/kg 15-Me PGE1. Transient sedation occurred with each dose. Death occurred on the 19th day and histological studies showed that the morphology of the ductus wall was similar to that seen in a two day old animal. These studies suggest that maintenance od ductal patency in the infant may be possible with oral administration of methyl prostaglandin derivatives.