1. The effects of local infusions of prostaglandins (PG) A1, A2, B1, E2 and F2α have been studied in the forearm arterial bed and superficial hand veins of man.
2. Prostaglandins A1, A2, B1, E2 and F2α all gave rise to a dose-dependent increase in forearm blood flow when infused into the brachial artery. At dosages just below the dilator range, PGF2α caused a transient fall in forearm flow, but this was not seen with any of the other prostaglandins.
3. Prostaglandins A1, A2 and E2 had no effect when infused locally into relaxed veins but caused dose-dependent dilatation when given into veins preconstricted with either noradrenaline or 5-hydroxytryptamine. Prostaglandins B1 and F2α caused dose-dependent constriction when given into relaxed veins and had no dilator effect when infused into preconstricted veins.
4. The results suggest that there are at least two types of receptors mediating responses to prostaglandins in peripheral blood vessels.