A rational superfusion medium for the bioassay of E-type prostaglandins on the rat stomach strip.

The optimum composition of a mixture of antagonist to be used in the bioassay of E-type prostaglandins was determined for the rat stomach strip (RSS). In the presence of atropine (10(-7)M), indomethacin (10(-6)M), propranolol (10(-4)M), and tolazoline (10(-4)M) the sensitivity of the RSS to muscarinic, alpha and beta adrenergic and serotonergic agonists was greatly reduced whereas its responsiveness to PGE1 and PGE2 was unaltered. Using the oil-immersion-superfusion technique with this drug mixture, the bioassay of prostaglandins from samples also containing other agonists gave accurate estimates of the PG concentration of the samples using small amounts of 10(-6)M PGE1 or PGE2.