Identification of 6-keto-prostaglandin E1 obtained from isolated perfused kidney of the rabbit.

We studied the release of 6-keto-prostaglandin (PG) E1-like material into urinary and venous effluents of the isolated perfused kidney of the rabbit. After high performance liquid chromatographic (HPLC) separation, material coeluting with authentic 6-keto-PGE1 was measured by radioimmunoassay, platelet antiaggregation bioassay and characterized further by gas chromatography/mass spectrometry-single ion monitoring (GC/MS-SIM). Injection of either arachidonic acid or ATP into the renal artery stimulated the release of prostacyclin [measured as immunoreactive (i)-6-keto-PGF1 alpha] and i-6-keto-PGF1. HPLC fractions containing i-6-keto-PGE1, and coeluting with 6-keto-PGE1 standard, exhibited potent inhibition of platelet aggregation. The presence of authentic 6-keto-PGE1 was verified by the GC/MS-SIM spectra in HPLC zones from which radioimmunoassayable and bioassayable 6-keto-PGE1-like material was recovered.