6-keto-prostaglandin F1 alpha/thromboxane B2 ratio in vascular and lung tissue.

In vitro production of 6-keto-PGF1 alpha and thromboxane B2 (TxB2) was determined by radioimmunoassay. The 6-keto-PGF1 alpha/TxB2 ratio varied between 5 and 41 in vascular tissue and between 0.5 and 6 in lung tissue from various species. There was a correlation between the production of 6-keto-PGF1 alpha and TxB2; the correlation coefficient being about 0.6. The production of 6-keto-PGF1 alpha and TxB2 was stimulated by arachidonic acid and inhibited by indomethacin. The 6-keto-PGF1 alpha/TxB2 ratio was increased by a thromboxane synthetase inhibitor and various peptides, e.g. DDAVP and bradykinin, and was decreased by arachidonic acid. It is suggested that the balance between 6-keto-PGF1 alpha and TxB2 production in the vessel wall could be of importance in certain pathological conditions, e.g. thrombus formation.