[Kinins-formation, hypotensive and oedematogen activities of four carrageenans (author's transl)].

1. The abilities of four carrageenans to form kinins in the rat plasma "in vitro" have been compared. Three carrageenans were pure: iota, kappa and lambda. The fourth sample was a mixture, made mostly of the iota type, that we called iota 2. The order of activity at the threshold level is: iota 1 = iota 2 greater than lambda greater than kappa. Kinin-formation by carrageenans is inhibited by hexadimethrine which suggests that kinin-formation depends on the activation of the Hageman factor. 2) The scale of the relative potencies of the same compounds to induce threshold hypotension when administered intravenously is the same as that for kinin-formation "in vitro". This effect is also inhibited by hexadimetrine. Crossed tachyphylaxies show that the lambda carrageenan is the most active in that respect. On this basis the order of potency is:lambda greater than iota 2 = iota 1 greater than kappa. 3) The ability to produce oedema is in the following order: lambda greater than or equal to iota 2 = iota 1 greater than kappa. The identity of the last two scales would indicate that the kinin system is of greater importance in the inflammatory process induced by carrageenans.