Dello, C.P., Belpaire, F.M., De Rick, A.&Fraeyman, N.H. Influence of inflammation of serum concentration, molecular heterogeneity and drug binding properties of canine alpha–1–acid glycoprotein.J. vet. Pharmacol. Therap.11, 71–76.The concentration and the heterogeneity of alpha–1–acid glycoprotein (α–1–AGP) and oxprenolol binding were determined in serum of healthy dogs and dogs with inflammatory disease. In inflammation, an increase in the mean a–1–AGP concentration from 0.47 to 2.85 g/1 was accompanied by a reduction in the mean free oxprenolol fraction from 25% to 6%. α–l–AGP concentration and oxprenolol binding were inversely correlated. The heterogeneity of canine a–l–AGP remained essentially unchanged in dogs with inflammation and, in both these dogs and the controls, between five and seven forms with different isoelectric points and one single concanavalin A–reactive form were detected. It is concluded that in dogs, as in humans, oxprenolol binds to serum α–l–AGP. Changes in serum binding of oxprenolol during inflammation result from a change in the serum concentration of a–l–AGP rather th