ABSENCE OF ALBUMIN IN THE PLASMA OF THE COMMON CARP CYPRINUS-CARPIO -BINDING OF FATTY-ACIDS TO HIGH-DENSITY-LIPOPROTEIN

It was investigated whether an albumin-like protein, active in the tra nsport of free fatty acids, is present in the blood of the common carp , Cyprinus carpio. In contrast with the brown trout Salmo trutta, no f ree fatty acid-binding protein could be found with a molecular mass an d isoelectric point similar to human serum albumin. On the other hand, free fatty acids bound in this fish species to the apolipoproteins of high density lipoprotein (HDL), namely apolipoprotein A-I and apolipo protein A-IT. In addition to the binding of free fatty acids, carp HDL was also capable of interacting with the lipophilic human serum album in binding dye, Cibracon Blue. The results obtained with plasma of car p, trout and man suggest that HDL acts as an alternative carrier for t he transport of free fatty acids in the blood when albumin concentrati ons are low or absent.