An initial exposure to high concentrations of free fatty acid increased the transfer of albumin across cultured endothelial monolayers. The rate and amount of albumin transfer was dependent on the oleic acid concentration to which the cultures were initially exposed, with 300 microM producing the maximum transfer. The albumin transfer also increased with the increasing time of exposure to oleic acid, the maximum effect occurring during the first 24 hours. An exposure to 300 microM linoleic acid produced an even greater increase in albumin transfer than did 300 microM oleic acid. The increased albumin transfer observed when cells were exposed to high concentrations of free fatty acid was largely reversible after reincubation of the cell monolayers in free fatty acid-poor media. In parallel experiments, radioactive oleic acid incorporation into cell triglycerides increased linearly as the fatty acid concentration was raised, with cell triglyceride content increasing up to sevenfold after incubation in a med...