LONG-TERM INDUCTION OF AN ALDOSE REDUCTASE PROTEIN BY BASIC FIBROBLAST GROWTH-FACTOR IN RAT ASTROCYTES IN-VITRO

Basic fibroblast growth factor (bFGF) is known to elicit various devel opmental-like effects on astrocytes in vitro, but these effects were s tudied mainly over short-term periods. In this work we asked the quest ion whether bFGF could induce long-term effects on rat astrocytes in c ulture. This factor was found to induce only a transient mitogenic eff ect lasting less than 48 h, even when the treatment was carried on for 4 days. By contrast, it induced long-term effects on the rate of synt hesis of several proteins as seen by two-dimensional polyacrylamide ge l electrophoresis after labeling the cells with [S-35]methionine. The most upregulated protein was extracted from preparative gels of solubl e extracts of cultured bFGF-treated astrocytes and of normal brain. It was characterized by internal amino acid microsequencing. Two tryptic digest peptides had N-terminal sequences similar to rat lens aldose r eductase. This protein was also expressed in oligodendroglial and neur onal cells in culture, but it was not upregulated by bFGF. Aldose redu ctase is thought to be involved in a minor pathway of glucose metaboli sm and in diabetic complications. Its longterm regulation by bFGF will possibly help in the understanding of its actual physiological role.