HSPG, a component of size-and charge-selective barrier of glomerular basement membrane, is one of important matrix proteins which has been known to be reduced in the kidney of diabetic patients or animals. To examine the effects of glucose and AGE on the HSPG production by cultured GEC, we cultured rat GEC on the AGE- or BSA-coated plate under normal(5mM) and high glucose.(30mM) conditions and measured the change of HSPG production by sandwich-ELISA assay and northern blot analysis at 2 days and one week incubation periods. There was no difference in proliferation between 2 different conditions of culture plate surface. We measured the relative amount of the extracted HSPC and observed significant decreases in high glucose condition at one week incubation, and particularly on the AGE-coated surface as compared to the results of BSA-coated condition, by 22% and 5%, respectively. The expression of mRNA for perlecan promoter was decreased in condition of high glucose and AGE-coated surface by 20Yo at 2 days and 61i at one week. Even in normal glucose condition, the expression of mRNA was reduced by 30Yo at one week if the plate was coated with AGE. In conclusion, both high glucose and AGE have reducing effects on the production of HSPG by GEC in vitro. Their effects seem to be additive, however, the role of AGE is greater than that of glucose, This means that the effort to inhibit AGE formation is more important than short-term glucose control for the prevention of diabetic proteinuria.