GLYCATION OF HEPATOCYTE CYTOSOLIC PROTEINS IN STREPTOZOTOCIN-INDUCED DIABETIC RATS

A role for glycation in diabetic pathology appears beyond doubt and on e of the present trends is to focus the poorly explored field of intra cellular glycation. In this work we studied the pattern of early glyca tion in hepatocyte cytosolic proteins from streptozotocin-induced diab etic rats (n=14) compared to control animals (n=8). Glycated proteins were present in the cytosol of control rats and increased three-fold a fter one mouth of diabetes, while glycated Hb and glycated plasma prot eins rose two- and three-fold, respectively. A good correlation (r=0.8 2, p<0.001) was found between glycated cytosolic proteins and glycated plasma proteins, suggesting the latter could provide an indirect indi cation of intracellular glycation. Using PBA affinity chromatography f ollowed by SDS-PAGE we detected 7 major glycated bands in cytosols fro m control animals which increased dramatically in diabetic rats. Moreo ver, other glycated proteins, which were undetectable in control anima ls, became prominent, and more than 15 major hands can thus be resolve d. No major differences in the patterns can be seen after 1, 5. or 12 months of diabetes, suggesting that early glycation in cytosolic prote ins reaches an equilibrium in a short period of one to two weeks (furt her supported by the tight correlation with glycated plasma proteins). Through comparison of the patterns obtained with an antiglucytollysin e antibody on Western blots with those of silver stained gels from the PBA eluates we present evidence that intracellular glucation is media ted by glucose but mainly by other sugars. (C) 1996 Academic Press.