Non-enzymatic glycosylation of tissue protein in diabetes in the rat

Non-enzymatic glycosylation of tissue and haemolysate proteins has been studied in normal and diabetic rats by reduction with tritiated sodium borohydride (NaB3H4) alone or in combination with chromatography on m-aminophenylboronic acid coupled to Biogel P-6. With NaB3H4 reduction alone, there was a linear relationship between plasma glucose and tritium incorporation into haemolysate protein. However, increased non-enzymatic glycosylation of tissue protein could not be demonstrated with NaB3H4 reduction alone. Tritiated glycosylated amino acids could be selectively removed by m-aminophenylboronic acid immobilized on Biogel P-6, then eluted by acidification and the radioactivity in the acidic peak used to estimate non-enzymatic glycosylation. Using the combined techniques, an increase in non-enzymatic glycosylation was observed in heart, kidney and liver obtained from rats with diabetes of 18 weeks duration.