Abstract
To establish the clinical significance of plasma free amino acids (PFAA) for protein metabolism in 31 patients with non-insulin-dependent diabetes mellitus (NIDDM), plasma concentrations of major free neutral amino acids, including valine (Val), isoleucine (Ileu), leucine (Leu), tyrosine (Tyr), phenylalanine (Phe) and methionine (Met), were examined by a new type of rapid, simplified high performance liquid chromatography.
Significant increases in branched-chain amino acids (BCAA) and Phe were observed, whereas Tyr and Met showed no alterations in patients with NIDDM compared with healthy controls. In addition, significant correlations were found between the ratio of Val +Ileu+Leu (BCAA) to Tyr+ Phe (AAA)(Fischer's ratio) and fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c). We also found that Fischer's ratios were significantly elevated in patients with poor diabetic control compared with patients with good control and healthy controls. However, after corrective therapy. Fischer's ratio was restored toward normal in parallel to improvements in FPG and HbAic levels. Furthermore, patiens with diabetic triopathy, especially diabetic nephropathy, showed a significant increase in Fischer's ratio compared with diabetic patients without complications and healthy controls.
These data suggest that Fischer's ratio may well be used as a measure of insulin-dependent alterations of protein metabolism and represents a good indicator for assessing the state of diabetic control, the course and the prognosis of patients with NIDDM, in addition to FPG and HbA1c.
