The difference in the actute metabolic change in ketone bodies between patients with insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM) was investigated in this study. The subjects employed were 7 patients with IDDM losing residual insulin secretion and 7 patients with NIDDM matched to the former patients for age, body mass index, duration of diabetes, daily insulin dosage, fasting plasma glucose and HbA_1c.
Blood samples were drawn at 3A. M. and 7A. M. on the same day, and plasma glucose, acetoacetic acid (AcAc), 3-β-hydroxybutylic acid (3-OHBA), free fatty acid (FFA), glycerol, cortisol and growth hormone (GH) concentrations were determined.
Plasma total ketone bodies (AcAc and 3-OHBA), 3-OHBA and FFA concentrations at 7A. M. were significantly higher in the patients with IDDM than in those with NIDDM (p<0.05), while there were no significant differences in any other parameters at 3A. M. between the patients with IDDM and those with NIDDM.
The ratios of 7A. M. value/3A. M. value of total ketone bodies, AcAc and 3-OHBA concentrations were also more significantly elevated in the patients with IDDM than in those with NIDDM. It was observed that the ratio of 3-OHBA was more than 2.0 in all of the patients with IDDM and less than 2.0 in all of the patients with NIDDM, the difference being significant with p<0.001. The reason why the concentration of total ketone bodies was elevated in the early morning only in the patients with IDDM but not in those with NIDDM was not certain, but it was thought that it is due to the absence of basal insulin secretion in the patients with IDDM.
These results indicate that 7A. M. value/3A. M. value ratio of plasma 3-OHBA will become one of the useful tools for differentiating IDDM from NIDDM.