1. The activity of serum butyrylcholinesterase (‘pseudocholinesterase’, EC126.96.36.199) was investigated in 56 patients with type 1 diabetes mellitus, 51 patients with type 2 diabetes mellitus and 101 healthy control subjects.
2. Butyrylcholinesterase activity was significantly elevated in both type 1 (8.10 ± 3.35 units/ml) and type 2 (7.22 ± 1.95 units/ml) diabetes compared with the control subjects (4.23 ± 1.89 units/ml) (P <0.001).
3. In the patients with type 1 and type 2 diabetes, serum butyrylcholinesterase activity was correlated with log serum fasting triacylglycerol concentration (r = 0.41 and r = 0.43, respectively, P <0.001). In the type 2 population serum butyrylcholinesterase activity was also correlated with insulin sensitivity (r = −0.51, P <0.001).
4. Serum butyrylcholinesterase activity was unrelated to age, gender, serum γ-glutamyltranspeptidase activity, body mass index, or treatment for diabetes in both the diabetic populations.
5. In 37 non-diabetic patients with butyrylcholinesterase deficiency serum triacylglycerol levels were in the normal range.
6. These results are consistent with the view that butyrylcholinesterase may have a role in the altered lipoprotein metabolism in hypertriglyceridaemia associated with insulin insensitivity or insulin deficiency in diabetes mellitus.