RELATIONSHIP BETWEEN SERUM PSEUDOCHOLINESTERASE AND TRIGLYCERIDES IN EXPERIMENTALLY INDUCED DIABETES-MELLITUS IN RATS

This study was designed to understand the reasons for the increase in serum pseudocholinesterase activity in diabetes mellitus. Streptozotocin-induced diabetic rats were used for the study. Serum pseudocholinesterase activity increased with the induction of diabetes (381.5 units/l +/- 11.8) compared to the non-diabetic rats (243.1 units/l +/- 7.2). Serum triglycerides, total low density lipoprotein and glycerol also increased concurrently with the development of diabetes. Insulin treatment of the diabetic rats normalized serum glucose concomitant with the reduction of pseudocholinesterase activity, triglycerides, total low density lipoprotein and glycerol. Heparin injection appeared to activate lipoprotein lipase in the diabetic rats by showing a marked fall in serum triglyceride and total low density lipoprotein levels but not in pseudocholinesterase activity. Administration of tetraisopropylpyrophosphoramide a specific pseudocholinesterase inhibitor, inhibited serum and adipose tissue pseudocholinesterase activity by > 80% and liver > 50%. Concurrent with the inhibition of pseudocholinesterase activity serum triglyceride, low density lipoprotein and glycerol decreases significantly. In normal rats treatment with tetraisopropylpyrophosphoramide also reduced serum lipoproteins markedly, while glycerol only showed a marginal decrease. Glycerol was used as a marker of adipose tissue lipolysis and total low density lipoprotein which is defined as lipoproteins of density < 1.063 (LDL + VLDL). Our findings suggest (a) that the increase in serum pseudocholinesterase activity in diabetic rats is due to the overproduction of very low density lipoprotein triglyceride in the liver, and (b) decreased lipolysis in the adipose tissue of the diabetic rats treated with tetraisopropylpyrophosphoramide is accompanied by an inhibition of pseudocholinesterase activity.