Betaine increases the butyrylcholinesterase activity in rat plasma.

The physiological function of butyrylcholinesterase (EC 3.1.1.8, BChE) is not clearly understood, but a role was suggested in the fat utilization process, resulting in positive correlation between plasma triglyceride (TG) levels and BChE activity. Consequently we tested the hypothesis that regular intake of betaine, a natural compound intervening in the liver TG metabolism could influence the BChE activity. The BChE activity was estimated spectrophotometrically in plasma of rats fed with betaine enriched standard (B) or high-fat diet (HFB). The results confirmed decreased TG plasma levels after betaine treatment independently on the type of diet (0.15+/-0.03 (B) vs. 0.27+/-0.08 (control) mmol/l; p=0.003 and 0.13+/-0.03 (HFB) vs. 0.27+/-0.08 (control) mmol/l; p=0.005). The BChE activity increased significantly with betaine administration, however the change was more distinct in the HFB group (0.84+/-0.34 (HFB) vs. 0.22+/-0.04 (control) O.D./min/mg; p<0.001 and 0.41+/-0.11 (B) vs. 0.22+/-0.04 (control) O.D./min/mg; p=0.001). In conclusion, betaine intake led to elevated BChE activity in plasma and this effect was potentiated by the HF diet. Since betaine is in general used as a supplement in the treatment of liver diseases accompanied by TG overload, its impact on the BChE activity in the role of the liver function marker should be taken into account.

Influence of lipid imbalance on butyrylcholinesterase activity and biotransformation efficiency.

Butyrylcholinesterase (EC 3.1.1.8, BChE) is highly active in plasma, skin and lung, the tissues that first contact xenobiotics, supporting a role for BChE in detoxication of xenobiotics including medicaments. A possible involvement of BChE in lipid metabolism has been suggested. Elevated BChE activity in obese individuals correlates with some parameters of lipid metabolism including increased levels of triacylglycerols (TAG) and cholesterol. The aim of this study was to estimate the BChE activity in rats on subcellular and inter-organ levels under the conditions of untreated and treated primary hypertriacylglycerolemia with the TAG lowering agent fenofibrate. No changes in BChE activity were observed in obese animals. However fenofibrate administration led to significant increase of BChE activity in all examined tissues (plasma, liver, white adipose tissue). The impact of lipid metabolic imbalance on BChE biotransformation ability was tested by measuring the rate of hydrolysis of 0,1 to 8 mM concentrations of the antimicrobial agent N-(2-benzoyloxyethyl)-ethyldimethylammonium bromide (BCH2). The results revealed a complete shift in the BChE kinetics in all studied models. In animals with hypertriacylglycerolemia the Km value of liver BChE rised 4,6-fold, but the total enzyme efficiency expressed as Vmax/Km dropped 40% comparing to control. In contrast, in animals treated with fenofibrate the BChE efficiency increased in liver 1,6-fold. We conclude here that BChE detoxification capacity is essentially altered under conditions of disturbed lipid metabolism. Clinically, this knowledge could be important in a view of xenobiotic elimination, especially when routinely prescribed medicaments are concerned.

Enzymes cooperating in the hydrolyzing process of benzoylcholines: subcellular and inter-tissue comparison.

Within benzoylcholine biotransformation, butyrylcholinesterase (3.1.1.8, BuChE) appears to be the key enzyme in the hydrolyzing process. Except for BuChE in the process of benzoylcholine hydrolysis, carboxylesterase (3.1.1.1, CE) could play a role in the splitting of the ester bond. The aim of this work was to clarify the interaction between BuChE and CE in the hydrolyzing process of a homologic row of benzolycholines on subcellular and inter-tissue level. Two fractions, microsomes and cytosol of rabbit lung and liver were investigated. Participation of the enzyme activities was determined on the base of kinetic inhibitory studies, using eserine as cholinesterase inhibitor. Despite the fact that in all studied fractions of both organs BuChE and CE were confirmed, only in lung microsomes exclusive BuChE activity in benzoylcholine hydrolyzing process was observed, without substrate specifity. In the other fractions studied interaction of both enzymes were recorded, whereas the benzoylcholine structure played an important role. It seems that, the portion of CE depends predominantly on substrate structure and elevates with bulk of alcoholic part of benzoylcholines. Despite the same enzyme equipment in all tissue fractions studied, the affinity of hydrolyzing enzymes interestingly differs. This might be as a result of distinct subcellular pattern of CE activity localization in lung and liver.