Changes in Plasma Lecithin: Cholesterol Acyl Transferase Activity in Rats Fed a Cholesterol Diet.

Abstract

SummaryThe effect of feeding of cholesterol equivalent to 7.692 and 10.026 mg/kg/day on plasma lecithin: cholesterol aryl transferase activity in rats was examined. The enzyme activity was increased significantly in the cholesterol-fed rats (p <0.01) when compared with the level in the control animals fed a normal diet and was found to be dose (amount of cholesterol incorporated) dependent. The former group also showed relative significant increases in the plasma levels of cholesteryl ester and lysolecithin (p<0.05) and decreased levels of lecithin (p<0.01). Changes in free cholesterol levels were, however, not statistically significant (p>0.05) in the cholesterol-fed rats. The implications of these findings are discussed with respect to atherogenesis.Although the rate of mortality has been reduced, cardiovascular disease still remains one of the leading causes of death in developed countries. Studies in this area are mostly preventive and have focused on ways of reducing plasma cholesterol by nutritional means. Diet plays an important role in controlling blood lipids. The effect of dietary fat on blood lipids has been studied [1][2][3], but the effects on lipid-metabolizing enzymes have not been studied as such, despite the fact that these enzymes are responsible for changes in plasma lipids.Lecithin cholesterol acyl transferase (LCAT, EC 2.3.1.43) catalyzes the transfer of fatty acids from the C-2 position of lecithin to cholesterol [4]. In humans, almost all plasma cholesteryl ester is formed by the activity of this enzyme [5,6]. The enzyme has been implicated in the transport of cholesterol from peripheral tissues to the liver [6,7], and individuals devoid of this enzyme [8] show abnormal plasma lipoproteins [9]. In the absence of LCAT activity, both

Effect of soy protein on serum lipid profile and some lipid-metabolizing enzymes in cholesterol fed rats

“…Cholesterol rich diet has been demonstrated by several workers to increase serum total VLDL and LDL cholesterol as well as serum triglyceride concentrations (Berg et al, 1986;McGill, 1988;Onyeneke et al, 1991). Contrary to the expected elevation of serum total cholesterol, VLDL cholesterol, LDL cholesterol and triglyceride concentrations, the results obtained from this study show decreased total VLDL and LDL cholesterol as well as triglyceride concentrations.…”

“…The result of our present study shows that consumption of soy protein reduces to baseline levels, serum LPL and TGL activity. Earlier reports by Onyeneke et al (1991) and Ononugbu et al (1986) have demonstrated that increased LCAT activity is proatherogenic. The results obtained from this study supports this claim.…”

“…Experimental findings have indicated that modification of serum proteins by LCAT alters rates of cholesterol flux between cells and medium and results in a net loss of cholesterol from the cells accompanied by cellular cholesterol synthesis (Glomset, 1970;Glomset, 1976;Ray et al, 1980;Relimpio and Iriarte, 1981). Studies have also shown that an increased activity of LCAT is proatherogenic (Ononogbu and Okpara, 1986;Onyeneke et al, 1991).…”

Effect of Oryctes rhinoceros larva oil supplementation on serum lipid profile and inflammatory markers in mice fed a cholesterol-based diet

“…Blood was collected from the jugular vein into plain, sterile bottles for serum enzyme assays. The blood was allowed to stand for 30 min to clot and subsequently centrifuged at 3000 × g for 10 min at room temperature to separate the serum (18). The serum samples were collected by aspiration using a Pasteur pipette into sterile bijou bottles and stored frozen until required for analysis, which was performed within 72 h.…”