Development in immunochemical control of regulatory enzymes and receptors concerned in the lipid metabolism and the application for low-fat meat production

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The present study was conducted to identify enzymes and receptors involved in fat accumulation and to control by immunochemical methods to reduce obesity domestic animals and consequently produce "Low fat meat".1. Adipose tissue lipoprotein lipase (LPL)We could have obtained 24 positive clones of hybridoma to bind specifically with chicken LPL and 3 clones out of 24 were effective to reduce LPL activity in adipose tissues. In chickens received continuous infusion of LPL antibody (CLP-16) for 14 days, adipose fat pad weight was significantly lower than the control chickens whereas the body weight decreased to a small extent. These findings suggest that persistent administration of anti-LPL monoclonal antibody is effective mean to modify LPL activity and consequently manipulate fatness in broiler chickens.2. Adipose tissue lipoprotein receptor (LR)It was shown following western blot analysis using antiserum of various LRs (LRP, LRP380, and LR8) that LR8 was present in chicken adipose tissues and concerned in the chicken adiposity. However, administration of LR8 antibody did not modify VLDL uptake to chicken adipocytes.3. Hepatic lipoprotein receptor (HLR)It was not able to identify the new cDNA clone of chicken HLR though the screening of chicken liver cDNA library. However, new LDL binding proteins (100 and 130kDa) were detected in the ligand blot analysis in chicken liver membrane. The new LDL binding proteins were characterized by no-binding Ca ion and receptor associated protein (RAP), which were different from LDL receptor family obtained in mammals.4. Plasma cholesteryl ester transfer protein (CETP)The CETP activity in chicken plasma was high before laying eggs whereas that in laying hens was not detectable. These results suggested that chicken CETP play an important role to the cholesterol metabolism. We have been trying to obtain chicken CETP cDNA clone using human CETP probe, while at present chicken CETP cDNA sequence is still not available.