TY - JOUR
T1 - The incorporation of fatty acids of different chain length into liver and biliary lipids in the perfused rat liver
AU - Rubin, Moshe
AU - Pakula, Ronit
AU - Gilat, Tuvia
AU - Tietz, Alisa
N1 - Funding Information:
This work was performed in partial fulfillment of the requirements for a Ph.D. degree of Ronit Pakula, Sackler Faculty of Medicine, Tel Aviv University, Israel. This work was partially supported by a research grant from the chief scientist, Israel Ministry of Health, Jerusalem, and Minerva Center for Cholesterol Gallstones and Lipid Metabolism in the Liver, Tel Aviv University.
PY - 1999
Y1 - 1999
N2 - In an attempt to correlate the incorporation of fatty acids (FA) of different chain length into liver and biliary lipids, isolated rat livers were perfused for 2 h with Krebs-Ringer bicarbonate containing 1% albumin and 10 μmol of [1-14C]-labeled FA: C2, C8, C10, C12, C16, and C(18:1). One to 1.36 μmol of medium-chain fatty acids (MCFA, C8, C10, and C12) and 6.6 μmol of long-chain FA (LCFA) were incorporated into liver lipids, 40% of the latter into phosphatidylcholine (PC). 14C-acetate (13 nmol) was incorporated into biliary cholesterol; 14C-MCFA contributed only 3.2-5 nmol; LCFA did not lead to newly synthesized cholesterol. Newly synthesized liver PC (2.75 to 3.25%) and newly synthesized liver cholesterol (6.5 to 10%) were secreted into bile. The specific radioactivity of biliary PC after infusion of all-saturated FA was 3.8-6.8 times higher than that of liver PC; for C(18:1) it was only 1.7-fold. The specific radioactivity of biliary cholesterol, as compared to liver cholesterol, was 12 times higher for C2 and five times higher for MCFA. This indicates that a considerable proportion of the newly synthesized lipids was secreted into bile prior to significant mixing with preexisting liver PC and cholesterol pools. Liver PC contained 8% of unchanged 14C-C12; while 14C-C10 was not detected. Biliary PC, in contrast, contained 18% of unchanged 14C-C12 and 3% 14C-C10. These results suggest that after prolonged infusion of medium-chain triacylglycerols/long-chain triacylglycerols to patients, biliary PC may become enriched with MCFA. In addition, the oxidation of these FA may provide C-2 units which increase cholesterol synthesis.
AB - In an attempt to correlate the incorporation of fatty acids (FA) of different chain length into liver and biliary lipids, isolated rat livers were perfused for 2 h with Krebs-Ringer bicarbonate containing 1% albumin and 10 μmol of [1-14C]-labeled FA: C2, C8, C10, C12, C16, and C(18:1). One to 1.36 μmol of medium-chain fatty acids (MCFA, C8, C10, and C12) and 6.6 μmol of long-chain FA (LCFA) were incorporated into liver lipids, 40% of the latter into phosphatidylcholine (PC). 14C-acetate (13 nmol) was incorporated into biliary cholesterol; 14C-MCFA contributed only 3.2-5 nmol; LCFA did not lead to newly synthesized cholesterol. Newly synthesized liver PC (2.75 to 3.25%) and newly synthesized liver cholesterol (6.5 to 10%) were secreted into bile. The specific radioactivity of biliary PC after infusion of all-saturated FA was 3.8-6.8 times higher than that of liver PC; for C(18:1) it was only 1.7-fold. The specific radioactivity of biliary cholesterol, as compared to liver cholesterol, was 12 times higher for C2 and five times higher for MCFA. This indicates that a considerable proportion of the newly synthesized lipids was secreted into bile prior to significant mixing with preexisting liver PC and cholesterol pools. Liver PC contained 8% of unchanged 14C-C12; while 14C-C10 was not detected. Biliary PC, in contrast, contained 18% of unchanged 14C-C12 and 3% 14C-C10. These results suggest that after prolonged infusion of medium-chain triacylglycerols/long-chain triacylglycerols to patients, biliary PC may become enriched with MCFA. In addition, the oxidation of these FA may provide C-2 units which increase cholesterol synthesis.
UR - http://www.scopus.com/inward/record.url?scp=0032970667&partnerID=8YFLogxK
U2 - 10.1007/s11745-999-0400-x
DO - 10.1007/s11745-999-0400-x
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AN - SCOPUS:0032970667
SN - 0024-4201
VL - 34
SP - 571
EP - 578
JO - Lipids
JF - Lipids
IS - 6
ER -