Biliary phospholipid secretion is not required for intestinal absorption and plasma status of linoleic acid in mice

Biliary phospholipids have been hypothesized to be important for essential fatty acid homeostasis. We tested this hypothesis by investigating the inte stinal absorption and the status of linoleic acid in mdr2 Pgp-deficient mic e which secrete phospholipid-free bile. In mice homozygous (-/-) for disrup tion of the mdr2 gene and wild-type (+/+) mice, dietary linoleic acid absor ption was determined by 72 h balance techniques. After enteral administrati on, [C-13]-linoleic acid absorption was determined by measuring [C-13]-lino leic acid concentrations in feces and in plasma. The status of linoleic aci d was determined in plasma and in liver by calculating the molar percentage of linoleic acid and the triene:tetraene ratio. Although plasma concentrat ion of [C-13]-linoleic acid at 2 h after enteral administration was signifi cantly lower in (-/-) compared to (+/+) mice (P less than or equal to 0.05) , net intestinal absorption of dietary linoleic acid or of [C-13]-linoleic acid was similar in (+/+) and (-/-) mice. Molar percentage of linoleic acid and the triene:tetraene ratio were not different in whole plasma or in liv er of (-/-) compared to (+/+) mice. Present data indicate that biliary phos pholipids are involved in the rate of appearance in plasma of enterally adm inistered linoleic acid, but are not required for net intestinal absorption or plasma status of linoleic acid. (C) 1999 Elsevier Science B.V. All righ ts reserved.