Bile diversion in rats leads to a decreased plasma concentration of linoleic acid which is not due to decreased net intestinal absorption of dietary linoleic acid

Decreased bile secretion into the intestine has been associated with low pl asma concentrations of essential fatty acids (EFA) in humans. We studied th e mechanism behind this relationship by determining the status and absorpti on of the major dietary EFA, linoleic acid (LA), in control and 1-week bile -diverted rats. The absorption of LA was quantified by a balance method and by measuring plasma concentrations of [C-13]LA after its intraduodenal adm inistration. Absolute and relative concentrations of LA in plasma were decr eased in bile-diverted rats (P < 0.01 and P < 0.001, respectively). Fecal e xcretion of LA was increased at least 20-fold in bile-diverted rats (0.72 /- 0.11 vs. 0.03 +/- 0.00 mmol/day; P < 0.0001). Due to increased chow inge stion by bile-diverted rats, net intestinal absorption of LA was similar be tween bile-diverted and control rats (1.96+/-0.14 vs. 1.91+/-0.07 mmol/day, respectively; P>0.05). After intraduodenal administration of [C-13]LA, pla sma concentrations were approximately 3-4-fold lower in bile-diverted rats for at least 6 h (P < 0.001). Plasma concentrations of both [C-12]arachidon ic acid and [C-13]arachidonic acid were increased in bile-diverted rats (P < 0.05). We conclude that decreased plasma concentrations of LA in 1-week b ile-diverted rats are not due to decreased net intestinal absorption of LA, but may be related to increased metabolism of LA. (C) 1999 Elsevier Scienc e B.V. All rights reserved.