ARTICLES

Effect of luminal constituents on vitamin K1 absorption into thoracic duct lymph

Lymphatic appearance rate of [3H] phylloquinone was studied in unanesthetized rats with cannulated bile and lymph ducts. A linear relationship (y= -44.9 + 10.2x, r=0.99) was found between the rate of the compound's infusion into the duodenum and its appearance rate in the lymph. Increasing the taurocholate infusate concentrations from 5 to 15 mM increased phylloquinone appearance rate in the lymph from 6.47 +/- 1.82 to 24.14 +/- 1.20 pmol/min (P less than .01). Varying the infusate pH from 4.35 to 8.0 did not change lymphatic appearance rate of vitamin K1 or lymphatic flow rate. Addition of short-chain fatty acid (butyrate) to the infusate enhanced the total absorption of vitamin K1 into the bile and lymph, whereas the addition of polyunsaturated fatty acids inhibited the total absorption of the vitamin. These experiments delineate some factors that modify the extrusion rate of vitamin K1 out of the enterocyte into the lymphatic circulation and add information regarding this phase of the absorptive pathway of lipids.