Liver blood flow and volatile fatty acid utilization in sheep before and after carbon tetrachloride treatment

Liver blood flow and the net uptakes of acetate, propionate and butyrate were estimated in control and carbon tetrachloride (CCl4) treated sheep after an 18 h fast and during intra-ruminal infusion of a solution of the above volatile fatty acids (VFA). Portal venous blood flow was increased and the hepatic arterial blood flow reciprocally decreased by the VFA infusions in the control sheep and, even more so, in the CCl4-treated sheep. In the control sheep, increased hepatic availability of propionate was accompanied by increased hepatic uptake so that the propionate extraction percentage was maintained. In the CCl4-treated sheep, the propionate extraction percentage was greatly reduced when the propionate availability was increased and consequently the systemic blood concentrations of propionate were greatly elevated in these circumstances. Neither VFA infusion nor CCl4 treatment caused changes in hepatic acetate utilization. However, the systemic blood concentrations of acetate were significantly increased in the VFA-infused CCl4-treated sheep, suggesting changes in extra-splanchnic acetate utilization in this group. Increased hepatic butyrate availability was accompanied by increases in hepatic uptakes without changes in percentage extraction in both the control and CCl4-treated sheep.