Effects of Fatty Acids and Hormones on Fatty Acid Metabolism and Gluconeogenesis in Bovine Hepatocytes

Primary cultures of hepatocytes were used to study the effects of extracellular oleate concentration and hormones on fatty acid metabolism and gluconeogenesis. Rates of oleate uptake and oxidation to acid-soluble products varied linearly as oleate concentrations increased (0.1 to 2mM), but rates of triglyceride accumulation varied quadratically. Insulin increased the proportion of oleate that was esterified by 22% without affecting the formation of acid-soluble products. Cells incubated with 2mM [1-14C] oleate for 24h eliminated 9.6% of the labeled intracellular lipid as acid-soluble products in the following 24h when no oleate was present during depletion and eliminated 7.7% when 2mM oleate was present. Insulin reduced labeled triglyceride depletion by 49%. Gluconeogenesis from [2-14C] propionate was depressed by 24%, and formation of acid-soluble products was increased by 46% in cells infiltrated with lipid because of previous exposure to 2mM oleate for 45h. Rates of gluconeogenesis from propionate were reduced 23% when 2mM oleate was present during the 3-h period that gluconeogenesis was measured, and the effect was not modified by lipid infiltration. Lipid infiltration influenced hepatic function, and insulin regulated hepatic triglyceride concentration.