Effect of dietary fish oil on the sensitivity of hepatic lipid metabolism to regulation by insulin

The contribution of dietary fat content and type to changes in the sensitiv ity of hepatic lipid metabolism to insulin was studied in primary hepatocyt e cultures from donor rats maintained on a low-fat diet (LF), or on diets e nriched in olive oil (OO) or fish oil (FO). The higher rate of fatty acid o xidation in hepatocytes from the FO-fed group was resistant to the inhibito ry effects of insulin observed in hepatocytes from the other groups. Insuli n stimulation of fatty acid incorporation into triglyceride (TG) was also l ess pronounced in hepatocytes from the FO-fed group than in those from the GO-fed group but there was no difference in the stimulatory effect of insul in on fatty acid incorporation into phospholipid (PL) in these two groups. In the case of fatty acid incorporation into both PL and TG, hepatocytes fr om the LF group were refractory to stimulation by insulin. At each concentr ation of insulin, hepatocytes from the FO-fed group secreted less very low density lipoprotein (VLDL) TG than those from the other groups. However, th e absolute suppression of VLDL TG secretion by insulin was similar irrespec tive of the diet of the donor animals. We conclude that chronic consumption of a particuar type of dietary fat does not affect the insulin sensitivity of the major pathways of hepatic lipid metabolism in a consistent manner. Effect of dietary fish oil on the sensitivity of hepatic lipid metabolism t o regulation by insulin.