Diet affects hepatocyte membrane composition, fluidity, and taurocholate transport in suckling rats

We postulated that age-related changes in hepatocyte basolateral membrane lipid composition might contribute to the diminished Na(+)-dependent taurocholate transport noted in suckling animals. Basolateral membrane vesicles (BLMVs) were prepared from suckling rats (day 11) whose dams were fed diets predominant in lard (LBLMV), corn oil (COBLMV), or fish oil (FOBLMV). Fatty acid compositions of milk and BLMV differed significantly among the groups. Membrane cholesterol was higher in FOBLMV compared with the COBLMV and LBLMV groups; lipid phosphorus and the relative distribution of phospholipid classes were similar. Fluorescence anisotropy (1,6-diphenyl-1,3,5-hexatriene) was higher in FOBLMV (0.230) than in LBLMV (0.222) or COBLMV (0.217). Excited state lifetimes were similar in all groups. Na(+)-dependent taurocholate transport was increased at 5 and 20 s in LBLMV and COBLMV compared with FOBLMV. In vitro alteration of membrane cholesterol-fluidity did not alter taurocholate transport. In conclusion, although affected by alterations in diet, simple changes in membrane fluidity-cholesterol content do not affect Na(+)-dependent taurocholate transport.