AJP - Gastrointestinal and Liver Physiology, Vol 267, Issue 2 301-G307, Copyright © 1994 by American Physiological Society
Diet affects hepatocyte membrane composition, fluidity, and taurocholate transport in suckling rats
D. A. Novak, J. D. Carver, M. Ananthanarayanan and W. Ray
Department of Pediatrics, University of Florida College of Medicine, Gainesville 32610.
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.
