Journal of Lipid Research, Vol 33, 263-271, Copyright © 1992 by Lipid Research, Inc.
Dependence on dietary cholesterol for n-3 polyunsaturated fatty acid- induced changes in plasma cholesterol in the Syrian hamster
ME Surette, J Whelan, GP Lu, KS Broughton and JE Kinsella
Lipids Research Laboratory, Cornell University, Ithaca, NY 14853.
Male Syrian hamsters consumed diets containing incremental increases in
dietary n-3 fatty acids from fish oil with either low (0.015% w/w) or
moderate (0.1% w/w) dietary cholesterol content. Animals consuming diets
containing moderate cholesterol, but not animals consuming diets containing
low cholesterol, had increased plasma very low (VLDL)- and low density
lipoprotein (LDL)-cholesterol levels with increasing fish oil consumption.
The plasma concentration of high density lipoprotein (HDL)-cholesterol
decreased by 43 and 32% with the consumption of the highest fish oil diets
in the low and moderate dietary cholesterol groups, respectively. Hepatic
LDL-receptor binding activity did not change with the consumption of low
cholesterol diets, but gradually decreased with fish oil consumption in
animals consuming the moderate cholesterol diets. Hepatic LDL-receptor
binding and plasma LDL- cholesterol levels of the different dietary fish
oil groups were highly correlated (r = -0.91). Fish oil consumption also
caused an increase in hepatic free cholesterol but a decreased cholesteryl
ester content. Therefore, in the Syrian hamster, the consumption of n-3
fatty acids increases LDL-cholesterol levels which can be partially
explained by decreased hepatic LDL-receptor binding and this response to
dietary n-3 fatty acids is dependent on the dietary cholesterol content.
However, the effects of dietary n-3 fatty acids on HDL-cholesterol are
independent of dietary cholesterol content.