M. Moussa et al., DIETARY ESSENTIAL FATTY-ACID DEFICIENCY DIFFERENTIALLY AFFECTS TISSUES OF RATS, The Journal of nutrition, 126(12), 1996, pp. 3040-3045
Quantitative Variations of polyunsaturated fatty acids (PUFA) were stu
died in various tissues: red blood cells (RBC), hepatic microsomes, ki
dney, skeletal muscle and heart of young rats fed either a control die
t (n = 7) or an essential fatty acid (EFA)-deficient diet (n = 7). Aft
er 4 wk, the EFA-[deficient rats had significantly lower proportions o
f (n-6) and (n-3) fatty acids in RBC, hepatic microsomes and kidney th
an the control group. Paradoxically, normal proportions of arachidonic
acid [20:4(n-6)] and 5,8,11,14,17-eicosapentaenoic acid [20:5(n-3)] w
ere retained in heart and skeletal muscle despite generally lower prop
ortions of the precursors, 18:2(n-6) and 18:3(n-3). Morever, absolute
levels of 20:4(n-6) and 20:5(n-3) in skeletal muscle of the EFA defici
ent group were significantly higher than in controls and 22:5(n-3) and
22:6(n-3) levels were comparable. This suggests that fatty acid propo
rtions alone, without any consideration of long-chain polyunsaturated
fatty acid quantities, may not reflect the (n-6) and (n-3) PUFA status
of individual tissues. This study indicates that diet-[induced change
s in the PUFA composition of RBC, which are often used in clinical inv
estigations, do not fully reflect the changes in the fatty acid compos
ition of organs, and that individual tissues respond differently to EF
A deficiency. The conservation of proportional and absolute levels of
20:5(n-3) and 20:4(n-6), and the decrease in the more unsaturated homo
logues in the heart, suggest that this organ may avidly retain 20:5(n-
3) and 20:4(n-6) in order to maintain eicosanoid production.