Effects of Gamma-Linolenic Acid Supplementation on Lipid Composition of Liver Microsomal Membranes

I. Pregnant Rats Fed a Zinc-Deficient Diet and Those Fed a Balanced One

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The effect of gamma-linolenic acid supplementation on essential fatty acid metabolism has been studied in pregnant rats fed a zinc-deficient diet and in those fed a balanced one.
Gamma-linolenic acid supplementation was in the form of evening primrose oil (EPO) and the study of lipid metabolism was carried out on liver microsomes.
Pregnant rats were fed one of four diets: zinc-deficient (ZD), zinc-deficient+evening primrose oil (ZD+EPO), zinc-adequate (Control, C), and zinc-adequate+evening primrose oil (C+EPO) diets.
In females killed at day 21, just before parturition, both zinc concentration in liver and in vitro Δ⁶ desaturase activity were constant in the four groups. All products of in vivo Δ⁶ desaturation were also constant in the four groups, but the distribution between n-6 and n-3 polyunsaturated fatty acid families was strongly modified by gamma-linolenic supplementation. A significant decrease in the level of docosahexaenoic acid was observed in phospholipids of the C+EPO group, while in the ZD+EPO group there was a significant increase.
It is speculated that gamma-linolenic acid given in the diet could be involved in regulation of the deacylation-reacylation cycle.