초록
식이지방의 수준에 따라 n6 와 n3 불포화지방산이 혈장 지질조성에 미치는 영향과 또 그 기전이 다른지를 연구하고자 Sprague Dawley 종 수컷쥐에게 저지방(LF, 10% Cal)식이와 고지방식이(HF, 40% Cal)를 각각 6주동안 투여하였으며, 사용된 기름은 포화지방산 급원으로는 쇠기름, n6 linoleic acid(LA) 급원으로 corn oil, n3 ${\alpha}-linolenic$ acid(LL) 급원으로 perilla oil, n3 eicosapentaenoic acid(EPA)와 docosahexaenoic acid(DHA) 급원으로 fish oil이었다. Ultracentrifugation 방법으로 VLDL fraction을 분리하여 thin layer chromatography에 의해서 화학적조성을 구하였다. Plasma cholestere 수준은 LF 와 HF 모두 n6 LA에 의해서는 오히려 증가되었고 n3 LL과 n3 EPA에 의해서는 감소되었으며, HF 에서 n3 EPA가 가장 cholesterol 저하효과가 있었다. HDL-Chol 농도는 n6 LA에 의해서 증가되었으나, HF 경우 n3 EPA에 의해서 유의성있게 감소되었다. Plasma TG 농도는 n3 EPA에 의해서 가장 감소되었고 간의 lipogenic enzyme 활성을 억제하였으며 VLDL fraction의 TG상대적양(%)이 유의성 있게 낮아졌다. 이때 LF 군에서는VLDL fraction의 apo-B의 상대적양(%)이 감소되지 않았으나 HF군에서 n3 EPA에 의해서 유의성 있게 낮았다. 그러므로 n3 EPA의 hvpotriglyceridemic effect는 간에서 lipogenesis를 억제하여 plasma VLDL로 TG 분비가 억제되었을 것이며, HF일 경우는 간에서 apo-B 생성도 억제되었다. 관상동맥성심장질환의 예방적 차원에서 평상시에도 쇠기름과 corn oil 보다는 n3 PUFA가 풍부한 들기름이나 생선을 더욱 이용하는 것이 바람직하다.
To compare the hypolipidemic effects of n6 and n3 PUFA at different fat levels, male Sprague Dawley rats were fed either low fat (LF, 10% Cal) or high fat (HF, 40% Cal) diet which was different only in fatty acid composition for 6 weeks. Dietary fats were beef tallow, corn oil, perilla oil, and fish oil concentrate as a source of saturated fatty acid, n6 linoleic acid(LA). n3 ${\alpha}-linolenic$ acid(LL) and n3 eicosapentaenoic acid(EPA)+docosahexaenoic acid(DHA), respectively. VLDL fraction was separated by ultracentrifugation and chemical composition was determined by thin layer chromatography. Plasma cholesterol level was increased by n6 LA but decreased by n3 LL and n3 EPA in LF and HF diets, and the hypocholesterolemic effect of n3 EPA was most significant in HF diet. HDL-Chol level was raised by n6 LA in LF and HF diets, but significantly reduced by n3 EPA in HF. Plasma TG level was reduced by n6 LA n3 LL and EPA in LF and HF with the reduction of lipogenic enzyme activity only by n3 PUFAs. The proportion of TG in VLDL fraction was significantly lowered by n3 EPA in LF and HF. The proportion of apo-B in VLDL fraction was not changed in LF, but was significantly decreased in HF by n3 EPA. Therefore, the hypotriglyceridemic effect of n3 PUFA could be from the reduced lipogenesis in liver and resulted in the depressed secretion of TG as VLDL in LF and HF with significant lower production of apoB in HF diet.