Grundy S M
J Clin Invest. 1975 Feb;55(2):269-82. doi: 10.1172/JCI107930.
Studies were carried out on the effects of polyunsaturated fats on lipid metabolism in 11 patients with hypertriglyceridemia. During cholesterol balance studies performed in eight patients, the feeding of polyunsaturated fats, as compared with saturated fats, caused an increased excretion of endogenous neutral steroids, acidic steroids, or both in most patients. Increases in steroid excretions were marked in some patients and generally exceeded the decrement of cholesterol in the plasma compartment. The finding of a greater excretion of fecal steroids on polyunsaturated fats in hypertriglyceridemic patients contrasts to the lack of change in sterol balance previously reported for patients with familial hypercholesterolemia; however, other workers have found that polyunsaturated fats also enhance steroid excretion in normal subjects. In most of the patients, simultaneous studies were carried out on biliary lipid composition, hourly outputs of biliary lipids, and pool sizes of bile acids. In several but not all patients, fasting gallbladder bile became more lithogenic after institution of polyunsaturated fats. This increased lithogenicity was not due to a decrease in bile acid pools; in no case was the pool decreased by polyunsaturated fats. On the other hand, two patients showed an increased output of biliary cholesterol, and frequently there was an increase in fecal neutral steroids that were derived from cholesterol; thus, polyunsaturated fats may increase bile lithogenicity in some patients through mobilization of cholesterol into bile. Reductions in plasma cholesterol during the feeding of polyunsaturated fats was seen in most patients, and these changes were usually associated with a decrease in concentration of plasma triglycerides. In fact, the degree of cholesterol lowering was closely correlated with the extent of triglyceride reduction. Therefore, in hypertriglyceridimec patients polyunsaturated fats may contribute to cholesterol reduction by changing the metabolism of triglycerides or very low density lipoproteins. The findings of changes in the metabolism of cholesterol, bile acids, and triglycerides in the patients of this study suggests that polyunsaturated fats may cause a lowering of cholesterol through multiple mechanisms, and it seems unlikely that a single action can explain all the effects of these fats on the plasma lipids.
对11名高甘油三酯血症患者进行了多不饱和脂肪对脂质代谢影响的研究。在对8名患者进行的胆固醇平衡研究中，与饱和脂肪相比，大多数患者摄入多不饱和脂肪后，内源性中性类固醇、酸性类固醇或两者的排泄量增加。一些患者的类固醇排泄量显著增加，且通常超过血浆中胆固醇的减少量。高甘油三酯血症患者摄入多不饱和脂肪后粪便类固醇排泄量增加的发现，与之前报道的家族性高胆固醇血症患者固醇平衡无变化形成对比；然而，其他研究人员发现多不饱和脂肪也会增加正常受试者的类固醇排泄量。在大多数患者中，同时对胆汁脂质成分、胆汁脂质每小时输出量和胆汁酸池大小进行了研究。在部分而非所有患者中，摄入多不饱和脂肪后空腹胆囊胆汁的致石性增强。这种致石性增加并非由于胆汁酸池减少；在任何情况下，多不饱和脂肪都不会使胆汁酸池减少。另一方面，两名患者胆汁胆固醇输出量增加，且粪便中源自胆固醇的中性类固醇经常增加；因此，多不饱和脂肪可能通过将胆固醇转运到胆汁中，增加部分患者的胆汁致石性。大多数患者在摄入多不饱和脂肪期间血浆胆固醇降低，这些变化通常与血浆甘油三酯浓度降低有关。事实上，胆固醇降低的程度与甘油三酯降低的程度密切相关。因此，在高甘油三酯血症患者中，多不饱和脂肪可能通过改变甘油三酯或极低密度脂蛋白的代谢来促进胆固醇降低。本研究中患者胆固醇、胆汁酸和甘油三酯代谢变化的发现表明，多不饱和脂肪可能通过多种机制导致胆固醇降低，单一作用似乎不太可能解释这些脂肪对血浆脂质的所有影响。
