Wright R S, Anderson J W, Bridges S R
Metabolic Research Group, VA Medical Center, Lexington, Kentucky.
Proc Soc Exp Biol Med. 1990 Oct;195(1):26-9. doi: 10.3181/00379727-195-43113.
Oat bran lowers serum cholesterol in animals and humans. Propionate, a short-chain fatty acid produced by colonic bacterial fermentation of soluble fiber, is a potential mediator of this action. We tested the effect of propionate on hepatocyte lipid synthesis in rats using [1-14C]acetate, 3H2O, and [2-14C]mevalonate as precursors. Propionate produced a statistically significant inhibition of cholesterol biosynthesis from [1-14C]acetate at a concentration of 1.0 mM and from 3H2O and [2-14C]mevalonate at concentrations of 2.5 mM. Propionate also produced a significant inhibition of fatty acid biosynthesis at concentrations of 2.5 mM using [1-14C]acetate as a precursor. The demonstration of propionate-mediated inhibition of cholesterol and fatty acid biosynthesis at these concentrations suggests that propionate may inhibit cholesterol and fatty acid biosynthesis in vivo and may mediate in part the hypolipidemic effects of soluble dietary fiber. Further studies are needed to clarify this action of propionate and to establish the exact mechanisms by which the inhibition occurs.
燕麦麸能降低动物和人类的血清胆固醇。丙酸盐是可溶性纤维经结肠细菌发酵产生的一种短链脂肪酸，可能是这一作用的介质。我们以[1-14C]乙酸盐、3H2O和[2-14C]甲羟戊酸作为前体，测试了丙酸盐对大鼠肝细胞脂质合成的影响。丙酸盐在浓度为1.0 mM时对[1-14C]乙酸盐合成胆固醇有统计学显著抑制作用，在浓度为2.5 mM时对3H2O和[2-14C]甲羟戊酸合成胆固醇有显著抑制作用。丙酸盐在浓度为2.5 mM时，以[1-14C]乙酸盐作为前体，对脂肪酸合成也有显著抑制作用。在这些浓度下丙酸盐介导的胆固醇和脂肪酸合成抑制作用表明，丙酸盐可能在体内抑制胆固醇和脂肪酸合成，并且可能部分介导可溶性膳食纤维的降血脂作用。需要进一步研究来阐明丙酸盐的这一作用，并确定抑制作用发生的确切机制。
