Partitioning of selected estrogenic compounds between synthetic membrane vesicles and water: effects of lipid components.
Partitioning of selected estrogenic compounds between synthetic membrane vesicles and water: effects of lipid components.
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DOI：
10.1021/es034311w
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发表时间：
2004-02
影响因子：
11.4
通讯作者：
Hiroshi Yamamoto;H. Liljestrand
中科院分区：
文献类型：
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作者：
Hiroshi Yamamoto;H. Liljestrand
甾体雌激素17 -雌二醇、雌三醇、雌酮和17 -乙炔雌二醇以及工业雌激素化合物对壬基酚、对叔辛基酚、双酚A、邻苯二甲酸丁苄酯和邻苯二甲酸二丁酯在脂质体膜囊泡和水之间的分配系数（K（lipw）值）采用平衡透析法测定。这些化合物的logk （lipw）和logk （low）之间的R2值低至0.679，呈中度线性相关。制备膜泡所用的脂质组分对17 -雌二醇和对壬基酚分配的影响也进行了评价。对于这两种情况，由较短酰基链组成的磷脂（如二酰酰磷脂酰胆碱）制备的囊泡的K（lipw）值都大于由较长酰基链组成的磷脂（如二硬脂酰磷脂酰胆碱）制备的囊泡。含有不饱和酰基链的磷脂（如二酰基-磷脂酰胆碱）制备的囊泡的分配系数高于仅含有饱和酰基链的磷脂（如二硬脂酰-磷脂酰胆碱）制备的囊泡。较短的酰基链和双键使脂质双分子层的液晶相构象比凝胶相构象更流畅，分配更大。相反，较高的胆固醇含量降低了分配系数。脂质双分子层空隙中胆固醇的存在可能导致双分子层的稳定和17 -雌二醇或对壬基酚分子分配的减少。这些结果表明，在选择脂质成分以评估这些化合物的生物浓度时，相变是至关重要的。
Partition coefficients of the steroid estrogens 17beta-estradiol, estriol, estrone, and 17alpha-ethynylestradiol and the industrial estrogenic compounds p-nonylphenol, p-(tert)octylphenol, bisphenol A, butylbenzylphthalate, and dibutylphthalate between liposome membrane vesicles and water (K(lipw) values) were determined using equilibrium dialysis. A moderate linear correlation with R2 values of as low as 0.679 were found for the relationship between log K(lipw) and log K(ow) for these compounds. Effects of lipid components used to prepare the membrane vesicles on the partitioning of 17beta-estradiol and p-nonylphenol were also evaluated. For both, K(lipw) values were larger for the vesicles prepared from phospholipids composed of shorter acyl chains such as dilauroyl-phosphatidylcholine than those composed of longer acyl chains such as distearoylphosphatidylcholine. Partition coefficients were higher for the vesicles prepared from phospholipids including unsaturated acyl chains such as dioleoyl-phosphatidylcholine than those solely composed of saturated acyl chains such as distearoyl-phosphatidylcholine. Both shorter acyl chains and double bonds resulted in a more fluid conformation of the lipid bilayer with the liquid crystalline phase rather than the gel phase and greater partitioning. In contrast, higher cholesterol contents reduced the partitioning coefficient. The presence of cholesterol in the void of the lipid bilayer possibly led to the stabilization of the bilayer and the decrease in the partitioning of 17beta-estradiol or p-nonylphenol molecules. These results suggest that phase transition is of critical importance in selecting lipid components to evaluate the bioconcentration for these compounds.