Horst M A, Sastry B V
Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Prog Clin Biol Res. 1988;258:249-62.
The uptake of 14C-alpha-aminoisobutyric acid (AIB) by human placental villi from smokers and nonsmokers was measured. Washed placental villi of smokers exhibited higher uptake capacity for AIB than those of nonsmokers. The higher uptake capacity in smokers was due to increase in Vmax. Smoking increased Km and decreased affinity to AIB. This is possibly due to decreased fluidity of the plasma membrane of the villus during maternal smoking. These observations suggest that placenta utilizes its ability to increase the accumulation of amino acids during the adverse environmental conditions produced by maternal smoking.
对吸烟者和非吸烟者的人胎盘绒毛摄取¹⁴C-α-氨基异丁酸（AIB）的情况进行了测定。吸烟者洗净的胎盘绒毛对AIB的摄取能力高于非吸烟者。吸烟者较高的摄取能力归因于Vmax增加。吸烟使Km增加，对AIB的亲和力降低。这可能是由于孕期吸烟时绒毛质膜流动性降低所致。这些观察结果表明，在孕期吸烟产生的不利环境条件下，胎盘利用其能力增加氨基酸的积累。
