Ogihara Takuo, Matsumoto Shigeki, Ohnishi Shuhei
Pharmaceutical Research Center, Mochida Pharmaceutical Co. Ltd, Shizuoka, Japan.
J Pharm Pharmacol. 2004 Jan;56(1):79-84. doi: 10.1211/0022357022386.
The characterization of the transport mechanism of progesterone, which is one of the neutral steroids in the adrenal cells, has been studied by the examination of progesterone uptake into the monolayers of SW-13 cells (a human adrenal adenocarcinoma cell line). The uptake of [(3)H]progesterone at a tracer concentration (1 nM) exhibited temperature, pH and sodium dependency. According to kinetic analysis of the concentration dependence, the uptake of progesterone involves saturable and non-saturable processes. The uptake for the saturable process, which gave K(t) values (half-saturation concentration) of 4.7 +/- 8.7 microM, was inhibited by metabolic inhibitors and amino-acid modifiers but not by endocytosis inhibitors or substrates for known transporters. The uptake of progesterone was also inhibited by several neutral steroids but not by anionic steroids. The inhibition by both beta-estradiol and estriol was competitive. The uptake of progesterone by the adrenal cells might be at least partially accounted for by a specific carrier-mediated transport mechanism generated by sodium ions and an electrochemical mechanism.
通过检测孕酮摄取进入SW - 13细胞（一种人肾上腺腺癌细胞系）单层细胞的情况，对肾上腺细胞中中性甾体之一的孕酮转运机制进行了表征研究。示踪浓度（1 nM）的[³H]孕酮摄取表现出温度、pH值和钠依赖性。根据对浓度依赖性的动力学分析，孕酮的摄取涉及可饱和和不可饱和过程。可饱和过程的摄取，其K(t)值（半饱和浓度）为4.7±8.7 microM，受到代谢抑制剂和氨基酸修饰剂的抑制，但不受内吞作用抑制剂或已知转运体底物的抑制。孕酮的摄取也受到几种中性甾体的抑制，但不受阴离子甾体的抑制。β - 雌二醇和雌三醇的抑制作用均为竞争性。肾上腺细胞对孕酮的摄取可能至少部分是由钠离子产生的特定载体介导的转运机制和电化学机制所导致的。
