Mokrushnikov Pavel V, Panin Lev E, Zaitsev Boris N
FSBI Research Institute of Biochemistry SD RAMS, Novosibirsk, 630117, Russia.
Gen Physiol Biophys. 2015 Jul;34(3):311-21. doi: 10.4149/gpb_2014041. Epub 2015 Mar 2.
The action of a mixture of hormones (cortisol and adrenaline) on erythrocyte membrane during their binding was investigated. Changes in the membrane structure were elucidated by atomic force microscopy; microviscosity of the lipid bilayer and changes in the activity of Na(+),K(+)-ATPase at different concentrations of the hormones in erythrocyte suspension were estimated by the fluorescence method. Cortisol and adrenaline were shown to compete for the binding sites. A hormone that managed to bind nonspecifically to the membrane hindered the binding of another hormone. In a mixture of these hormones, cortisol won a competition for the binding sites; therewith, microviscosity of the membranes increased by 25%, which corresponds to a change in microviscosity produced by the action of cortisol alone. The competitive relationships affected also the Na(+),K(+)-ATPase activity, which was indicated by appearance of the second maximum of enzyme activity. It is assumed that an increase in microviscosity of erythrocyte membrane first raises the Na(+),K(+)-ATPase activity due to a growth of the maximum energy of membrane phonons, and then decreases the activity due to hindering of conformational transitions in the enzyme molecule.
研究了激素混合物（皮质醇和肾上腺素）在结合过程中对红细胞膜的作用。通过原子力显微镜阐明了膜结构的变化；通过荧光法估计了红细胞悬液中不同激素浓度下脂质双层的微粘度以及Na(+)、K(+)-ATP酶活性的变化。结果表明，皮质醇和肾上腺素竞争结合位点。一种能非特异性结合到膜上的激素会阻碍另一种激素的结合。在这些激素的混合物中，皮质醇在结合位点竞争中获胜；与此同时，膜的微粘度增加了25%，这与单独作用于皮质醇所产生的微粘度变化相对应。竞争关系也影响了Na(+)、K(+)-ATP酶活性，这通过酶活性的第二个最大值的出现得以表明。据推测，红细胞膜微粘度的增加首先由于膜声子最大能量的增加而提高了Na(+)、K(+)-ATP酶活性，然后由于阻碍酶分子中的构象转变而降低了活性。
