Krupka R M, Devés R
Biochim Biophys Acta. 1980 May 8;598(1):134-44. doi: 10.1016/0005-2736(80)90271-0.
Steroids inhibit glucose transport in erythrocytes by binding to sites in the carrier which are exposed on both the outer and inner surfaces of the cell membrane. Some steroids are bound almost exclusively at inner sites (androstendione and androstandione), while others are bound about as firmly on one side as the other (corticosterone). Still others exhibit a moderate preference for the internal site (deoxycorticosterone). The inhibition is in all cases competitive with respect to a substrate which is bound at the same surface of the membrane as the inhibitor. However, in experiments on substrate entry, internally bound inhibitors act in an apparently non-competitive fashion, as expected if the carrier model is valid. This behaviour explains the appearance of competitive, non-competitive and mixed inhibitions with different steroids (Lacko, L., Wittke, B. and Geck, P. (1975) J. Cell Physiol. 86, 673--680).
类固醇通过与载体上暴露于细胞膜内外表面的位点结合来抑制红细胞中的葡萄糖转运。一些类固醇几乎只在内侧位点结合（雄烯二酮和雄烷二酮），而其他类固醇在两侧的结合强度大致相同（皮质酮）。还有一些则对内部位点表现出适度的偏好（脱氧皮质酮）。在所有情况下，这种抑制作用相对于与抑制剂在膜的同一表面结合的底物而言都是竞争性的。然而，在底物进入的实验中，内部结合的抑制剂表现出明显的非竞争性作用方式，这与载体模型有效的预期相符。这种行为解释了不同类固醇出现竞争性、非竞争性和混合抑制的现象（拉科，L.，维特克，B.和格克，P.（1975年）《细胞生理学杂志》86卷，673 - 680页）。
