Sheppard K E, Funder J W
J Steroid Biochem. 1986 Aug;25(2):285-8. doi: 10.1016/0022-4731(86)90430-9.
Binding of tracer or competing steroids to transcortin can compromise specificity studies on receptors for adrenal steroids. Recently Alexis et al. have used cortisol 17 beta acid at high concentrations to prevent steroid binding to any transcortin possibly contaminating rat brain cytosol preparations. On the basis of limited specificity studies of [3H]dexamethasone and [3H]corticosterone binding under such conditions, it was claimed that binding sites for the two steroids are indistinguishable, and it is thus unnecessary to invoke distinct binding sites for each glucocorticoid. We have extended these competition studies in the presence of cortisol 17 beta acid, and shown that in rat hippocampus Type I, corticosterone-preferring glucocorticoid receptors can be clearly distinguished both from transcortin and from Type II, dexamethasone-binding glucocorticoid receptors.
示踪剂或竞争性类固醇与皮质素结合会影响肾上腺类固醇受体的特异性研究。最近，亚历克西斯等人使用高浓度的皮质醇17β酸来防止类固醇与可能污染大鼠脑细胞质制剂的任何皮质素结合。基于在此类条件下对[3H]地塞米松和[3H]皮质酮结合的有限特异性研究，有人声称这两种类固醇的结合位点无法区分，因此没有必要为每种糖皮质激素引入不同的结合位点。我们在存在皮质醇17β酸的情况下扩展了这些竞争研究，并表明在大鼠海马体中，I型（偏好皮质酮的）糖皮质激素受体可以与皮质素以及II型（结合地塞米松的）糖皮质激素受体明显区分开来。
