Walters M R, Wicker D C, Riggle P C
J Mol Cell Cardiol. 1986 Jan;18(1):67-72. doi: 10.1016/s0022-2828(86)80983-x.
Specific receptors for 1,25-dihydroxyvitamin D3, the active hormonal form of vitamin D3, were demonstrated in low salt chromatin preparations from normal rat hearts. Sucrose gradient analysis of KCl-extracted chromatin yielded a significant (P less than 0.005) peak of specific [3H]1,25-dihydroxyvitamin D3 binding in the 3.6S region. The peak of [3H]1,25-dihydroxyvitamin D3 binding was abolished by excess 1,25-dihydroxyvitamin D3, but not by 50 nM 25-hydroxyvitamin D3 nor by 1.0 microM levels of estradiol-17B, cortisol, or promegestone, demonstrating steroid specificity characteristic for such receptors. Upon Scatchard analysis this putative cardiac 1,25-dihydroxyvitamin D3 receptor yielded a single binding component with high affinity (KD = 0.36 nM) and low capacity (Nmax = 33 fmol/g tissue). Coupled with evidence for the presence of calcium binding proteins in this tissue, these observations suggest functional roles for 1,25-dihydroxyvitamin D3 and its receptors in cardiac muscle, possibly in regulating intracellular effects of calcium.
在从正常大鼠心脏制备的低盐染色质中，证实了维生素D3的活性激素形式1,25 - 二羟基维生素D3的特异性受体。对氯化钾提取的染色质进行蔗糖梯度分析，在3.6S区域产生了一个显著的（P小于0.005）特异性[3H]1,25 - 二羟基维生素D3结合峰。过量的1,25 - 二羟基维生素D3可消除[3H]1,25 - 二羟基维生素D3结合峰，但50 nM的25 - 羟基维生素D3、1.0 microM水平的雌二醇 - 17β、皮质醇或普美孕酮则不能消除，这表明了此类受体具有类固醇特异性特征。经Scatchard分析，这种推测的心脏1,25 - 二羟基维生素D3受体产生了一个具有高亲和力（KD = 0.36 nM）和低容量（Nmax = 33 fmol/g组织）的单一结合成分。结合该组织中存在钙结合蛋白的证据，这些观察结果表明1,25 - 二羟基维生素D3及其受体在心肌中具有功能作用，可能参与调节钙的细胞内效应。
