BIOSYNTHESIS OF NOVEL ADRENOCORTICAL STEROIDS

描述（改编自申请人的摘要）：强心苷是 广泛用于医药植物来源的甾体化合物 和基础科学。 它们以高亲和力和特异性结合于 钠钾泵上高度保守的位点。 压倒性的结构 和功能的证据表明，存在的异构体哇巴因在 循环和包括人和牛在内的哺乳动物的组织。 证据量充分 表明肾上腺皮质可能是 循环异构体（即，肾上腺衍生的内源性哇巴因，AEO）。 然而，尚未描述哺乳动物的AEO生物合成。 这次调查的成功结果可能是一个重大进展 在类固醇生物化学中的作用，并进一步证明AEO 和相关的类固醇具有生理和医学意义。 的 提案描述了使用既定程序进行的实验， 培养的牛肾上腺皮质组织和细胞合成AEO。 目的是：1）确定是否常见的类固醇前体 支持AEO和醛固酮的合成和肾上腺分泌; 2）使用 放射性标记的前体，以确定它们是否可以通过 AEO的有序顺序过程，以及途径 与醛固酮不同; 3）确定功能活性 通过分析分泌物质的结合和抑制作用， 对钠泵的作用机制，以及4）研究结构 分泌的AEO和稳定的生物活性前体， 光谱和核磁共振技术。 的详细知识 肾上腺物质的结构可以提供新的见解， 设计改进的强心剂以及新的药物， 受体结合和肾上腺生物合成。

DESCRIPTION (Adapted from applicant's abstract): Cardiac glycosides are steroidal compounds of plant origin that enjoy widespread use in medicine and the basic sciences. They bind with high affinity and specificity to a highly conserved site on the sodium-potassium pump. Overwhelming structural and functional evidence shows the presence of an isomer of ouabain in the circulation, and tissues of mammals including man and cattle. Much evidence suggests that the adrenal cortex may be the primary source of the circulating isomer (i.e., an "adrenal derived endogenous ouabain, AEO). However, the biosynthesis of AEO by mammals has not been described. The successful outcome of this investigation may constitute a major advance in steroid biochemistry and lend further credence to the evidence that AEO and related steroids are of physiological and medical significance. The proposal describes experiments using established procedures that investigate the synthesis of AEO by bovine adrenocortical tissue and cells in culture. The aims are: 1) to determine whether common steroidogenic precursors support synthesis and adrenal secretion of AEO and aldosterone; 2) to use radiolabeled precursors to determine whether they can be transformed by an ordered sequential process to AEO, and the point at which the pathway diverges from that for aldosterone; 3) to determine the functional activity of the secreted materials by analysis of the binding and inhibitory mechanism of action on the sodium pump, and 4) to investigate the structure of the secreted AEO and stable biologically active precursors using mass spectral and nuclear magnetic resonance techniques. Detailed knowledge of the structure of the adrenal materials can provide new insights into the design of improved cardiotonics as well as novel agents that interfere with receptor binding and adrenal biosynthesis.