We model the pathways of nandrolone in the body, an anabolic steroid widely used as a performance enhancing drug (PED). The model generates the dynamics of nandrolone and its metabolites. PED tests check for the presence of a primary metabolite of nandrolone, 19‐NA in urine. To cheat in these tests, PED users typically use inhibitors that reduce the urinary concentration of 19‐NA. One such inhibitor is finasteride. Finasteride’s main effect in the body is the inhibition of reductase enzymes that turn nandrolone into its metabolite 19‐NA. To capture this effect, we include structures for finasteride and reductase enzymes in the model. The model is tested by fundamental structure validity tests. We also show that the model behavior is consistent with experimental data in the literature. We finally investigate the potential ways by which the drug users may cheat in PED tests and make suggestions for improved testing as counter‐measures. © 2021 System Dynamics Society

中文翻译：

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建模nandrolone掺杂药物的药效学及其对反兴奋剂检测的意义

我们模拟了nandrolone在体内的途径，nandrolone是一种合成代谢类固醇，广泛用作性能增强药物（PED）。该模型产生了nandrolone及其代谢产物的动力学。PED测试检查尿液中是否存在主要的代谢物诺龙（19-NA）。为了在这些测试中作弊，PED用户通常使用能降低19-NA尿液浓度的抑制剂。一种这样的抑制剂是非那雄胺。非那雄胺在体内的主要作用是抑制还原酶使甘露酮转变为其代谢产物19-NA。为了捕获这种效果，我们在模型中包括了非那雄胺和还原酶的结构。通过基本结构有效性测试对模型进行测试。我们还表明，模型行为与文献中的实验数据是一致的。我们最终研究了吸毒者在PED测试中作弊的潜在方式，并提出了改进测试的建议，作为对策。©2021系统动力学学会