摘 要：甘草酸在體內水解成甘草次酸，因此甘草酸是甘草次酸的前體藥物，而甘草次酸的藥理作用強于甘草酸。甘草次酸的化學結構類似于甾體激素。甘草次酸和甘草酸是甾體激素代謝失活酶抑制劑，可提高內源性和外源性糖皮質激素的活性。甘草次酸和甘草酸又可作為配體，與糖皮質激素受體結合，由于甘草次酸和甘草酸的糖皮質激素受體激動活性遠低于糖皮質激素，因此是糖皮質激素受體的部分激動拮抗劑。臨床上可將甘草酸作為弱糖皮質激素樣藥物應用，不僅增強糖皮質激素的作用，而且拮抗大劑量糖皮質激素的不良反應。

Abstract: Glycyrrhizic acid is hydrolyzed to glycyrrhetic acid in vivo. Pharmacological action of glycyrrhetic acid is higher than that of glycyrrhizic acid, so glycyrrhizic acid is a prodrug of glycyrrhetic acid. Chemical structure of glycyrrhetic acid is similar to steroid hormone. Glycyrrhetic acid and glycyrrhizic acid are the inhibitors of enzymes in steroid hormone metabolism, therefore they can enhance effects of endogenic and exogenic glucocorticoids. Glycyrrhetic acid and glycyrrhizic acid, as ligands, can combine with glucocorticoid receptor, but receptor activation is far inferior to glucocorticoid. For this reason, glycyrrhetic acid and glycyrrhizic acid are partial agonists of glucocorticoid receptor. In clinic, glycyrrhizic acid may be used as weak glucocorticoid-like drug, not only enhances glucocorticoid effects but also antagonizes adverse reactions of large dose glucocorticoids.