Tamura Y, Nishikawa T, Yamada K, Yamamoto M, Kumagai A
Arzneimittelforschung. 1979;29(4):647-9.
The effect of glycyrrhetinic acid (GA) and its derivatives on delta 4-5 alpha- and 5 beta-reduction of cortisol, aldosterone and testosterone was investigated on rat liver preparations. In vitro studies demonstrated that GA and its derivatives inhibited 5 beta-reduction to a much greater extent than 5 alpha-reduction. When GA or glycyrrhizin (GL) were administered, 5 beta-reductase activity was significantly suppressed. On the contrary, 5 alpha-reductase was markedly increased though its meachnism remains to be clarified. In human beings 5 beta-reductase is quantitatively the major enzyme and plays an important role in the regulation of cortisol and aldosterone metabolism. Thus from the studies presented here, it can be presumed that the suppression of 5 beta-reductase activity by GA or GL administration may delay the clearance of corticosteroids and prolong the biological half-life of cortisol resulting in the synergism of these steroids and GA or GL.
在大鼠肝脏制剂上研究了甘草次酸（GA）及其衍生物对皮质醇、醛固酮和睾酮的△4-5α-和5β-还原作用。体外研究表明，GA及其衍生物对5β-还原的抑制作用远大于对5α-还原的抑制作用。给予GA或甘草甜素（GL）时，5β-还原酶活性被显著抑制。相反，5α-还原酶虽显著增加，但其机制仍有待阐明。在人类中，5β-还原酶在数量上是主要酶，在皮质醇和醛固酮代谢调节中起重要作用。因此，从这里给出的研究可以推测，给予GA或GL对5β-还原酶活性的抑制可能会延迟皮质类固醇的清除，并延长皮质醇的生物半衰期，从而导致这些类固醇与GA或GL产生协同作用。
