Beach D H, Goad L J, Holz G G
Department of Microbiology and Immunology, S.U.N.Y. Health Science Center 13210.
Mol Biochem Parasitol. 1988 Nov;31(2):149-62. doi: 10.1016/0166-6851(88)90166-1.
Promastigotes of 36 World Health Organization reference (and other) strains of 6 species and 10 subspecies of Leishmania were cultured in the presence of 3 antimycotic azole drugs (ketoconazole, itraconazole, fluconazole) and their population growth determined. A representative of each subspecies was also analyzed for its sterol composition. For all strains the order of azole drug activity with respect to both growth and sterol biosynthesis inhibition was itraconazole greater than or equal to ketoconazole greater than fluconazole. The inhibitory actions of the three azole drugs were greater on L. donovani and L. braziliensis subspecies and on L. mexicana amazonensis than on L. aethiopica, L. major, L. tropica and L. mexicana mexicana. The nature of the changes in sterol composition caused by the drugs was the same for all strains. The normal, major endogenous sterols of the promastigotes (5-dehydroepisterol and ergosterol) were reduced in amount to 1-2% of the total free sterols and were replaced by endogenous 14 alpha-methyl sterols and exogenous cholesterol. The changes occurred rapidly, were drug concentration dependent and coincided with growth inhibition. Six strains of those Leishmania species less sensitive to the azole drugs could be subcultured indefinitely at reduced growth rates in the presence of a ketoconazole concentration causing the same extraordinary alterations in sterol composition. This suggested that the bulk membrane functions of sterols in leishmanias can be served by 14 alpha-methyl sterols and cholesterol, albeit imperfectly, while traces of 14 alpha-desmethyl sterols are needed for uncharacterized metabolic functions.
36株世界卫生组织参考菌株（以及其他菌株），分属于利什曼原虫属6个种和10个亚种，其前鞭毛体在3种抗真菌唑类药物（酮康唑、伊曲康唑、氟康唑）存在的情况下进行培养，并测定其群体生长情况。每个亚种的一个代表菌株也被分析了其甾醇组成。对于所有菌株，就生长抑制和甾醇生物合成抑制而言，唑类药物的活性顺序为伊曲康唑≥酮康唑＞氟康唑。这三种唑类药物对杜氏利什曼原虫和巴西利什曼原虫亚种以及亚马逊利什曼原虫的抑制作用比对埃塞俄比亚利什曼原虫、硕大利什曼原虫、热带利什曼原虫和墨西哥利什曼原虫更强。药物引起的甾醇组成变化的性质在所有菌株中都是相同的。前鞭毛体正常的主要内源性甾醇（5-脱氢表甾醇和麦角甾醇）的含量减少至总游离甾醇的1%-2%，并被内源性14α-甲基甾醇和外源性胆固醇所取代。这些变化迅速发生，与药物浓度有关，并且与生长抑制同时出现。在存在导致甾醇组成发生相同异常变化的酮康唑浓度的情况下，6株对唑类药物不太敏感的利什曼原虫物种菌株可以以降低的生长速率无限传代培养。这表明利什曼原虫中甾醇的大部分膜功能可以由14α-甲基甾醇和胆固醇来承担，尽管并不完美，而痕量的14α-去甲基甾醇对于未明确的代谢功能是必需的。
