Antifungal azoles are widely used in medicine, agriculture, and material protection and several antifungal azoles have been found in environmental samples. Although these compounds were designed to inhibit fungal enzymes such as lanosterol-14-demethylase (cytochrome P450 (CYP) 51), it is well established that the inhibitory actions of azoles are not specific for fungal CYP isozymes.

We refined a gill filament assay to determine the inhibition of CYP1, measured as reduced 7-ethoxyresorufin-O-deethylase (EROD) activity, in rainbow trout (Oncorhynchus mykiss) gill tissue ex vivo. The advantage of this method is that both induction and inhibition of EROD are performed ex vivo. Among thirteen azoles studied, the five that caused the strongest inhibition of gill EROD activity at a concentration of 5 μM were selected for concentration–response assessment. These compounds (bifonazole, clotrimazole, imazalil, miconazole, and prochloraz) showed IC₅₀ values ranging from 0.1 to 1.5 μM. CYP19 (aromatase) inhibition was measured using microsomes from rainbow trout brains. Concentration-response curves for CYP19 inhibition were determined for letrozole, bifonazole, clotrimazole, imazalil, miconazole and prochloraz, which gave IC₅₀ values ranging from 0.02 to 3.3 μM. It was further found that mixtures of the five most potent azoles reduced both CYP1 and 19 catalytic activity in an additive fashion (IC₅₀ = 0.7 μM and 0.6 μM, in the respective assay). Bifonazole (IC₅₀ = 0.1 μM) is not previously known to inhibit CYP1 activity.

The additive inhibition of CYP1 and CYP19 catalytic activity is an important finding of the present study. We conclude that this additive action of azoles could mediate adverse impacts on CYP regulated physiological functions in environmentally exposed fish.

抗真菌唑类广泛用于医学，农业和材料保护中，并且在环境样品中发现了几种抗真菌唑类。尽管设计了这些化合物来抑制真菌酶，例如羊毛甾醇14-脱甲基酶（细胞色素P450（CYP）51），但众所周知，唑类的抑制作用对真菌CYP同工酶不是特异的。

我们精制鳃灯丝测定以确定CYP1的抑制，如7-ethoxyresorufin-减少的测量ø -deethylase（EROD）活性，虹鳟鱼（虹鳟）鳃组织离体。这种方法的优点是离体诱导和抑制EROD都可以进行。在所研究的13种唑中，选择了在浓度为5μM时对EROD活性的抑制作用最强的5种用于浓度响应评估。这些化合物（联苯苄唑，克霉唑，咪唑，咪康唑和丙草胺）的IC ₅₀值范围从0.1到1.5μM。使用虹鳟鱼脑中的微粒体测量CYP19（芳香化酶）的抑制作用。确定了来曲唑，联苯苄唑，克霉唑，咪唑，咪康唑和丙草胺对CYP19抑制的浓度-响应曲线，其IC ₅₀值为0.02至3.3μM。进一步发现，五种最强效唑的混合物以加性方式降低了CYP1和19的催化活性（ 在各自的测定中，IC ₅₀分别为0.7μM和0.6μM ）。联苯唑（IC ₅₀  = 0.1μM）以前不知道抑制CYP1活性。

CYP1和CYP19催化活性的加和抑制是本研究的重要发现。我们得出的结论是，唑类的这种加和作用可能介导对环境暴露的鱼类中CYP调节的生理功能的不利影响。