Epoxidation is the preferred pathway of first-stage metabolism of abiraterone acetate in brown bullhead (Ameiurus nebulosus).

Twenty juvenile individuals of brown bullhead (Ameiurus nebulosus), average weight 77 g, were fed by abiraterone acetate prodrug dissolved in olive oil via gastric probe. Dose applied was 3 mg/10 g fish weight. After feeding, they were let out into aquarium and kept there for 3 days. Aquarium water containing excreted metabolites was extracted, and sample was purified and finally analyzed by means of HPLC/MS. Expected both primary (products of hydroxylation) and secondary (products of glucuronidation and sulfatation) metabolites of abiraterone acetate were identified. The NMR measurement of one of the prevailing metabolites presumed to be one of possible hydroxy-abiraterones discovered that it is not hydroxy-abiraterone but abiraterone 16,17-epoxide. Closer analysis of MS2 and MS3 spectra revealed that one of presumed hydroxy-abiraterone acetates and also some secondary metabolites are probably 16,17-epoxides.

Metabolism of obeticholic acid in brown bullhead (Ameiurus nebulosus).

Analysis of brown bullhead (Ameiurus nebulosus) bile by ultra performance liquid chromatography high-resolution mass spectrometry (UPLC/HRMS) revealed a series of bile acids similar to those found in humans. Accordingly, we chose this fish as a model organism to examine the metabolism of obeticholic acid, a bile acid used to treat a number of human liver diseases and the one that has the potential to occur as an environmental contaminant. The taurine and glycine conjugates of obeticholic acid and keto-obeticholic acid were identified, as well as the D-cysteinolic acid conjugate of obeticholic acid, likely a metabolite specific to fish. In addition, metabolites of obeticholic acid (sulphate and glucuronide) and several hydroxy-obeticholic acid derivatives were found, representing typical pathways of primary and secondary steroid metabolism. Brown bullhead exposed to obeticholic acid at a dose of 100 mg/kg gave no overt signs of distress or toxicity.

Integrated assessment of PAH contamination in the Czech Rivers using a combination of chemical and biological monitoring.

This study investigated polycyclic aromatic hydrocarbons (PAH) pollution of selected rivers in the Czech Republic. Integrated evaluation was carried out using combination of chemical and biological monitoring, in which we measured content of 1-hydroxypyrene (1-OHP) in chub bile and priority PAH in water samples obtained by exposing the semipermeable membrane devices at each location. The concentrations of 1-OHP in bile samples and sum of priority PAH in water sampler ranged from 6.8 ng mg protein(-1) to 106.6 ng mg protein(-1) and from 5.2 ng L(-1) to 173.9 ng L(-1), respectively. The highest levels of biliary metabolite and PAH in water were measured at the Odra River (the Bohumín site), which is located in relatively heavily industrialized and polluted region. Statistically significant positive correlation between biliary 1-OHP and sum of PAH in water was also obtained (P < 0.01, r s = 0.806).