Fig 1.
Substrate depletion kinetics of propranolol by trout liver spheroid cultures prepared from two separate fish livers.
Closed circles denote cultures from fish one; open circles denote cultures from fish two (n = 6 at each time point). Values at each time point are mean ± SE. Substrate depletion kinetics determined using two-parameter, exponential decay curve-fit analysis (non-linear regression; Sigma Plot v12.5, Systat Software, San Jose, USA).
Table 1.
Pharmaceuticals used in substrate depletion experiments using trout liver spheroids.
Substrate decrease over total incubation period (%), depletion rates constant (k; h-1) and half-life (t1/2) values are shown as mean ± SD. NSD = no substrate depletion.
Table 2.
Prediction of pharmaceutical metabolism in trout liver spheroids based on ‘read-across’ from human metabolism data.
† Pharmaceuticals are ranked according to the Biopharmaceutics Drug Disposition Classification System (BDDCS) [23] where 1 = High solubility / extensive metabolism; 2 = Low solubility / extensive metabolism; 3 = High solubility / poor metabolism. + Major CYP enzymes believed responsible for the metabolim of pharmaceuticals in humans (modified from [2] with additional data sourced from [44–47].
Table 3.
Comparison of intrinsic hepatic clearance rates (CLINT, HEPATIC) of propranolol and diclofenac by trout liver spheroids with trout, human S9 and human hepatocytes.
Clearance rates for human S9 and hepatocytes are shown as mean ± SD and taken from studies reviewed previously [2]. Clearance rates for trout S9 are taken from two previous fish in vitro studies [2,20]. Where no SD is provided, the data are collated from multiple studies and the figures provided for an indication of comparable rates.
Table 4.
Propranolol depletion over time (%) measured over 24h incubation, calculated depletion rate constants (k; h-1) and half-life (hours) (t1/2) for liver spheroid cultures from individual fish experiments.
Values for each individual fish experiment are mean ± sd from combined spheroid cultures (n = 6 wells). Initial measured dose at time zero was 98 ± 4 μg/L (n = 72 wells). Individual differences between fish were analysed by the natural log transform of the % depletion (normally distributed) and a one-way anova with Tukey post hoc to identify individual fish (fish sharing the same letter A through D are not different to one another). Fish number 12 had significantly slower clearance than any other fish (p<0.001), but has not been excluded from the dataset.