Fig. 1.

Retinaldehyde reductase activity of AKR1B10 and effect of tolrestat in vitro and in vivo. (A) Retinoid metabolism in COS-1 cells transiently expressing AKR1B10. Cellular retinoid content was measured by HPLC after incubating cells for 30 min with 10 μM retinaldehyde or 10 μM retinol. (B) Determination of tolrestat IC₅₀ for retinaldehyde reductase activity of AKR1B10 using 0.5 μM retinaldehyde as a substrate. (C) Tolrestat inhibition of cellular AKR1B10 activity. COS-1 cells transfected with pCMV-HA-AKR1B10 were incubated with 10 μM all-trans-retinaldehyde and different concentrations of tolrestat. Data are expressed as the percentage of conversion of the retinoid taken up by cells (reduced retinaldehyde or oxidized retinol). Conversion for COS-1 cells transfected with empty vector (pCMV-HA) is shown as a control. Results are expressed as the mean ± SEM of at least three determinations.