TDO2 and chronic kidney disease: In contrast, cyclin D1 mRNA level was lowest in the LP 100 group compared to other studied groups (Figure 6D), and a strong inverse relationship existed between this gene’s expression and TDO expression (Figure 6E), whereas there was only a slight, non-significant relationship between cyclin D1 expression and the KYN pathway activation marker in rats with CKD treated with LP533401 (Figure 6F).