Fig. 1.

Minocycline inhibits RA-degradation in human monocytes. a Representative chromatographs of retinoic acid (RA)-measurements in cell culture supernatants from THP1-cells, each chromatograph representing only a single experiment. Degradation of RA is substantially inhibited in the presence of minocycline (MINO). All-trans-RA elutes with a retention time of ~ 9 min. b Quantitative analysis revealing an inhibition of RA-degradation in monocyte cells. While pretreatment with 10 µM minocycline reveals nearly no effect on RA levels, treatment with 100 µM minocycline results in a striking inhibition of RA-degradation. Results are presented as mean ± SEM, assessed in 4 independent experiments