Retinoic acid modulates retinoid X receptor α and retinoic acid receptor α levels of cultured brown adipocytes

A novel potential regulatory pathway of brown adipose tissue (BAT) thermogenesis was recently recognized after identifying retinoic acid (RA) as a transcriptional activator of the uncoupling protein (UCP) gene. Here we provide evidence that the UCP responsiveness to RA in primary cultures of brown adipocytes involves RA receptor α (RARα), and show, in the same system and also in CHO cells, that RA down-regulates the steady-state levels of RARα and especially of retinoid X receptor α, suggesting autoregulation of the retinoid pathway and therefore supporting the idea of a physiological role for it in controlling the thermogenic capacity of BAT.