The possibility of active form of vitamins A and D as suppressors on adipocyte development via ligand-dependent transcriptional regulators.

The study aimed to systematically examine the effects of fat soluble vitamins and their analogs on terminal differentiation of adipocytes on the cellular and molecular aspects. It is well known that fat soluble vitamins especially vitamins A and D inhibit the differentiation of adipocytes in cultured cells. Furthermore, it has been revealed that the low level of dietary fat soluble vitamins, especially vitamin A and carotenoid actively stimulate the development of adipose tissue, namely bovine marbling in vivo. We have shown that the expression of retinoic acid receptor (RAR) alpha and gamma, retinoid X receptor (RXR) alpha and beta, and vitamin D receptor (VDR) mRNA were abundant in rat adipose tissue and 3T3-L1 cells. The autoregulated amplification and reduction of RAR, RXR and VDR mRNA by their own ligands, were observed in 3T3-L1 cells. Finally, we proposed the model of vitamins A and D as suppressors on adipocyte development through retinoid/thyroid/vitamin D/fatty acid-activated/peroxisomal proliferator-activated receptor's subfamily.