Different mRNA expression profiling of nuclear retinoid, thyroid, estrogen and PPARgamma receptors, their coregulators and selected genes in rat liver and spleen in response to short-term in vivo administration of 13-cis retinoic acid.

Retinoic acids (RAs) and also their analogs (synthetic retinoids and rexinoids) have been regarded as major therapeutic and/or chemopreventive agents and can regulate a number of diverse processes-such as immune system, hormonal systems. In this work we describe different effects of short-term treatment of Wistar male rats with 13-cis retinoic acid on the regulation of retinoic acid receptors (RARs), retinoid-X receptors (RXRs), thyroid hormone receptors (TRs), ERs, 5'-DI, EGFR and erb-B2/neu genes in liver and/or spleen. Using RT-PCR analysis we have found that administration of 13-cis retinoic acid enhanced expression of RARbeta and PPARgamma mRNA, and decreased expression of RARalpha, RARgamma, RXRbeta and TRbeta mRNA in liver. On the other hand, in spleen this treatment resulted in decreased expression of RARalpha, RARbeta, RARgamma, TRalpha and ERbeta mRNA. Our findings indicate distinct modulation of various signal pathways by short-term administration of 13cRA, which also differ in spleen when compared to liver. We suggest that even a short-term treatment of rats with 13cRA may affect a reasonable number of steps in retinoid signaling pathways, a number of which might be very likely extended by long-term treatment of mammals by 13-cis retinoic acid.