Retinol and retinoic acid dose-response curves were obtained for promotion of the differentiation of F9 murine embryonal carcinoma cells with an enzyme-linked immunoadsorbent assay for laminin, a product of differentiated F9 cells. Retinoic acid produced a half-maximum response at 1.3 nM and a maximum response at about 30 nM; retinol was 1/175th as potent. Maximum differentiation required 48 hr...

Retinoic acids are morphogenic signaling molecules that are derived from vitamin A and involved in a variety of tissue functions. Two groups of their nuclear receptors have been identified: retinoic acid receptors (RARs) and retinoic acid X receptors (RXRs). All-trans retinoic acid is the high affinity ligand for RARs, and 9-cis retinoic acid also binds to RXRs with high affinity. In cells at h...

We have studied the effect of retinoic acid on the expression of the neurotrophin receptors trkA, trkC, and p75 by neuroblasts and neurons at different axial levels along the embryonic mouse paravertebral sympathetic chain. In dissociated cultures of sympathetic neuroblasts, retinoic acid inhibited the developmental increase in trkA mRNA expression and the developmental decrease in trkC mRNA ex...

Retinoic acid regulation of one member of the human class I alcohol dehydrogenase (ADH) gene family was demonstrated, suggesting that the retinol dehydrogenase function of ADH may play a regulatory role in the biosynthetic pathway for retinoic acid. Promoter activity of human ADH3, but not ADH1 or ADH2, was shown to be activated by retinoic acid in transient transfection assays of Hep3B human h...

VITAMIN A (RETINOL) is the dietary precursor of several biologically active retinoids of which all-trans retinoic acid (ATRA) is the most potent known metabolite. Extensive research has characterized ATRA as the physiological ligand for the retinoic acid receptor (RAR) family of nuclear hormone receptors, and numerous reports have documented roles for retinoic acid, the RAR, and their related R...

9-cis-Retinoic acid is a naturally occurring biologically active retinoid capable of binding and transactivating both the retinoic acid receptors and the retinoid X receptors. A study was performed to characterize the pharmacokinetics 9-cis-retinoic acid following i.v. bolus administration in the nonhuman primate. Groups of three animals received i.v. bolus doses of 9-cis-retinoic acid of eithe...

Certain thiol-containing compounds catalyze, in a chemical reaction, the isomerization of 9-cis-retinoic acid to a mixture of all-trans-retinoic acid, 9-cis-retinoic acid, 13-cis-retinoic acid, and 9,13-dicis-retinoic acid. In the presence of such catalysts, all-trans-retinoic acid gives rise to the same mixture. Reactions approaching equilibrium contain more all-trans-retinoic acid than either...

Retinoic acid-the active metabolite of vitamin A-influences biological processes by activating the retinoic acid receptor (RAR). In this issue, Schug et al. (2007) demonstrate that retinoic acid also activates the peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta). Remarkably, retinoic acid signaling through RAR or PPARbeta/delta-which depends on cytoplasmic retinoic acid tr...

Abbreviations : ATRA, all-trans-retinoic acid ; DTC, differentiated thyroid cancer ; FTC, follicular thyroid carcinoma ; NIS, Na/I symporter ; NF-kappaB, nuclear factor kappaB; RA, retinoic acid ; RAR, retinoic acid receptor ; RARE, retinoic acid response element ; RXR, retinoid X receptor ; TG, thyroglobuline ; TPO, thyroid peroxydase ; TSHR, thyroid stimulating hormone receptor ; PAX8, paired...