Fig. 1.

The components necessary for retinoic acid signaling are present in the rat pineal gland. mRNA expression of the genes encoding the synthetic enzymes retinol dehydrogenase, Rdh10, and the three retinaldehyde dehydrogenases, Raldh1, Raldh2, and Raldh3; the retinal reductase enzyme Rdh12; the retinol transporter Stra6; the retinoic acid receptors, Rara, Rarb and Rarg; and the catabolic enzymes cytochrome P450 family 26 (Cyp26) a1 and Cyp26b1; determined by PCR and gel electrophoresis (a). Protein for RALDH1, RALDH2, RARα and RARβ is present, determined by western blotting (b)