Structures of the natural and synthetic retinoids used. Structures of atRA, 9-cis-RA,4-[5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-anthracenyl]-benzoic acid (CD367), (E)-2-[2-(5,6,7,8-tetrahydro-3,5,5,8,8-pentamethyl-2-naphthyl)propen-1-yl]-4-thiophenecarboxylic acid (CD2425 or AGN191701), [4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl) carboxamido]benzoic acid (Am580), 6-(3-tert-butyl-4-methoxyphenyl)-2-naphthoic acid (CD417), and 6-[3-adamantyl-4-hydroxyphenyl]-2-naphtalene carboxylic acid (CD437). The selectivity of each compound is indicated according to previously published dissociation constant and EC₅₀data.31,32 43 CD2425 does not transactivate RARs, but transactivates RXRs (EC₅₀ = 54 nmol/L). It binds to RARs with a very weak affinity (kd = 10,000, 1470, and 712 nmol/L for RARα, RARβ, and RARγ, respectively; U. Reichert, personal communication, March 1997). No RXR binding data have been published for this compound.