Detection and developmental changes of the 1,25-(OH)₂-D₃ receptor concentration in mouse skin and intestine

We investigated [³H]1,25-dihydroxyvitamin D₃-specific binding activity in fetal, neonatal, and adult mouse skin to determine (a) during which stage in development the skin develops the capacity to respond to this hormone and (b) whether the hormone binding activity changed during development and maturation. A macromolecule with properties similar to those of the chick intestinal 1,25-dihydroxyvitamin D₃ receptor was detected in the skin and intestine of mouse pups at 17 days of fetal life. 1,25-Dihydroxyvitamin D₃-specific binding activity from both tissues sedimented on linear sucrose gradients at 3.5-3.7S and eluted from DNA cellulose at 0.22 M KCl. At earlier stages of fetal life (12-14 days) receptor-like activity was detected in cytosols prepared from whole-mouse fetuses. 1,25-Dihydroxyvitamin D₃-specific binding activity was quantitated in the skin and intestine throughout development using a chromatin binding assay. Scatchard analysis of saturation binding data showed that the concentration of binding activity in skin increased rapidly after birth and reached a maximum when the mice were 10-19 days old. By contrast, the binding activity that was detected in the fetal and neonatal whole intestine remained low until the mice were weaned. The affinity (K(d)) of the binding activity was similar in skin and intestine at all ages studied. It is concluded that 1,25-dihydroxyvitamin D₃-specific binding activity appears in both skin and intestine of the mouse prior to birth and increases in these two tissues during different stages in development.