Target cells for 1,25-dihydroxyvitamin D3were demonstrated in the adrenal medulla by frozen-section autoradiography. The appearance of these target cells was age-dependent in neonatal mice. Immunocytochemical staining for phenylethanolamine-N-methyltransferase revealed that both epinephrine and non-epinephrine cells concentrate 1,25-dihydroxyvitamin D3in their nuclei. In contrast, immunocytochemical staining for “vitamin D-dependent calcium-binding protein” (D-CaBP) demonstrated that D-CaBP immunoreactivity is localized in only a small percentage of adrenomedullary cells, in mice and rats. Comparison of PNMT and D-CaBP immunoreactivities in sequential sections showed that epinephrine-producing cells do not contain D-CaBP. These results indicate that adrenal medullary cells have receptors for 1,25-dihydroxyvitamin D3and that 1,25-dihydroxyvitamin D3may directly affect certain functions of these endocrine ce
展开▼
