VITAMIN-D-RECEPTOR EXPRESSION IN CHICKEN MUSCLE-TISSUE AND CULTURED MYOBLASTS

Muscle has long been recognized as a target tissue for 1,25-dihydroxy- vitamin D-3 (1,25[OH](2)D-3). Evidence of the presence of VDR is provi ded here, thus supporting the existence of a receptor-mediated mechani sm of action of 1,25(OH)(2)D-3. Vitamin D receptor (VDR) expression is evidenced by detection of VDR-mRNA, through reverse transcription and polymerase chain reaction (RT/PCR), in chicken muscle and muscle cell s (myoblasts) as well as in a variety of tissues such as intestine, ki dney, heart and brain. VDR presence is also demonstrated by Southern b lot of PCR products with a specific VDR-cDNA probe and by immunocytoch emistry carried out on myoblasts and cardiac myocytes. Localization of VDR is mainly nuclear and more faintly detected in the cytosol.