Target Cells for 1,25-Dihydroxyvitamin D 3 in Intestinal Tract, Stomach, Kidney, Skin, Pituitary, and Parathyroid

After mature rats that had been fed on a vitamin D 3 -deficient diet were injected with tritium-labeled 1,25-dihydroxyvitamin D 3 , radioactivity became concentrated in nuclei of luminal and cryptal epithelium of the duodenum, jejunum, ileum, and colon; in nuclei of the epithelium of kidney distal tubules including the macula densa, and in podocytes of glomeruli; in nuclei of the epidermis including outer hairshafts and sebaceous glands; and in nuclei of certain cells of the stomach, anterior and posterior pituitary, and parathyroid. These results reveal cell types that contain receptors for 1,25-dihydroxyvitamin D 3 or metabolites of this compound both in known or hypothesized target tissues and in tissues that were previously unknown to participate in vitamin D 3 metabolism.