Immunocytochemical localization of vitamin D-dependent calcium-binding protein in renal tubules of rabbit, rat, and chick

Immunocytochemical localization of vitamin D-dependent calcium-binding protein in renal tubules of rabbit, rat, and chick. Vitamin D-dependent calcium-binding protein (CaBP) was localized in tissue sections of kidneys from rabbits, rats, and chicks using antiserum specific for chick intestinal CaBP. In rabbit kidney, CaBP was present in all cells of the distal convoluted tubule and most cells of the connecting tubule. Fewer, but still a majority, of the cells of cortical collecting ducts contained CaBP. The intensity of immunochemical staining and the number of stained cells decreased markedly in medullary collecting ducts, and only a few collecting duct cells contained CaBP at the junction of the inner and outer medulla. In the rat kidney, CaBP was present in all distal convoluted tubule cells, but the immunochemical staining was less intense than in the rabbit. The protein also was found in most connecting tubule cells of the rat; however, only a few collecting duct cells in the superficial cortex of the rat contained CaBP. CaBP was essentially absent from mid- to deep-cortical collecting duct cells, while a very few collecting duct cells always contained CaBP at the junction of the inner and outer stripes of the outer medulla. In the chick, CaBP was present in distal convoluted tubule cells as the distal convoluted tubule coursed adjacent to the central vein. CaBP was absent from chick collecting duct cells. In all three species CaBP was not detected in the other portions of the nephron. Localisation immunocytochimique de la protéine-de-liaison-du-calcium vitamine D-dépendante dans les tubes rénaux de lapin, de rat et de poulet. La protéine de liaison du calcium vitamine D dépendante (CaBP) a été localisée dans des coupes de reins de lapin, de rat et de poulet à l'aide d'un antisérum spécifique pour la CaBP intestinale de poulet. Dans le rein de lapin, la CaBP était présente dans toutes les cellules du tube contourné distal, et dans la plupart des cellules du tubule connecteur. Un moins grand nombre, mais toutefois la majorité, des cellules des canaux collecteurs corticaux contenait de la CaBP. L'intensité de la coloration immunochimique et le nombre de cellules colorées diminuait considérablement dans les tubes collecteurs de la médullaire, et à la jonction entre la médullaire interne et externe quelques cellules du tube collecteur seulement contenaient de la CaBP. Dans le rein de rat, la CaBP était présente dans toutes les cellules du tube contourné d