Intracisternal microtubules in proximal tubule cells of duck kidney: A serendipitous finding

Abstract

Cytpplasmic microtubules, ubiquitous cell organelles, lie free in the cytosol without being compartmented off by membranes. In rare instances, however, intracisternal microtubules (ICM) have been reported in ganglionic neurons of aging dogs and in the proximal tubule cells (PTC) of rabbit kidneys. We report here the presence of ICM in the PTC of the kidneys of Peking ducks (Anas platyrhynhos).A total of 106 Peking ducks (24 males and 24 females of 9 months, 48 females of 15 months, 6 males of 30 months and 2 males and 2 females of 48 months of age) were anesthetized and exsanguinated. Pieces of kidney cortex were fixed in 4% glutaraldehyde in 0.5M phosphate buffer (pH 7.3) at 29°C for four hours. Samples were post fixed in 2% osmium tetroxide for two hours. One micron sections of Epon-embedded cortices were stained with toluidine blue and thin sections (70-70 nm) contrasted with uranyl acetate and lead citrate were examined with a JEOL 100-S electron microscope at 80 kV.