Intramitochondrial inclusions in the kidney of the pygmy mouse.
Intramitochondrial inclusions averaging 1000 A in diameter were observed in the cells of the proximal convoluted tubules in samples of kidneys from pygmy mice, Baiomys taylori. Electron microscopic study of unstained sections and mitochondrial fractions showed that these inclusions are lipid and found at a S.G. 1.37 in a linear sucrose gradient. Renal glycogen, inorganic phosphate and plasma sodium were significantly higher in the pygmy mouse and plasma calcium was lower, as compared with the laboratory mouse. We believe these intramitochondrial inclusions to be lipid which accumulates divalent cations, particularly calcium, which acts as a sodium pump allowing the pygmy mouse to conserve water and adapt to its environment.
D000818:Animals; D002458:Cell Fractionation / Q000379:methods; D007672:Kidney Cortex / Q000648:ultrastructure*; D007687:Kidney Tubules, Proximal / Q000648:ultrastructure; D008854:Microscopy, Electron; D009115:Muridae / Q000502:physiology*; D013367:Submitochondrial Particles / Q000648:ultrastructure*