It was pointed out by many researches that keeping the concentration of Ca2+ in cells could increase the survival rate of hypothermic preserved kidneys and the survival rate of transplants. In this study, changes of the concentration of calcium were detected within catoplasm, mitochondria, endoplasmic reticulum and nucleus in the isolated hypothermic storage cat kidney, Ca2+ be marked with calcium cytochemical probe (K2H2Sb2O7) and detected by X-ray microanalysis of microsections. After 24, 48 and 72 hours preservation, the p/b (peak/back) of calcium within cytoplasm and mitochondria increased significantly. There were no obvious changes within endoplasmic reticulum and nucleus. It demonstrates that the Ca2+ were released from calcium pool (except the endoplasmic reticulum, nucleus, mitochondria etc.) to cytoplasm during preservation; and mitochondria can uptake calcium from cytoplasm to some extent, while the calcium concentration of cytoplasm is higher than normal.
Animals ; Calcium ; metabolism ; Cats ; Cryopreservation ; Female ; In Vitro Techniques ; Kidney Cortex ; cytology ; metabolism ; Male ; Spectrometry, X-Ray Emission ; Time Factors

Phospholipase D (PLD) is an enzyme involved in signal transduction and widely distributed in mammalian cells. The signal transduction pathways and role for phospholipid metabolism during hormonal response in cortical collecting duct remain partly undefined. It has been reported that dexamethasone increases transepithelial transport in M-1 cells that are derived from the mouse cortical collecting duct. We investigated the expression and activity of PLD in M-1 cells. Basal PLD activity of M-1 cells cultured in the presence of dexamethasone (5 microM) was higher than in the absence of dexamethasone. Dexamethasone and ATP activated PLD in M-1 cells but phorbol ester did not stimulate PLD activity. Vasopressin, bradykinin, dibutyryl cyclic AMP, and ionomycin were ineffective in activating PLD of the cells. The PLD2 isotype was detected by immunoprecipitation but PLD1 was not detected in M-1 cells. Addition of GTPgammaS and ADP-ribosylation factor or phosphatidylinositiol 4,5-bisphosphate to digitonin-permeabilized cells did not augment PLD activity. In intact cells PLD activity was increased by sodium oleate but there was no significant change between dexamethasone treated- and untreated cells by oleate. These results suggest that at least two types of PLD are present in M-1 cells and PLD plays a role in the corticosteroid-mediated response of cortical collecting duct cells.
Animal ; Biological Transport/drug effects ; Dexamethasone/pharmacology* ; Dose-Response Relationship, Drug ; Drug Interactions ; Glycerophospholipids/analysis ; Isoenzymes/drug effects ; Kidney Cortex/cytology ; Kidney Tubules, Collecting/drug effects* ; Kidney Tubules, Collecting/cytology ; Mice ; Mice, Transgenic ; Oleic Acid/pharmacology ; Phospholipase D/drug effects*