Divalent cations and inorganic phosphate metabolism in starved Tetrahymena

1974 ◽  
Vol 338 (2) ◽  
pp. 554-560 ◽  
Author(s):  
Edna S. Kaneshiro ◽  
Sari Scott ◽  
Robert L. Conner
2017 ◽  
Vol 133 ◽  
pp. 74-85 ◽  
Author(s):  
Fernando Santos-Beneit ◽  
María Ordóñez-Robles ◽  
Juan F. Martín

1961 ◽  
Vol 39 (12) ◽  
pp. 1879-1894
Author(s):  
Rhoda Blostein ◽  
David Rubinstein ◽  
Orville F. Denstedt

The rate of passage of cations across the red cell membrane, in the direction of the respective ionic gradients, in blood preserved with glucose at 4 °C, is not diminished upon the addition of inosine, notwithstanding the induced formation of substantial amounts of phosphate esters, including ATP, in the cells. The movement of cations, however, is retarded on the addition of glucose or inorganic phosphate, and on increase in the concentration of hydrogen ions. It would appear, therefore, that the movement of cations across the membrane, at 4 °C, is influenced little, if at all, by the metabolic activity of the cell.When the temperature of the preserved blood is returned to 37° the rate of movement of cations across the cell membrane against their respective gradients is greatest in cells which had either been preserved or have been incubated with inosine even if the remainder of the inosine has been removed. Inosine is more effective than glucose in bringing about the restoration of cation composition in preserved red cells at 37°. The degree of restoration is greater in the presence of glucose than in its absence. Arsenate inhibits the transport of cations against the gradients. Evidence is given that the capacity of the cells to restore the cation distribution at 37 °C is determined largely by the concentration of the phosphate ester intermediates.


1991 ◽  
Vol 124 (6) ◽  
pp. 679-684 ◽  
Author(s):  
Heide S. Cross ◽  
Meinrad Peterlik

Abstract. Embryonic chick jejunum maintained in organ-culture exhibits a characteristic stage-specific pattern of responses to calcitriol and T3. Whereas induction of luminal Na+/inorganic phosphate and Na+/D-glucose transport by calcitriol was only possible at an advanced state of differentiation prior to hatching on day 20, the sterol induced cellular calcium transport with high efficiency even in undifferentiated enterocytes in day 15 embryonic intestine. T3 had no effect at all on calcium transport, but induced Na+/inorganic phosphate transport at all stages of epithelial maturation. In contrast, Na+/D-glucose transport was effectively induced by T3 only in relatively immature intestinal epithelium. T3, at a medium concentration of 10−8 mol/l, in a permissive fashion potentiated the effects of calcitriol (10−10−10−7 mol/l) on calcium transport as well as on Na+/inorganic phosphate and Na+/D-glucose transfer. Thereby, T3 facilitated induction of transport activities by calcitriol against differentiation-related restraints. By facilitating the expression of genomic actions of calcitriol, T3 may thus play an important role in the regulation of calcium and phosphate metabolism.


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