(1) The features of MgATP-dependent Ca2+ accumulation under stimulation with glucose 6-phosphate were studied in rat kidney microsomes. (2) ca2+ accumulated in the presence of MgATP alone does not exceed approx. 2 nmol/mg protein. (3) Glucose 6-phosphate markedly stimulates ca2+ accumulation, up to steady-state levels approx. 15-fold higher than in its absence. (4) The hydrolysis of glucose 6-phosphate by glucose-6-phosphate is essential for the stimulation, as shown by inhibiting the glucose 6-phosphate hydrolysis with adequate concentration of vanadate. Inorganic phospate is accumulated in microsomal vesicles during glucose 6-phosphate-stimulated ca2+ uptake in equimolar amounts with respects to ca2+. (5) Increasing concentrations of glucose 6-phosphate result in increasing stimulations of ca2+ uptake, until a maximal ca2+-loading capacity of approx. 27 nmol/mg microsomal protein is reached. It is suggested that the enlargement of the kidney microsomal ca2+ pool induced by glucose 6-phosphate (an important metabolite in kidney) might play a role in the regulation of ca2+ homeostatis in kidney tubular cells. © 1990.
Fulceri, R., Romani, A., Pompella, A., Benedetti, A. (1990). Glucose 6-phosphate stimulation of MgATP-dependent Ca2+ uptake by rat kidney microsomes. BIOCHIMICA ET BIOPHYSICA ACTA, 1022(1), 129-133 [10.1016/0005-2736(90)90409-H].
Glucose 6-phosphate stimulation of MgATP-dependent Ca2+ uptake by rat kidney microsomes
Fulceri, R.;Benedetti, A.
1990-01-01
Abstract
(1) The features of MgATP-dependent Ca2+ accumulation under stimulation with glucose 6-phosphate were studied in rat kidney microsomes. (2) ca2+ accumulated in the presence of MgATP alone does not exceed approx. 2 nmol/mg protein. (3) Glucose 6-phosphate markedly stimulates ca2+ accumulation, up to steady-state levels approx. 15-fold higher than in its absence. (4) The hydrolysis of glucose 6-phosphate by glucose-6-phosphate is essential for the stimulation, as shown by inhibiting the glucose 6-phosphate hydrolysis with adequate concentration of vanadate. Inorganic phospate is accumulated in microsomal vesicles during glucose 6-phosphate-stimulated ca2+ uptake in equimolar amounts with respects to ca2+. (5) Increasing concentrations of glucose 6-phosphate result in increasing stimulations of ca2+ uptake, until a maximal ca2+-loading capacity of approx. 27 nmol/mg microsomal protein is reached. It is suggested that the enlargement of the kidney microsomal ca2+ pool induced by glucose 6-phosphate (an important metabolite in kidney) might play a role in the regulation of ca2+ homeostatis in kidney tubular cells. © 1990.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/11365/31067
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