Inorganic phosphate enhances phosphonucleotide concentrations in cultured fetal rat cortical neurons.
Our laboratory has recently characterized saturable Na(+)-dependent P(i) import into cultured fetal rat cortical neurons and shown that a substantial fraction of the P(i) so accumulated is incorporated into ATP. We now report that the ATP, NADPH and intracellular free P(i) ([P(i)]i) concentrations of cultured fetal rat cortical neurons are dependent on the extracellular P(i) concentration ([P(i)]e). [ATP], [NADPH] and [P(i)]i display a hyperbolic dependence upon [P(i)]e, being significantly increased after incubation with [P(i)]e of > or = 10 microM, and maximal at > or = 500 microM. Increases in both [ATP] and [NADPH] are abolished in the absence of glucose. In the absence of extracellular P(i), both [ATP] and [P(i)]i decline over time. Our data suggest that in cultured fetal rat cortical neurons [P(i)]e has a direct effect on glucose utilization, stimulating both ATP and NADPH synthesis via glycolysis and the pentose phosphate pathway.
Glinn
M
M
Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA.
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Paul
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D000227:Adenine Nucleotides / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000494:pharmacology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism*; D005333:Fetus; D005947:Glucose / Q000494:pharmacology; D006019:Glycolysis; D009249:NADP / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats
D000227:Adenine Nucleotides; D010710:Phosphates; D000249:Adenosine Monophosphate; D009249:NADP; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D005947:Glucose; D002118:Calcium