Opposite effects of polyamines on glutamate deamination in isolated renal tubules and permeabilized kidney cortex mitochondria of rabbit.
The effect of polyamines on glutamate deamination has been studied in both isolated tubules and permeabilized kidney cortex mitochondria of rabbit. Spermine, spermidine and putrescine resulted in a decrease of ammonium release in isolated renal tubules incubated with glutamate in the presence of MSO and AOA, inhibitors of glutamine synthetase and aminotransferases, respectively. This was not due to the inhibition of glutamate transport across renal tubular membranes since transport of [14C]glutamate into brush border membranes vesicles was not decreased by polyamines. In contrast, polyamines stimulated glutamate deamination in permeabilized mitochondria. This effect was additive to the action of ADP, an allosteric activator of glutamate dehydrogenase. Since these compounds decreased both glutamate-induced mitochondrial swelling as well as [14C]glutamate accumulation in mitochondria, the inhibitory effect of polyamines on glutamate deamination in renal tubules might be due to a diminished glutamate transport across the mitochondrial membrane.
Jarzyna
R
R
Institute of Biochemistry, Warsaw University, Poland.
Zabłocki
K
K
Lietz
T
T
Bryła
J
J
D000818:Animals; D003641:Deamination; D018698:Glutamic Acid / Q000378:metabolism*; D007672:Kidney Cortex / Q000378:metabolism* / Q000648:ultrastructure; D007684:Kidney Tubules / Q000378:metabolism* / Q000648:ultrastructure; D008928:Mitochondria / Q000378:metabolism; D011073:Polyamines / Q000494:pharmacology*; D011817:Rabbits
D011073:Polyamines; D018698:Glutamic Acid