Putrescine uptake regulation in response to alpha-difluoromethylornithine treatment in Leishmania infantum promastigotes.
The putrescine uptake/efflux regulation and their regulatory role on intracellular polyamine pools have been studied in the parasitic protozoa Leishmania infantum. Putrescine uptake was age-dependent with maximal values in logarithmic phase promastigotes and minimal in stationary phase. Moreover, putrescine uptake was activated in response to depletion of intracellular polyamines by alpha-difluoromethylornithine (DFMO)--a well known irreversible enzyme-activated inhibitor of ornithine decarboxylase. Kinetic studies of putrescine uptake induction showed a notable rise in Vmax without Km changes, suggesting a de novo synthesis of putrescine carriers. Putrescine uptake was able to replenish polyamine content and also to recover the proliferative rate in cells treated during 24 hours with DFMO.
Balaña Fouce
R
R
Dpto. Fisiología, Farmacología y Toxicología, Ftad. Veterinaria, Universidad de León, Spain.
Escribano
M I
MI
Alunda
J M
JM
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D004285:Dogs; D000518:Eflornithine / Q000494:pharmacology*; D007700:Kinetics; D007893:Leishmania donovani / Q000187:drug effects / Q000378:metabolism*; D065108:Ornithine Decarboxylase Inhibitors; D011073:Polyamines / Q000378:metabolism; D011700:Putrescine / Q000378:metabolism*; D015854:Up-Regulation
D003470:Culture Media; D065108:Ornithine Decarboxylase Inhibitors; D011073:Polyamines; D011700:Putrescine; D000518:Eflornithine