Characterization of putrescine- and spermidine-transport systems of a rat pancreatic acinar tumoral cell line (AR4-2J).
Polyamines are polycationic molecules essential for cell growth and differentiation. Recent work has focused on cell polyamine-transport systems as a way to regulate intracellular polyamine levels. In this study, we demonstrate the presence of two different active transporters for putrescine and spermidine in a rat tumoral cell line (AR4-2J). The first has a Km of 3.1 microM and a Vmax of 3.7 pmol/15 min per micrograms of DNA for putrescine and the second a Km of 0.42 microM and a Vmax of 4.7 pmol/15 min per micrograms of DNA for spermidine. Competition studies performed between the polyamines confirm the difference between these two carriers; one has an equal affinity for the three main polyamines, and the other has a lower affinity for putrescine. Amino acids do not share this transport system, which is Na(+)-independent. Choline chloride inhibits selectively and in a dose-responsive manner the uptake of putrescine without affecting that of spermidine. These data demonstrate that AR4-2J cells possess two polyamine transporters; one is specific for aminopropyl groups (spermidine and spermine), and the other is choline-sensitive, but cannot discriminate between aminobutyl (putrescine) and aminopropyl groups.
Nicolet
T G
TG
Institut National de la Santé et de la Recherche Médicale, C.H.U. Rangueil, Toulouse, France.
Scemama
J L
JL
Pradayrol
L
L
Seva
C
C
Vaysse
N
N
D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport; D007424:Intracellular Fluid / Q000378:metabolism; D007700:Kinetics; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D011700:Putrescine / Q000493:pharmacokinetics*; D051381:Rats; D012964:Sodium / Q000494:pharmacology; D013095:Spermidine / Q000493:pharmacokinetics*; D014407:Tumor Cells, Cultured
D000596:Amino Acids; D012964:Sodium; D013095:Spermidine; D011700:Putrescine