[The effect of antibiotics (gentamicin) on placental amino acid transport activity (using human placental microvillous membrane vesicles)].

In order to elucidate the effect of antibiotics (gentamicin) on placental amino acids transport, we investigated L-alanine transport using microvillous membrane vesicles prepared from full-term human placental by a rapid filtration technique. 1. The active transport of L-alanine into microvillous membrane vesicles was dependent on Na+ electrochemical gradient (extravesicular greater than intravesicular). And the double reciprocal plot of this Na+ dependent initial uptake rate versus L-alanine concentration exhibited an apparent Km of 0.79 + 0.23mM and a Vmax of 3.56 + 0.70n mol/mg protein/20 sec. 2. Gentamicin did not affect the Km value of this Na+ dependent L-alanine transport kinetics (0.77 + 0.19 mM [lmM gentamicin], 0.79 + 0.21mM [10mM gentamicin]). On the other hand, gentamicin apparently decreased, the Vmax value of this transport kinetics (1.99 + 0.48n mol/mg protein/20 sec [1mM gentamicin], 1.12 + 0.32n mol/mg protein/20 sec [10mM gentamicin]).