The role of pinocytosis in the cellular uptake of an amino acid.

Uptake of L- and D-alanine by the rat visceral yolk sac has been studied in vitro in incubations of short duration. It is concluded that much of the uptake of D-alanine is due to fluid-phase pinocytosis and that the plasma membrane L-alanine porter is more stereospecific than has hitherto been supposed.