“…In the guinea-pig, rat and hamster (Alvarado, 1976;Crane, Forstner & Eichholz, 1965;Lyon & Crane, 1966;van Melle & Robinson, 1981), the principal effect of alterations in the external sodium concentration appeared to be a change in Km ('K-kinetics'), whereas in the rabbit and chicken (Goldner, Schultz & Curran, 1969;Kimmich & Randles, 1975), changes in Vmax (' V-kinetics ') were reported. In contrast, all studies on the kinetics ofsodium-activated amino acid transport agree that the main effect of sodium is to reduce the Km for transport (Alvarado & Mahmood, 1974; Curran, Schultz, Chez & Fuisz, 1967; Sepulveda & Robinson, 1978).…”