Sodium dependence of intestinal active transport of sugars in snail (Cryptomphalus hortensis Müller)

Active transport of sugars (D-galactose, D-glucose, 3-0-methylglucose and L-arabinose) by sacs of everted intestine of snail (Cryptomphalus hortensis) was strongly inhibited, but not abolished, when all Na from the bathing solutions was substituted by K, Tris, Mg or Ca. Absence of Na produced also a marked inhibition of O2 consumption by the tissue. Omission of other cations (K, Ca, Mg), substituted by Tris, did not affect sugar transport or O2 uptake. Sodium seems to play a specific and important but not indispensable rôle in sugar active transport by snail intestine. Since anaerobiosis did not affect sugar transport, this Na role is independent of its effect on O2 uptake.