[Evidence for a Na+/NH4+ exchange in the gill of trout adapted to sea water: adrenergic control].

A Na+/NH4+ exchange similar to that characterizing the fish gill in fresh water was shown to function in the trout adapted to sea water with the help of the head perfusion technique. This exchange stimulated by adrenaline through beta adrenoreceptors and inhibited by amiloride added to the external medium.