Clearance of lactate and protons following acute lactacidosis: a comparison between seawater- and freshwater-adapted rainbow trout (Salmo gairdneri).

Acute lactacidosis was induced by intra-arterial infusion of lactic acid in seawater-adapted (SW) rainbow trout to examine the dynamics of the metabolic H+ load (delta Hm+) and La- load (delta La-) in the blood. The results were compared with an analogous study on freshwater-adapted (FW) trout by Turner et al. (1983). Following lactic acid infusion, SW trout experienced a less severe acid-base disturbance, and recovered much more quickly than did FW trout. The rates of disappearance of delta Hm+ and delta La- from blood in SW trout were unequal, resulting in a H+ deficit (delta La- - delta Hm+, signs considered) not seen in the FW animals. Unlike the findings on FW trout by Turner et al. (1983), the present data indicate that differential removal of H+ from blood, through net transfers to the environmental water, probably plays an important role in the development of the H+ deficit in SW trout.