Lactate Production in Isolated Swim Bladder Tissue of the European Eel Anguilla anguilla

Abstract

Lactate formation of isolated swim bladder epithelium (gas gland cells) of the European eel Anguilla anguilla has been analyzed with a modified Ussing chamber over periods of up to 6 h. The rate of lactate production in these preparations was in the range of 120-250 nmol · min⁻¹ · g⁻¹ wet wt, which is typical for inactive swim bladder tissue, that is, during periods of no gas deposition. The swim bladder epithelium proved to be highly polar; about 80% of the lactate was released to the serosal side and only 20% to the luminal side. Under control conditions the rate of lactate release of the swim bladder epithelium decreased by about 25%-30% over the 6-h incubation period. Neither adrenaline nor the c-AMP analog dibutyryl-c-AMP had any influence on the rate of lactate formation of the tissue. The rate of lactate formation was, however, dependent on the extracellular glucose concentration. A long-lasting stimulation of lactate formation was achieved with bovine insulin and with carbachol at a concentration ...