Intracellular ion levels in erythrocytes and hepatocytes isolated from three teleost species

Abstract

Intracellular concentrations of Na+ and K+ were similar (∼75 mmol l−1) in rainbow trout Oncorhynchus mykiss hepatocytes directly following isolation by collagenase digestion, but partial recovery occurred over 6 h with K+ levels increasing to 110 mmol l−1 and Na+ levels decreasing to 42 mmol l−1. Black bullhead Ameiurus melas hepatocytes exhibited higher intracellular concentrations of K+ (90 mmol l−1) than Na+ (55 mmol l−1) with no recovery occurring over 6 h following cell isolation. Concentrations of Na+, K+ and Cl− in eel Anguilla rostrata hepatocytes were similar (∼ 55 mmol l−1) following isolation, with no recovery occurring over time. Erythrocytes from all species apparently did not experience an intracellular ion imbalance following isolation as indicated by high K+ levels (<140 mmol l−1) and low Na+ levels (<40 mmol l−1) during the entire 24‐h monitoring period. Although hepatocytes from all species exhibited an ion imbalance post‐isolation, comparison of their in vitro intracellular Na+ and K+ concentrations with those in plasma demonstrated that directionally correct ion gradients still exist across the cell membrane, albeit differing from those that would be found in the tissue in vivo.