Red blood cell glycolysis and potassium type in sheep

Based on the observations made on human and dog red blood cells, it was recently proposed that the response of red cell glycolysis to variations in the levels of specific cations in an evolutionary adaptation in response to a specific cellular environment. We have now examined the effect of K+ and Na+ on the activity of pyruvate kinase (PK) in the red blood cells from 2 genetically different types of sheep high potassium (HK) and low potassium (LK). The results indicate that K+ stimulate glucose consumption and the activity of PK in both types of sheep. It thus appears that red cell PK from LK sheep does not fit into the concept of cellular environment and PK activity.