Fructose 2,6-bisphosphate and glucose 1,6-bisphosphate in rabbit erythroid cells during differentiation.

Fructose 2,6-bisphosphate concentration and 6-phosphofructo-2-kinase activity markedly decrease during differentiation of rabbit erythroid cells, being higher in erythroblasts (654 +/- 97 pmol/10(9) cells; 238 +/- 81 U mu/10(9) cells) than in reticulocytes (40 +/- 15 pmol/10(9) cells; 11 +/- 3 U mu/10(9) cells) and much higher than in mature erythrocytes (10 +/- 0.8 pmol/10(9) cells; 2 +/- 1 U mu/10(9) cells). The enzymatic activities involved in glucose 1,6-bisphosphate metabolism also decrease, but the levels of aldohexose 1,6-bisphosphates remain essentially constant during differentiation of erythroid cells.