The effect of insulin on glucose transport in rabbit erythrocytes and reticulocytes.
Insulin binding and 3-0-Methylglucose transport have been studied in erythrocyte- and reticulocyte-enriched fractions of blood cells in order to determine if the increased number of insulin binding sites in reticulocytes is associated with a glucose transport response to insulin. In these experiments rabbit reticulocytes demonstrate an eightfold increase in total insulin receptors when compared to erythrocytes. Glucose transport activity in the erythrocyte has Km of 3.2 mM. Reticulocytes demonstrate a saturable glucose transport activity of lower affinity, Km 18.9 mM. Neither the erythrocyte, nor the the reticulocyte glucose transport activity, was capable of an increased response to insulin. the low affinity glucose transport activity in reticulocytes could allow a fourfold increase in facilitated glucose transport at supraphysiological glucose concentrations that might occur in poorly controlled diabetes mellitus.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001786:Blood Glucose / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism*
D001786:Blood Glucose; D007328:Insulin