Studies on avian erythrocyte metabolism: IX. Relationship of changing organic phosphate composition to whole blood oxygen affinity during development of the ostrich (Struthio camelus camelus)

摘要

(1)2,3-Diphosphoglycericacid(2,3-DPG)ispresentinerythrocytes(RBC)ofthe37-dayostrichembryoataconcentrationof3.7??mole/mlRBC,representing23.5%ofthecellphosphate.(2)Inositoltetraphosphate(inositol-P4)isabsentinredcellsofthe37-dayembryo,appearsintheRBCabout63daysafterhatch,andthereaftergraduallyaccumulatestoalevelof2.8??mole/mlRBCintheadultbird,representing30a€“35%ofthecellphosphate.(3)Inositolpentaphosphate(inositol-P5)ispresentintheerythrocytesofthe37-dayembryoataconcentrationof0.8??mole/mlRBC,reachesapeaklevelof2.9??mole/mlRBCbyDay63afterhatch,andthereafterdeclinestoalevelof1.1??mole/mlRBCintheadultbird.(4)Thecrossovertimewherethemolarconcentrationsofinositol-P5andinositol-P4areequalintheerythrocyteappearstobeabout150daysafterhatch.(5)Thep50ofwholebloodfromthe37-dayostrichembryo,5-dayostrichchick,andadultostrichwas15.4,31.8,and24.9Torr.Thep50ofwholebloodimmediatelyafterhatchcorrelatesbestwithanabruptriseinATPconcentrationbutafter54daysposthatchcorrelatesbestwiththeappearanceofincreasingconcentrationsofinositol-P4andthedecreaseinconcentrationsofATPandinositol-P5.(6)Theappearanceofinositol-P4inthecellscouldbeanadaptivemechanismforregulatingoxygensupplybyswitchingtoamodulatorwhichmaintainsahigheroxygenaffinitythanwouldapredominanceofinositol-P5.