Steady-state volumes and metabolism-independent osmotic adaptation in mammalian erythrocytes.
Erythrocytes of various mammalian species -- including human -- maintain osmotic balance with the blood plasma (osmotic activity 270-310 mosmol). However, their intracellular levels of osmotically active ions (potassium, sodium, chloride, and hydrogencarbonate), water content and osmotic resistance deviate significantly. In the present report we study the relationship among intracellular water, potassium and sodium levels of the erythrocytes of various mammalian species and in the developing calf. In addition, the osmotic resistance, K(+) (Rb(+)) uptake and the DPH fluorescence anisotropy of various erythrocytes and erythrocyte ghost membranes were correlated. The results show no statistically significant relationship between erythrocyte water content and [K(+)+Na(+)] levels or K(+)/Na(+) ratios. The reversal of erythrocyte K(+)/Na(+) ratios coincides with the decrease of steady-state ATP levels in the developing calf. The mobility of lipids within the hydrophobic inner layer of the plasma membrane relates closely to passive K(+) (Rb(+)) uptake, and plays a significant role in regulatory volume changes.
Bogner
Peter
P
Department of Clinical Chemistry, University of Pécs, Faculty of Medicine, Hungary.
Sipos
Katalin
K
Ludány
Andrea
A
Somogyi
Béla
B
Miseta
Attila
A
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D016880:Anisotropy; D055592:Biophysical Phenomena; D001703:Biophysics; D015153:Blotting, Western; D002412:Cations; D002462:Cell Membrane / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism / Q000502:physiology*; D006454:Hemoglobins / Q000737:chemistry; D006801:Humans; D007477:Ions; D008353:Mannitol / Q000494:pharmacology; D009995:Osmosis; D011188:Potassium / Q000737:chemistry / Q000494:pharmacology; D012413:Rubidium / Q000737:chemistry; D012964:Sodium / Q000737:chemistry / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D014867:Water / Q000737:chemistry
D002412:Cations; D006454:Hemoglobins; D007477:Ions; D014867:Water; D008353:Mannitol; D000255:Adenosine Triphosphate; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D011188:Potassium