The action of stress hormones on the structure and function of erythrocyte membrane.
The action of a mixture of hormones (cortisol and adrenaline) on erythrocyte membrane during their binding was investigated. Changes in the membrane structure were elucidated by atomic force microscopy; microviscosity of the lipid bilayer and changes in the activity of Na(+),K(+)-ATPase at different concentrations of the hormones in erythrocyte suspension were estimated by the fluorescence method. Cortisol and adrenaline were shown to compete for the binding sites. A hormone that managed to bind nonspecifically to the membrane hindered the binding of another hormone. In a mixture of these hormones, cortisol won a competition for the binding sites; therewith, microviscosity of the membranes increased by 25%, which corresponds to a change in microviscosity produced by the action of cortisol alone. The competitive relationships affected also the Na(+),K(+)-ATPase activity, which was indicated by appearance of the second maximum of enzyme activity. It is assumed that an increase in microviscosity of erythrocyte membrane first raises the Na(+),K(+)-ATPase activity due to a growth of the maximum energy of membrane phonons, and then decreases the activity due to hindering of conformational transitions in the enzyme molecule.
FSBI Research Institute of Biochemistry SD RAMS, Novosibirsk, 630117, Russia. pwm64@ngs.ru.
Pavel V
PV
Mokrushnikov
Lev E
LE
Panin
Boris N
BN
Zaitsev
D000818:Animals; D002478:Cells, Cultured; D004338:Drug Combinations; D004837:Epinephrine / Q000008:administration & dosage*; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure*; D006854:Hydrocortisone / Q000008:administration & dosage*; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014783:Viscosity
D004338:Drug Combinations; D000254:Sodium-Potassium-Exchanging ATPase; D006854:Hydrocortisone; D004837:Epinephrine