Physicochemical and functional modifications induced by obesity on human erythrocyte membranes
Background Na+,K+‐ATPase activity was evaluated in relation to membrane composition and molecular organization in erythrocyte membranes from obese patients by the amphyphylic molecule 6‐dodecanoyl‐2‐dimethylamino‐naphthalene (Laurdan). Its possible relationship with fat distribution and hyperinsulin...
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Published in | European journal of clinical investigation Vol. 29; no. 5; pp. 432 - 437 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford BSL
Blackwell Science Ltd
01.05.1999
Blackwell Blackwell Publishing Ltd |
Subjects | |
Online Access | Get full text |
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Summary: | Background
Na+,K+‐ATPase activity was evaluated in relation to membrane composition and molecular organization in erythrocyte membranes from obese patients by the amphyphylic molecule 6‐dodecanoyl‐2‐dimethylamino‐naphthalene (Laurdan). Its possible relationship with fat distribution and hyperinsulinaemia was also investigated.
Design
Subjects were 10 obese men (OM), 12 women with subcutaneous obesity (FSO), 10 women with abdominal obesity (FAO) and 41 healthy lean subjects, 26 women (FC) and 15 men (MC). An oral glucose tolerance test was administered to all subjects to evaluate insulin secretion and glucose tolerance.
Results
Na+,K+‐ATPase activity was increased in all obese patients. Values were higher in FSO and FAO than in FC (with FAO greater than FSO) and in OM than in MC. The erythrocyte membrane cholesterol‐to‐phospholipid ratio was increased in obese patients and was significantly different in FSO patients compared with FC. The erythrocyte membrane protein‐to‐phospholipid ratio was also increased in all obese subjects, reaching statistical significance only in FSO vs. FC. The liquid crystalline phase, as tested by Laurdan generalized polarization (GP), was decreased in obese patients, indicating the presence of greater molecular environmental order; all patients groups showed lower GP values than control subjects, but only FAO reached statistical significance compared with FC. There was no evident correlation between membrane Na+,K+‐ATPase activity and insulin levels, nor did membrane composition and properties show any evident relationship with insulin levels.
Conclusion
Both increased Na+,K+‐ATPase activity and altered fluidity and lipid composition were observed in the erythrocyte membrane of all obese patients. These findings are in line with previous observations by our group and indicate that the changes in Na+,K+‐ATPase activity observed in obese patients could be related to changes in plasma membrane organization and composition. |
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Bibliography: | ArticleID:ECI458 ark:/67375/WNG-2QZX8MQ8-W istex:C14B4F90B28E76F98B7CB27B4F3785C41DB41E1B ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0014-2972 1365-2362 |
DOI: | 10.1046/j.1365-2362.1999.00458.x |