TY - JOUR
T1 - Influence of cholesterol on sphingomyelin metabolism and hemileaflet fluidity of rat liver plasma membranes
AU - Nikolova-Karakashian, M. N.
AU - Petkova, H.
AU - Koumanov, K. S.
PY - 1992/2
Y1 - 1992/2
N2 - The objective of this study was to examine the effect of dietary Chol supplementation on SM metabolism in rat liver plasma membranes, as well as on membrane leaflet fluidity characteristics. The membrane Chol content increased significantly during the first 20 days of dietary feeding, but returned to the level of the control group when the diet was continued for another ten days. The initially more fluid outer leaflet of the membrane rigidified as a result of the diet, obliterating the natural asymmetry in the fluidity of the membrane bilayer. Changes in the neutral SMase activity were also observed. These changes were in strong negative correlation (r=-0.978) with the Chol/Pr ratio and are consistent with the in vitro inhibition of SMase activity reported earlier. In contrast, the SM synthesizing enzymes, PC:Cer-PCh and PE:Cer-PEt transferase, were stimulated in course of the dietary Chol feeding. The activity of PC:Cer-PCh transferase was more strongly affected. Our results support the concept that SM metabolism is regulated coordinately with that of Chol. The present work could contribute to the better understanding of the parallel acumulation of SM and Chol observed in a variety of pathological conditions such as atherosclerosis and Niemann-Pick disease.
AB - The objective of this study was to examine the effect of dietary Chol supplementation on SM metabolism in rat liver plasma membranes, as well as on membrane leaflet fluidity characteristics. The membrane Chol content increased significantly during the first 20 days of dietary feeding, but returned to the level of the control group when the diet was continued for another ten days. The initially more fluid outer leaflet of the membrane rigidified as a result of the diet, obliterating the natural asymmetry in the fluidity of the membrane bilayer. Changes in the neutral SMase activity were also observed. These changes were in strong negative correlation (r=-0.978) with the Chol/Pr ratio and are consistent with the in vitro inhibition of SMase activity reported earlier. In contrast, the SM synthesizing enzymes, PC:Cer-PCh and PE:Cer-PEt transferase, were stimulated in course of the dietary Chol feeding. The activity of PC:Cer-PCh transferase was more strongly affected. Our results support the concept that SM metabolism is regulated coordinately with that of Chol. The present work could contribute to the better understanding of the parallel acumulation of SM and Chol observed in a variety of pathological conditions such as atherosclerosis and Niemann-Pick disease.
KW - cholesterol
KW - fluidity
KW - plasma membranes
KW - sphingomyelin metabolism
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U2 - 10.1016/0300-9084(92)90040-L
DO - 10.1016/0300-9084(92)90040-L
M3 - Article
C2 - 1581391
AN - SCOPUS:0026538161
SN - 0300-9084
VL - 74
SP - 153
EP - 159
JO - Biochimie
JF - Biochimie
IS - 2
ER -