| Autor: |
Behr, Patrick, Kupferberg, Alexandre, Leray, Claude, Schellenbaum, Laurence, Urban, Paul-Francis, Vincendon, Guy, Mersel, Marcel |
| Zdroj: |
FEBS Letters; January 1992, Vol. 313 Issue: 2 p151-154, 4p |
| Abstrakt: |
Incubation of spontaneous transformed cells derived from astrocyte primary cultures with 30 μM 7β-hydroxycholesterol (7β-OH-CH) which is lethal to the cells or with 150 μM isoproterenol reduces the intracellular level of cAMP (4- and 2-fold respectively). Treatment of the cultures with 0.5 mM dibutyryl (db)-cAMP and 7β-OH-CH increases 3-fold the intracellular level of cAMP and both, db-cAMP and isoproterenol, raise the lethal effect of 7β-OH-CH and its esterification on C-3-OH by naturally occurring fatty acids (metabolite). Kinetics studies of net steryl-3-esters hydrolysis revealed that db-cAMP and isoproterenol lower that of cholesteryl-3-esters (2-fold) whereas the opposite is found for the metabolite. These data demonstrate that (i) high cAMP intracellular levels modulate differently the net hydrolysis of cholesteryl-3-esters and metabolite, (ii) isoproterenol acts otherwise than cAMP on 7β-OH-CH esterification, (iii) the cytotoxicity of 7β-OH-CH is linked to its own esterification. The accumulation of metabolite subsequent to db-cAMP or isoproterenol treatment as a result of acyl-CoA:cholesterol acyl transferase activation is discussed. |
| Databáze: |
Supplemental Index |
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