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.

Cholesteryl ester

Primary metabolite

10.1016/0014-5793(92)81433-m

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Citations (3)

Contribution of Chevreul to lipid chemistry

OCL (2023)

Claude Leray

Michel Eugène Chevreul entered at 17 the laboratory of Vauquelin, at the Museum. He began his investigations on animal fats in 1811. They appear as yet the most complete and the best executed experiments found in all chemistry. For the first time, he combined fractional solution, crystallization, distillation, melting point determination, and ultimate analysis. All started with the isolation of an acid and solid substance, “margaric acid”, the first of a long list of fatty acids isolated from various fats. Studying saponification, he determined that “anhydrous glycerine” was combining with water. After studying human gallstones, he discovered “cholesterine” (cholesterol). From whale spermaceti, he described “cetin” (mainly cetyl palmitate), containing no glycerol. He isolated from sheep fat a new acid he named “stearic acid”. This component was proposed in a joint patent by Chevreul and Gay-Lussac (1825) for the fabrication of very efficient candles. He discovered several volatile fatty acids in cow and goat butter (from C4 to C10). His master work ( Recherches chimiques sur les corps gras d’origine animale, 1823b ) contains his experimental procedures and his theoretical conclusions on the nature of fats, it may be considered as the first treatise on lipochemistry.

Saponification

Stearic acid

Anhydrous

Animal fat

10.1051/ocl/2023006

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Citations (0)

The P2Y₁ receptor is an ADP receptor antagonized by ATP and expressed in platelets and megakaryoblastic cells

FEBS Letters (1997)

Catherine Léon Béatrice Hechler Catherine Vial Claude Leray Jean‐Pierre Cazenave

P2Y receptor

10.1016/s0014-5793(97)00022-7