Social stress profoundly affects lipid metabolism: over-expression of SR-BI in liver and changes in lipids and lipases in plasma and tissues of stressed mice.
We examined the effect of chronic social stress, similar to that endured by humans, on lipid metabolism of mice. The activity of the lipoprotein lipase (LPL) enzyme increased in adrenals, while in plasma it diminished significantly. Hepatic lipase (HL) was strongly affected in liver and adrenal glands, increasing four-fold and three-fold, respectively. At the same time, scavenger receptor class-B type-I (SR-BI), which are considered the high-density lipoprotein (HDL) receptor in the liver, increased significantly. Although the adrenals do not synthesise HL, the increase in HL may facilitate the uptake of HDL cholesterol for the synthesis of corticoids, which increase significantly following chronic stress. The volume of adrenal glands in control animals was significantly higher than in stressed animals (1.23+/-0.12 mm3 versus 0.29+/-0.06 mm3, p<0.001), corresponding with the weight difference of these organs. Medulla volume was also different in the two groups (0.27+/-0.10 mm3 versus 0.04+/-0.02 mm3, p<0.05). Despite this, corticosterone in plasma was significantly higher in stressed animals. Our results shows, for the first time, the effect of chronic social stress on lipid metabolism in general, and in particular on the SR-BI receptor and HL, which is directly involved in cholesterol reverse transport.
Rodríguez-Sureda
Víctor
V
Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 645, E-08028 Barcelona, Spain.
López-Tejero
M Dolores
MD
Llobera
Miquel
M
Peinado-Onsurbe
Julia
J
D000305:Adrenal Cortex Hormones / Q000378:metabolism; D000311:Adrenal Glands / Q000378:metabolism; D000818:Animals; D001053:Apolipoproteins / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D005786:Gene Expression Regulation; D050356:Lipid Metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D051122:Scavenger Receptors, Class B / Q000378:metabolism*; D013312:Stress, Physiological; D017392:Thiobarbituric Acid Reactive Substances
D000305:Adrenal Cortex Hormones; D001053:Apolipoproteins; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; D017392:Thiobarbituric Acid Reactive Substances; D002784:Cholesterol; D008071:Lipoprotein Lipase