Plasma lipid levels and heart lipoprotein lipase activity in mice under social stress

The study was conducted in mice in order to elucidate whether psycho-social stimulation produced in an interconnecting box system was able to induce alterations in some circulating lipid fractions and in heart lipoprotein lipase (LPL) activity. Two groups of male mice were studied: A--a group isolated in glass jars from weaning to the age of 12-13 weeks and then transferred to the interconnecting box system with a reduced number of female mice, to 26 weeks of age; B--a second group isolated from weaning to 26 weeks of age, as an extremely opposite situation to group A. Control mice were kept in standard cages from weaning to the end of the experiment. Total cholesterol and triglycerides were determined in blood plasma, and heart LPL activity was determined in small portions of the ventricles. Cholesterol decreased significantly in group A (p less than 0.002) and in group B (p less than 0.05) vs. controls. No alterations were observed either in plasma triglycerides or in LPL activity in either of the two groups.