Surgical removal of perirenal and epididymal adipose tissue decreases serum leptin concentration and increases lipogenic enzyme activities in remnant adipose tissue of old rats.

摘要

BACKGROUND: The rate of lipogenesis and gene expression of lipogenic enzymes in white adipose tissue (WAT) of rats decreases with age. Previously, we showed the inverse relationship between serum leptin concentration and lipogenic enzymes activities in WAT of ageing rats. Based on those results, we postulated that leptin could play some role in the downregulation of lipogenic enzyme genes expression in WAT of old rats. OBJECTIVE: To further test this hypothesis, in the present paper we examined the effect of surgical removal of perirenal and epididymal WAT on serum leptin concentration and lipogenic enzymes activities in remnant adipose tissue of old rats. METHODS: One-year-old rats, which display a high serum leptin concentration and low lipogenic enzyme activities in WAT, were subjected to surgical removal of the perirenal and epididymal WAT. Two months after the surgery, the serum leptin concentration and lipogenic enzyme activities in remnant WAT were compared to the serum leptin concentration and lipogenic enzyme activities measured in adipose tissue collected during the surgery. RESULTS: WAT removal resulted in an approximately 6-fold decrease of serum leptin concentration and about a 2-fold increase of lipogenic enzyme activities in remnant adipose tissue. CONCLUSIONS: These results indicate that interventions designed to reduce abdominal adipose tissue mass can change the lipogenic activity of remnant adipose tissue. Additionally, leptin could be one of the factors contributing to the downregulation of the genes expression of lipogenic enzymes during ageing in rats.