Morphological and metabolic alterations in adipose tissue of very old rats

Body weight, epididymal adipose tissue weight, fat cell size, and metabolic activity of fat depot were studied in 30-month-old Wistar rats and compared with rats aged 6 and 24 months old. In very old age a significant reduction of body weight was observed and was paralleled with a decline of adipose mass and a decrease in cell volume. In vitro metabolic studies, with and without insulin, showed a greater oxidation of D-U-14C glucose to 14CO2 and a greater incorporation into triglycerides than in the 24-month-old animals when the data were expressed per cell or per cm2 surface area. The resistance to insulin was elevated in spite of a significant decrease of adipocyte size in very old rats.