Fig. 6.
The change in adipocyte cell size frequency distribution with weight loss and weight regain. Data from our published weight regain studies in DIO rats (108, 148, 151), as well as ongoing studies, were examined in a combined analysis of retroperitoneal adipocyte cellularity characteristics. In all, the analysis included 21,710 adipocytes from 115 animals at the specified stages of the weight regain process. Cell size frequency distributions, with the effect on average cell size and total number of cells in the depot, are shown for the sequential steps of loss and regain: weight loss and long term (>8 wk) maintenance (A), after the first few days of weight regain (B), after relapse continues into the second week of weight regain (C), and after surpassing their preweight loss weight (D). E: when relapse animals are compared again to obese rats that never lost weight, they have more cells and still have a smaller average size. The profile shift at each stage of weight loss and regain, indicated with dotted arrows, is statistically significant (χ2 analysis, P < 0.05).