Feed withdrawal abate regimens lipodystrophy and metabolic syndrome symptoms, such as glucose tolerance, are associated with the diameter of retroperitoneal adipocytes in rats

Adipocyte numbers were increased by feed withdrawal (FW) regimens in cattle; thus, the effect of FW regimens was studied in male Wistar and fa/fa obese rats, as models for humans, in 2 completely randomized design experiments to abate lipodystrophy and progression of metabolic syndrome symptoms. The hypothesis was that application of FW regimens could alter adipose tissue cellularity, adipocyte size, and affect area under the curve (AUC) during glucose tolerance tests. Objectives were to determine associations among retroperitoneal and inguinal adipose tissue adipocyte number, diameter, and AUC, as affected by fortnightly or a single (at age 50 days) 24-hour FW regimen. Adipocyte marker peroxisome proliferator-activated receptor γ expression was elevated (P = .054) in the retroperitoneal tissue of fa/fa obese rats in the fortnightly FW treatment because of a 13% increase in tissue cell density (cells per gram; P = .13). Average cell diameter in retroperitoneal adipose and AUC were negatively corelated. Regression analyses after including the square of average cell diameter indicated that average retroperitoneal adipocyte diameter (between 65 and 135 μm) and the AUC were related in a quadratic manner (R2 = 0.14; n = 49; P = .03) for Wistar rats. Cell number of the inguinal and retroperitoneal adipocytes tended to be positively corelated (r = 0.24; P = .09 and r = 0.26; P = .07, n = 49, respectively) to the AUC and are indexes of adiposity. Results suggest that maintenance of retroperitoneal adipocytes at appropriate diameters may control progression of metabolic syndrome symptoms such as glucose tolerance. © 2010.