Increases in systemic and local stress: a probable mechanism of visceral fat accumulation and insulin resistance in adult catch-up growth rats?

Catch-up growth in adult (CUGA) is increasingly proposed as an important causative factor for the widespread insulin resistance (IR)-related diseases especially in developing countries/territories. We aimed to investigate the effects of CUGA to insulin sensitivity, lipid profile and stress in rats, as well as the probable relationship among them. Male Sprague-Dawley rats were randomly divided into six groups for two sampling points: caloric restriction group (R4) and normal chow controls for four weeks (NC4); CUGA re-fed with normal chow (RN4), CUGA re-fed with high-fat diet (RH4), normal chow controls (NC8) and high-fat diet controls (HF8) for eight weeks. Visceral fat accumulation (visceral adipose tissue [VAT] percentage), systemic (plasma corticosterone) and local (HSD11B1 mRNA expression in skeletal muscle [SkM] and VAT) stress, whole-body and peripheral insulin sensitivity were determined in this study. After four weeks of caloric restriction, R4 rats showed increases in systemic and local stress, decreases in visceral fat accumulation and no IR (whole-body or peripheral). Yet, after re-feeding, sustained systemic and local stress, remarkable visceral fat accumulation and IR (whole-body and peripheral) were found in RN4 compared with NC8, in RH4 compared with NC8 and HF8. Our findings demonstrated that CUGA rats were characterized by significant IR, visceral fat accumulation and stress. These changes were more severe in CUGA re-fed with high-fat diet. The interaction of sustained caloric restriction-induced stress and re-feeding might be of utmost importance in the etiology of visceral fat accumulation and IR in CUGA.