Endurance Training Increases Leptin Expression in the Retroperitoneal Adipose Tissue of Rats Fed with a High‐Sugar Diet

Abstract

The presence of leptin receptors in white adipose tissue (WAT) suggests a type of peripheral control during the development of obesity and other metabolic disorders. Both diet composition and exercise influence serum leptin; however, the effect of their combination on long-term WAT leptin metabolism is unknown. In this study, rats fed with standard or high-sugar diets (HSD) were simultaneously subjected to running training for 4- and 8-week periods, and the retroperitoneal WAT (rWAT) was evaluated for adipocyte cell size, lipid and catecholamine content, Lep, OB-Rb and Ucp2 mRNA transcription levels, and circulating leptin and non-esterified fatty acids (NEFA). The HSD groups displayed a higher adiposity index and rWAT weight, Lep mRNA and protein upregulation, and a period-dependent effect on OB-Rb mRNA expression. Exercise decreased serum leptin and upregulated the OB-Rb mRNA levels. However, in rats fed with an HSD, the increase in OB-Rb mRNA and reduction in catecholamine levels resulted in a high level of adiposity and hyperleptinemia. The combination of training and an HSD decreases the NEFA levels and upregulating the Ucp2 mRNA expression in the 4-week period, while downregulating the Ucp2 mRNA expression in the 8-week period without changing the NEFA levels. Our results suggest that an HSD induces an increase in leptin expression in rWAT, while reducing adipocytes via leptin-mediated lipolysis after an 8-week period. In exercised rats fed an HSD, TAG synthesis and storage overlaps with lipolysis, promoting fat store development and Lep mRNA and plasma protein upregulation in adult rats.

Molecular mechanism driving retroperitoneal adipocyte hypertrophy and hyperplasia in response to a high‐sugar diet

“…In addition, the overconsumption of high‐carbohydrate diets modulates cellular pathways controlling de novo lipogenesis, leading to greater adiposity . Although their final body weights were identical, we demonstrated that the corporal composition was different in rats fed a HSD, with increasing fat mass according to previous results from our group . In a study conducted by de Lima et al.…”

“…In addition, the overconsumption of high-carbohydrate diets modulates cellular pathways controlling de novo lipogenesis, leading to greater adiposity [13]. Although their final body weights were identical, we demonstrated that the corporal composition was different in rats fed a HSD, with increasing fat mass according to previous results from our group [26,29]. In a study conducted by de Lima et al [7], an increase in the Lee index was observed after a 19-week HSD feeding period in the same experimental model; however, the time point that these alterations began remained unclear.…”

“…However, excessive intake of simple carbohydrates throughout this period could alter the expression of genes acting in networks related to cell differentiation and lipid metabolism in adipose tissue, increasing the prevalence of cardiovascular and metabolic diseases later in life [1]. Previous results from our group have suggested that a HSD induces an increase in leptin expression in rWAT, with OB-Rb mRNA down-regulation after an 8-week period and promotes triacylglicerol synthesis and storage, culminating in high levels of serum leptin [26]. In the present study, we examined the expression profile of 84 key genes involved in the differentiation and maintenance of mature adipocytes using a Rat Adipogenesis PCR array to determine the inherent signalling mechanisms related to morphological changes in rWAT.…”

Citrulline reduces glyceroneogenesis and induces fatty acid release in visceral adipose tissue from overweight rats

“…The excessive development of visceral white adipose tissue (AT) is an important determinant of metabolic syndrome, a complication that frequently occurs in obese subjects [6]. Among the intra-abdominal depots, epididymal (EPI) and retroperitoneal (RET) AT are considered as visceral depots and have been largely used for metabolic regulation studies [7][8][9][10][11].…”

Circulating Concentrations of Adipocytokines and Their Receptors in the Isolated Corpus Cavernosum and Femoral Artery from Trained Rats on a High-Fat Diet

“…The contributions of exercise training towards reducing circulating adipocytokine levels may be important to other tissue responses, but the effects of ObR on vascular tissue in exercised animals are unknown since most studies examined the effect of exercise training on leptin and its receptors in adipose tissue and skeletal muscle [79,80]. In addition, a reduction in AdipoR1 has been reported in skeletal muscle and adipose tissue in experimental models of obesity, and exercise training was effective to prevent this alteration [81,82].…”