The futile creatine cycle and the synthesis of fatty acids in inguinal white adipose tissue from growing rats, submitted to a hypoprotein-hyperglycidic diet for 15 days.

The low-protein, high-carbohydrate (LPHC) diet administered to growing rats soon after weaning, for 15 days, promoted an increase in energy expenditure by uncoupling protein 1 (UCP1) in interscapular brown adipose tissue, and also due to the occurrence of the browning process in the perirenal white adipose tissue (periWAT). However, we believe that inguinal white adipose tissue (ingWAT) may also contribute to energy expenditure through other mechanisms. Therefore, the aim of this work is to investigate the presence of the futile creatine cycle, and the origin of lipids in ingWAT, since that tissue showed an increase in the lipids content in rats submitted to the LPHC diet for 15 days. We observed increases in creatine kinase and alkaline phosphatase activity in ingWAT, of the LPHC animals. The mitochondrial Nicotinamide adenine dinucleotide reduced/nicotinamide adenine dinucleotide oxidized ratio is lower in ingWAT of LPHC animals. In the LPHC animals treated with ß-guanidinopropionic acid, the extracellular uptake of creatine in ingWAT was lower, as was the rectal temperature. Regarding lipid metabolism, we observed that in ingWAT, lipolysis in vitro when stimulated with noradrenaline is lower, and there were no changes in baseline levels. In addition, increases in the activity of enzymes were also observed: malic, glucose-6-phosphate dehydrogenase, and ATP-citrate lyase, in addition to an increase in the PPARγ content. The results show the occurrence of the futile creatine cycle in ingWAT, and that the increase in the relative mass may be due to an increase in de novo fatty acid synthesis.

Introduction of high-fat and very-high-fat diets associated with fructose drink in critical development periods causes cardiovascular damage in rats at the beginning of adult life.

OBJECTIVES: Exposure to an obesogenic environment at critical stages of human development may lead to cardiovascular damage during early adulthood, such as left ventricular hypertrophy (LVH). The objective of this study is to investigate whether the consumption of diets with different levels of fat associated with fructose drink, introduced to newly weaned rats, leads to cardiovascular damage. METHODS: Male Wistar rats (age 21 d) were divided into the following groups: Control (C group) fed an American Institute of Nutrition 93G diet (16.3 % kcal of lipid); high-fat diet (HF group: 45% kcal of lipids), and very-high-fat diet (VHF group: 60% kcal of lipids). The HF and VHF groups also received a fructose solution (10%) for hydration. RESULTS: After 70 d, the animals in the HF and VHF groups presented with cardiovascular damage as a comorbidity of obesity, with increased creatine kinase-MB levels, high heart and left ventricle (LV) mass, and an increase in the LV:tibia ratio. The positive correlation was observed between serum leptin levels and LV mass. In addition, the signal transducer and activator of transcription 3 content in LV was lower. CONCLUSIONS: The administration of diets with different fat and carbohydrate contents associated with fructose drinks introduced to newly weaned rats leads to LVH during early adulthood. The data suggest that the change in leptin-signal transducer and activator of transcription 3 pathway signaling in the groups is related to the occurrence of LVH.