Dietary fat source regulates ob gene expression in white adipose tissue of rats under hyperphagic feeding

Abstract

This work was designed to investigate the effect of different lipid sources on ob gene expression and serum leptin levels in rats with two different feeding protocols: (1) free access to food; or (2) energy-controlled feeding. Male Wistar rats were fed diets containing 40 % energy as fat (olive oil, sunflower oil or beef tallow), for 4 weeks. In Expt 1 rats had free access to food, and in Expt 2 rats were fed a controlled amount of food (16 g/d, equivalent to 300 kJ/d). Insulin and leptin were determined by ELISA and ob mRNA by Northern blot. When rats had free access to food, ob mRNA levels were higher in animals fed either olive oil or sunflower oil than in those fed beef tallow. In marked contrast with feeding ad libitum, no differences were found among dietary fat groups in rats fed energy-controlled diets. When both feeding protocols were compared, free access to food induced an increased expression of ob mRNA in perirenal and/or epididymal adipose tissues from rats fed either olive oil or sunflower oil, but not from rats fed beef tallow. Dietary lipid type did not induce modifications in serum leptin concentrations. A tendency to higher serum leptin levels was observed more in rats with free access to food than in rats fed energy-controlled feeding. No differences were found in insulin levels. Dietary fat type importantly affects ob mRNA expression in rat white adipose tissue under hyperphagic conditions. Further study is needed in order to elucidate the mechanism underlying this effect.

Lipid Droplet-Derived Monounsaturated Fatty Acids Traffic via PLIN5 to Allosterically Activate SIRT1

“…MUFAs are common in many foods but are enriched in a variety of foods including nuts, avocados, and olive oil. Evidence from model organism studies through clinical trials bear out the effects of MUFAs and/or olive oil on improvements in oxidative metabolism and energy expenditure (Børsheim et al, 2006;Rodrı ´guez et al, 2002;Shin and Ajuwon, 2018) and in disease prevention and lifespan extension (Buckland and Gonzalez, 2015;Estruch et al, 2006;Han et al, 2017;Salas-Salvado ´et al, 2011;Hoffmann, 2014a, 2014b;Schwingshackl et al, 2011;Trichopoulou et al, 2005). Importantly, MUFAs are regarded as one of the key components of the Mediterranean Diet, which is well established to have wide-ranging health benefits including reduced agingrelated diseases and overall mortality (Sofi et al, 2010).…”

Monounsaturated n-9 fatty acids and adipocyte lipolysis in rats

“…This suggests a new form of leptin-mediated lipolysis. The possibility cannot be ruled out that the n-9 fatty acids induce a modification of leptin metabolism and that, either alone or interacting with lipolytic hormones, they can modify lipolytic activity (Rodríguez et al 2002a). Greater accumulations of adipose tissue can increase the levels of circulating leptin, which in turn would increase adipose tissue lipolytic activity (Martínez et al 2000).…”

The role of dietary fat in adipose tissue metabolism

“…Fatty acids may influence the expression of adipokines like leptin and resistin directly by interaction with transcription factors, or indirectly via unknown mechanisms possibly linked to fatty acid oxidation, synthesis or storage 39 . It has been reported that dietary monounsaturated and polyunsaturated fatty acids may modify plasma leptin concentration in human, rat and mice, by means of a decrease in leptin gene expression both in vivo and in vitro , mediated by mechanisms associated with reduced PPARγ and SREBP-1 gene expression 40 , 41 . Moreover, it has been shown that resistin is inhibited by polyunsaturated fatty acids.…”