Impact of Dietary FA and Energy Restriction on Plasma Leptin and ob Gene Expression in Mice

Abstract

The aim of the present study was to elucidate whether the qualitative composition of dietary fat influences plasma leptin and adipose tissue ob gene expression differentially. Two high-fat diets and a diet rich in carbohydrate were each administered both ad libitum and with a 25% energy restriction. The high-fat diets contained 58 energy percent as either monounsaturated FA (MUFA) or saturated FA (SAFA), whereas the carbohydrate-rich diet (CH) contained 7 energy percent as fat. We aimed at obtaining the same final weight for the animals in the ad libitum group as in the energy-restricted groups. This goal was reached at the same time (days 22-24) for all groups except for the ad libitum animals fed on saturated fat (day 36). The plasma leptin concentrations on ad libitum CH and MUFA diets did not differ significantly (24.3 +/- 2.1 and 34.7 +/- 6.7 ng/mL, respectively) whereas the saturated fat diet caused a lower concentration (13.9 +/- 1.9 ng/mL; P < 0.05). Interestingly, no differences in plasma leptin levels between groups were seen in the energy-restricted groups (mean 8.0 +/- 1.0 ng/mL). The type of diet did not alter the ob gene expression in intraabdominal white adipose tissue; however, a lower expression level was found in the energy-restricted groups. The percentage of body fat in the three ad libitum fed groups did not differ (23 +/- 1%). Thus, short-term administration of a diet rich in SAFA suppresses circulating leptin levels without altering the adipose tissue ob gene expression. This indicates that saturated fat may alter protein handling by adipose tissue or the whole body clearance of leptin.

Plasma leptin levels in pigs with different leptin and leptin receptor genotypes

“…Our main goal was to investigate if there are differences in plasma Lep levels amongst pig Lep and Lepr genotypes to gain new insights into the molecular basis of the phenotypic associations reported in the literature. The mean levels of plasma leptin we have found in our Landrace population were slightly higher than the ones reported in other studies (Barb et al 2001;Estienne et al 2003), but they are completely consistent with what has been published in human (Sone & Osamura 2001, mean plasma leptin concentration: 8 ng ⁄ ml), mouse (Gregersen et al 2003), dog (Sagawa et al 2002) and cat (Shibata et al 2003). This discrepancy between our and previous studies focused on pigs might be explained by (i) the existence of a significant variation in plasma Lep levels amongst pig populations, as reported by Berg et al (2003) and (ii) the fact that we have measured Lep levels with ELISA whereas previous studies employed a radioimmunoassay technique.…”

“…2001; Estienne et al. 2003), but they are completely consistent with what has been published in human (Sone & Osamura 2001, mean plasma leptin concentration: 8 ng/ml), mouse (Gregersen et al. 2003), dog (Sagawa et al.…”

Intermittent Fasting Ameliorates Delayed-Type Hypersensitivity in NC/Nga Mice

“…Another factor which controls starvation-induced lymphoid atrophy is leptin. Previously, Lord et al [12] demonstrated that administration of leptin, which is acknowledged to decrease by fasting or DR [12,[24][25][26], to fasted mice reversed the immunosuppressive effects of fasting on DTH. Furthermore, Howard et al [18] have shown that exogenous leptin, administered only during the period of fasting, was able to protect completely against the thymic atrophy induced by acute starvation.…”