PPARgamma activity in subcutaneous abdominal fat tissue and fat mass gain during short-term overfeeding

The interplay of mitophagy, autophagy, and apoptosis in cisplatin-induced kidney injury: involvement of ERK signaling pathway

AKI induced by CP chemotherapy remains an obstacle during patient treatments. Extracellular signal-regulated protein kinases 1/2 (ERK), key participants in CP-induced nephrotoxicity, are suggested to be involved in the regulation of mitophagy, autophagy, and apoptosis. Human renal proximal tubular cells (HK-2) and BALB/cN mice were used to determine the role of ERK in CP-induced AKI. We found that active ERK is involved in cell viability reduction during apoptotic events but exerts a protective role in the early stages of treatment. Activation of ERK acts as a maintainer of the mitochondrial population and is implicated in mitophagy initiation but has no significant role in its conduction. In the late stages of CP treatment when ATP is deprived, general autophagy that requires ERK activation is initiated as a response, in addition to apoptosis activation. Furthermore, activation of ERK is responsible for the decrease in reserve respiratory capacity and controls glycolysis regulation during CP treatment. Additionally, we found that ERK activation is also required for the induction of NOXA gene and protein expression as well as FoxO3a nuclear translocation, but not for the regular ERK-induced phosphorylation of FoxO3a on Ser294. In summary, this study gives detailed insight into the involvement of ERK activation and its impact on key cellular processes at different time points during CP-induced kidney injury. Inhibitors of ERK activation, including Mirdametinib, are important in the development of new therapeutic strategies for the treatment of AKI in patients receiving CP chemotherapy.

Leptin-A Potential Bridge between Fat Metabolism and the Brain's Vulnerability to Neuropsychiatric Disorders: A Systematic Review

BACKGROUND

Obesity and being overweight have been described as potential causes of neurological disorders. Leptin, a peptide expressed in fat tissue, importantly participates in energy homeostasis and storage and has recently been identified for its signaling receptors in neuronal circuits of the brain.

AIM

To elucidate whether the endogenous modulation of leptin can be a protection against neuropsychiatric disorders.

METHOD

A systematic review was performed in accordance with the PRISMA-P method, and reports of studies containing data of leptin concentrations in healthy individuals with or without obesity were retrieved from the PubMed database, using the combinations of Mesh terms for "Leptin" and "Metabolism".

RESULTS

Forty-seven randomized and non-randomized controlled trials, dating from 2000 to 2021, were included in the qualitative synthesis.

DISCUSSION AND CONCLUSIONS

Leptin secretion displays a stabilizing pattern that is more sensitive to a negative energy intake imbalance. Leptin levels influence body weight and fat mass as a pro-homeostasis factor. However, long-term exposure to elevated leptin levels may lead to mental/behavioral disorders related to the feeding and reward systems.

Effect of Vitamin E on Serum Levels of Vascular Endothelial Growth Factor and Angiopoietin-1 in Women with Polycystic Ovary Syndrome: A Pilot Randomized, Placebo-Controlled Trial

Background

Angiogenesis disturbances are common in women with polycystic ovary syndrome (PCOS). Vitamin E has antiangiogenic properties. Data on the effects of vitamin E on angiogenesis in PCOS is limited, so the current study was conducted to evaluate its effects on angiogenic indices in PCOS patients.

Materials and Methods

This randomized, double-blind, placebo-controlled trial was performed on 43 women aged 20-40 years, diagnosed with PCOS (Rotterdam criteria). It was performed at the referral clinic affiliated to Tabriz University of Medical Sciences, Tabriz, Iran, from April 2017 to September 2017. Patients were randomly assigned into two groups to receive either 400 IU/day vitamin E -as alpha tocopheryl acetate- (n=22) or placebo (n=21), for 8 weeks. Anthropometric, and angiogenic parameters including body weight, fat mass and fat free mass, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), angiopoietin-1 (Ang- 1), and angiopoietin-2 (Ang-2) were measured by standard methods at the beginning and at the end of study. Statistical Package for Social Science version 25 was used for statistical analysis and P<0.05 were considered significant.

Results

After adjusting for potential confounders, we observed that vitamin E supplementation significantly reduced body weight, fat mass, Ang-1, Ang-1/Ang-2 ratio and VEGF (P<0.01). We did not observe any considerable effect for vitamin E on Ang-2 level or bFGF.

Conclusion

Vitamin E supplementation for 8 weeks in the PCOS women had beneficial effects on body weight, Ang- 1, Ang-1/Ang-2 ratio, and VEGF level (Registration number: IRCT201610193140N18).

Prenatal Hyperglycemia Exposure and Cellular Stress, a Sugar-Coated View of Early Programming of Metabolic Diseases

Worldwide, the number of people with diabetes has quadrupled since 1980 reaching 422 million in 2014 (World Health Organization). This distressing rise in diabetes also affects pregnant women and thus, in regard to early programming of adult diseases, creates a vicious cycle of metabolic dysfunction passed from one generation to another. Metabolic diseases are complex and caused by the interplay between genetic and environmental factors. High-glucose exposure during in utero development, as observed with gestational diabetes mellitus (GDM), is an established risk factor for metabolic diseases. Despite intense efforts to better understand this phenomenon of early memory little is known about the molecular mechanisms associating early exposure to long-term diseases risk. However, evidence promotes glucose associated oxidative stress as one of the molecular mechanisms able to influence susceptibility to metabolic diseases. Thus, we decided here to further explore the relationship between early glucose exposure and cellular stress in the context of early development, and focus on the concept of glycemic memory, its consequences, and sexual dimorphic and epigenetic aspects.

The biology of human overfeeding: A systematic review

This systematic review has examined more than 300 original papers dealing with the biology of overfeeding. Studies have varied from 1 day to 6 months. Overfeeding produced weight gain in adolescents, adult men and women and in older men. In longer term studies, there was a clear and highly significant relationship between energy ingested and weight gain and fat storage with limited individual differences. There is some evidence for a contribution of a genetic component to this response variability. The response to overfeeding was affected by the baseline state of the groups being compared: those with insulin resistance versus insulin sensitivity; those prone to obesity versus those resistant to obesity; and those with metabolically abnormal obesity versus those with metabolically normal obesity. Dietary components, such as total fat, polyunsaturated fat and carbohydrate influenced the patterns of adipose tissue distribution as did the history of low or normal birth weight. Overfeeding affected the endocrine system with increased circulating concentrations of insulin and triiodothyronine frequently present. Growth hormone, in contrast, was rapidly suppressed. Changes in plasma lipids were influenced by diet, exercise and the magnitude of weight gain. Adipose tissue and skeletal muscle morphology and metabolism are substantially altered by chronic overfeeding.

Molecular adaptation in adipose tissue in response to overfeeding with a high-fat diet under sedentary conditions in South Asian and Caucasian men

For the same BMI, South Asians have a higher body fat percentage than Caucasians. There might be differences in the fatty acid (FA) handling in adipose tissue when both ethnicities are exposed to high-fat overfeeding. The objective of the present study was to investigate the molecular adaptation in relation to FA metabolism in response to overfeeding with a high-fat diet (OHFD) in South Asian and Caucasian men. Ten South Asian men (BMI 18-29 kg/m2) and ten Caucasian men (BMI 22-33 kg/m2), matched for body fat percentage, aged 20-40 years were included. A weight-maintenance diet (30 % fat, 55 % carbohydrate and 15 % protein) was given for 3 d followed by 3 d of overfeeding (150 % energy requirement) with a high-fat diet (60 % fat, 25 % carbohydrate and 15 % protein) while staying in a respiration chamber. Before and after overfeeding, abdominal subcutaneous fat biopsies were taken. Proteins were isolated, analysed and quantified for short-chain 3-hydroxyacyl-CoA dehydrogenase (HADH), carnitine palmitoyl-transferase 1α (CPT1a), adipose TAG lipase, perilipin A (PLINA), perilipin B, lipoprotein lipase and fatty acid binding protein 4 using Western blotting. OHFD decreased the HADH level (P < 0·05) in Caucasians more than in Asians (P < 0·05), but the baseline and after intervention HADH level was relatively higher in Caucasians. The level of CPT1a decreased in South Asians and increased in Caucasians (P < 0·05). PLINA did not change with diet but the level was higher in South Asians (P < 0·05). The observed differences in HADH and PLINA levels as well as in CPT1a response may be important for differences in the long-term regulation of energy (fat) metabolism in these populations.

Substrate utilization and metabolic profile in response to overfeeding with a high-fat diet in South Asian and white men: a sedentary lifestyle study

BACKGROUND

For the same BMI, South Asians have a higher body fat percentage, a higher liver fat content and a more adverse metabolic profile than whites. South Asians may have a lower fat oxidation than whites, which could result in an unfavorable metabolic profile when exposed to increased high-fat foods consumption and decreased physical activity as in current modern lifestyle.

OBJECTIVE

To determine substrate partitioning, liver fat accumulation and metabolic profile in South Asian and white men in response to overfeeding with high-fat diet under sedentary conditions in a respiration chamber.

DESIGN

Ten South Asian men (BMI, 18-29 kg/m²) and 10 white men (BMI, 22-33 kg/m²), matched for body fat percentage, aged 20-40 year were included. A weight maintenance diet (30% fat, 55% carbohydrate, and 15% protein) was given for 3 days. Thereafter, a baseline measurement of liver fat content (1H-MRS) and blood parameters was performed. Subsequently, subjects were overfed (150% energy requirement) with a high-fat diet (60% fat, 25% carbohydrate, and 15% protein) over 3 consecutive days while staying in a respiration chamber mimicking a sedentary lifestyle. Energy expenditure and substrate use were measured for 3 × 24-h. Liver fat and blood parameters were measured again after the subjects left the chamber.

RESULTS

The 24-h fat oxidation as a percentage of total energy expenditure did not differ between ethnicities (P = 0.30). Overfeeding increased liver fat content (P = 0.02), but the increase did not differ between ethnicities (P = 0.64). In South Asians, overfeeding tended to increase LDL-cholesterol (P = 0.08), tended to decrease glucose clearance (P = 0.06) and tended to elevate insulin response (P = 0.07) slightly more than whites.

CONCLUSIONS

Despite a similar substrate partitioning and similar accretion of liver fat, overfeeding with high-fat under sedentary conditions tended to have more adverse effects on the lipid profile and insulin sensitivity in South Asians.

Modulation of hyperglycemia and dyslipidemia in experimental type 2 diabetes by gallic acid and p-coumaric acid: The role of adipocytokines and PPARγ

There are many indications that confirm the vital role of adipocytokines and PPARγ in diabetics. Hence, the current investigation aimed to study the modulatory effects of gallic acid and p-coumaric acid on adipocytokines secretion and PPARγ mRNA expression in type 2 diabetic rats. After induction of type 2 diabetes, diabetic rats were orally treated with 20 mg/kg body mass gallic acid and 40 mg/kg body mass p-coumaric acid for six weeks. Among treatment diabetic rats, glucose and glycosylated hemoglobin levels significantly declined in diabetic rats, while insulin level and body weight significantly increased as compared to control group. Gallic acid and p-coumaric acid markedly decreased the level of TNF-α and increased the levels of PPARγ mRNA and adiponectin. In addition, the tested agents improved markedly lipid profile parameters, cardiovascular indices 1 and 2 and anti-atherogenic index. In conclusion, gallic acid and p-coumaric acid exhibited marked antidiabetic action that could be mediated via modulation of TNF-α and adipocytokines secretions as well as upregulation of PPARγ mRNA expression.

Liver fat accumulation in response to overfeeding with a high-fat diet: a comparison between South Asian and Caucasian men

Background

South Asians were reported to have a higher liver fat content as compared to BMI-matched Caucasians. This study compared the increase in liver fat content in response to overfeeding with a high fat diet in South Asian and Caucasian men when matched for body fat percentage.

Methods

Ten South Asian men (BMI 18–29 kg/m²) and 10 Caucasian men (BMI 22–33 kg/m²), aged 20–40 y, matched for body fat percentage, were included. A weight maintenance diet was given for 3 days based on the individual energy requirement. Individual energy requirement of the subjects was calculated based on their body composition (measured by hydro densitometry and deuterium dilution) and activity counts (accelerometer). Liver fat content was measured before and after 4 days of overfeeding (50 % excess energy need) with a high fat diet (60 % energy from fat). Fat distribution was measured by anthropometry and an MRI scan of the abdomen while liver fat content using 1H-MRS.

Results

While having a similar body fat % (P = 0.58), South Asians had a lower BMI (P = 0.04) than Caucasians. Liver fat content at baseline did not differ between ethnicities (P = 0.48) and was associated with visceral fat area (P = 0.002, R² = 0.56) but not with ethnicity (P = 0.13). Overfeeding with a high fat diet significantly increased liver fat (P = 0.01) but the increase did not differ between ethnicities (P = 0.47). There was no difference in the total abdominal fat area (P = 0.37), subcutaneous abdominal fat area (P = 0.18) and visceral fat area (VAT, P = 0.32). However as a percentage of the total abdominal fat area, VAT was higher in South Asians (P = 0.003).

Conclusion

Despite a relatively higher percentage of visceral fat area, liver fat increased similarly in South Asian and Caucasian men in response to overfeeding with a high fat diet.

Trial registration

The study was registered in the public trial registry www.ccmo.nl No. NL31217.068.10.

X-box binding protein 1 is a novel key regulator of peroxisome proliferator-activated receptor γ2

X-box binding protein 1 (XBP1), a transcription factor of the unfolded protein response, plays various roles in many biological processes. We examined its pro-adipogenic activity and target genes during adipogenic differentiation in wild-type and genetically modified 3T3-L1 cells. Signalling pathways that contribute to Xbp1 mRNA splicing, and the correlation of the transcriptionally active XBP1 isoform (XBP1s) level with body mass index and the level of peroxisome proliferator-activated receptor γ2 (PPARγ2) in human adipose tissues were also examined. The mRNA and nuclear protein expression levels of XBP1s increased immediately following hormonal induction of adipogenesis, reaching a peak at 6 h. Results from cDNA microarray and gene expression analyses using genetically modified cells indicated that PPARγ2 was a principal target of XBP1s. The XBP1s-specific binding motif, which is distinct from the CCAAT/enhancer-binding protein α binding site, was identified in the PPARγ2 promoter by site-directed mutagenesis. Fetal bovine serum, insulin, 3-isobutyl-1-methylxanthine and dexamethasone contributed independently to Xbp1 mRNA splicing. In human subcutaneous adipose tissues, the levels of both Xbp1s and Pparγ2 mRNA increased proportionally with body mass index, and there was a significant positive correlation between the two genes. These data suggest for the first time that positive regulation of PPARγ2 is a principal mechanism of XBP1s-mediated adipogenesis in 3T3-L1 cells.

Reduced cellular Mg²⁺ content enhances hexose 6-phosphate dehydrogenase activity and expression in HepG2 and HL-60 cells

We have reported that Mg(2+) dynamically regulates glucose 6-phosphate entry into the endoplasmic reticulum and its hydrolysis by the glucose 6-phosphatase in liver cells. In the present study, we report that by modulating glucose 6-phosphate entry into the endoplasmic reticulum of HepG2 cells, Mg(2+) also regulates the oxidation of this substrate via hexose 6-phosphate dehydrogenase (H6PD). This regulatory effect is dynamic as glucose 6-phosphate entry and oxidation can be rapidly down-regulated by the addition of exogenous Mg(2+). In addition, HepG2 cells growing in low Mg(2+) show a marked increase in hexose 6-phosphate dehydrogenase mRNA and protein expression. Metabolically, these effects on hexose 6-phosphate dehydrogenase are important as this enzyme increases intra-reticular NADPH production, which favors fatty acid and cholesterol synthesis. Similar effects of Mg(2+) were observed in HL-60 cells. These and previously published results suggest that in an hepatocyte culture model changes in cytoplasmic Mg(2+) content regulates glucose 6-phosphate utilization via glucose 6 phosphatase and hexose-6 phosphate dehydrogenase in alternative to glycolysis and glycogen synthesis. This alternative regulation might be of relevance in the transition from fed to fasted state.

Metabolic profile before and after short-term overfeeding with a high-fat diet: a comparison between South Asian and White men

For the same BMI, South Asians have a higher body fat percentage and an adverse metabolic profile compared with whites. The objective of the present study was to determine the metabolic profiles of South Asian and white men matched for body fat percentage in response to short-term overfeeding with a high-fat diet. A total of ten healthy non-diabetic South Asian men matched for body fat percentage with ten white men were included in the study. A weight-maintenance diet (containing 30 % fat, 55 % carbohydrate and 15 % protein) was provided for 3 d followed by 4 d of overfeeding (150 % of energy requirement) with a high-fat diet (60 % fat, 25 % carbohydrate and 15 % protein). Before and after the overfeeding period, plasma glucose, insulin, TAG, NEFA, total cholesterol and HDL-cholesterol concentrations were determined. Glucose clearance was calculated using a 2 h oral glucose tolerance test. The results revealed that in South Asian and white men, respectively, overfeeding with a high-fat diet decreased plasma TAG concentrations by 0·4 (sd 0·6) and 0·4 (sd 0·5) mmol/l (P diet= 0·008; P ethnicity= 0·24), increased HDL-cholesterol concentrations by 0·12 (sd 0·1) and 0·14 (sd 0·2) mmol/l (P diet= 0·001; P ethnicity= 0·06) and decreased glucose clearance by 48·8 (sd 53·5) and 37·2 (sd 34·2) ml/min per m2 body surface (P diet= 0·004; P ethnicity= 0·18). There was a significant interaction between diet and ethnicity with regard to the changes in total and LDL-cholesterol concentrations (P= 0·01 and 0·007, respectively), which trended towards a larger increase in South Asian subjects than in white subjects. Despite a similar body fat percentage, short-term overfeeding with a high-fat diet had more adverse effects on the lipid profile of South Asians than on that of whites.

Obesity, adiposity, and dyslipidemia: a consensus statement from the National Lipid Association

The term "fat" may refer to lipids as well as the cells and tissue that store lipid (ie, adipocytes and adipose tissue). "Lipid" is derived from "lipos," which refers to animal fat or vegetable oil. Adiposity refers to body fat and is derived from "adipo," referring to fat. Adipocytes and adipose tissue store the greatest amount of body lipids, including triglycerides and free cholesterol. Adipocytes and adipose tissue are active from an endocrine and immune standpoint. Adipocyte hypertrophy and excessive adipose tissue accumulation can promote pathogenic adipocyte and adipose tissue effects (adiposopathy), resulting in abnormal levels of circulating lipids, with dyslipidemia being a major atherosclerotic coronary heart disease risk factor. It is therefore incumbent upon lipidologists to be among the most knowledgeable in the understanding of the relationship between excessive body fat and dyslipidemia. On September 16, 2012, the National Lipid Association held a Consensus Conference with the goal of better defining the effect of adiposity on lipoproteins, how the pathos of excessive body fat (adiposopathy) contributes to dyslipidemia, and how therapies such as appropriate nutrition, increased physical activity, weight-management drugs, and bariatric surgery might be expected to impact dyslipidemia. It is hoped that the information derived from these proceedings will promote a greater appreciation among clinicians of the impact of excess adiposity and its treatment on dyslipidemia and prompt more research on the effects of interventions for improving dyslipidemia and reducing cardiovascular disease risk in overweight and obese patients.

Dietary fat oxidation as a function of body fat

PURPOSE OF REVIEW

Is trafficking of dietary fat involved in the development of obesity?

RECENT FINDINGS

Studies on energy expenditure and substrate utilization during overfeeding, studies on individual differences in substrate utilization between individuals fed at energy balance, and differences in responses in energy expenditure and substrate utilization in individuals after weight reduction, illustrate that the capacity of fat oxidation is a potential determinant for the development of obesity.

SUMMARY

The ability to store dietary fat seems to be involved in the susceptibility to gain weight during a positive energy balance. Obese individuals show less oxidation and more storage of dietary fat as compared with the lean phenotype. Differences in fuel trafficking make individuals prone to overeating in the current obesogenic environment with a high availability of energy-dense fatty foods. It is difficult to get rid of excess body fat as energy requirement for weight maintenance after weight reduction is lower than predicted from the new body composition reached and thus, there is a high risk for weight regain.

Fatty acid binding proteins in adipose tissue: a promising link between metabolic syndrome and atherosclerosis?

Adipocyte/macrophage fatty acid binding protein (A-FABP) has been shown to be closely associated with metabolic syndrome, obesity and development of atherosclerosis. Moreover, A-FABP has been recently suggested as a potential therapeutic target of these abnormalities in animal models. The present review aims to summarize current knowledge on A-FABP functions and regulations both in animal models and humans, since the role of A-FABP in human physiology and disease has not been presently clarified.

Cell death-inducing DFF45-like effector C is reduced by caloric restriction and regulates adipocyte lipid metabolism

Members of the cell death-inducing DFF45-like effector (CIDE) gene family have been shown to regulate lipid metabolism. In this article, we report that the third member of the human CIDE family, CIDEC, is down-regulated in response to a reduced caloric intake. The down-regulation was demonstrated by microarray and real-time polymerase chain reaction analysis of subcutaneous adipose tissue in 2 independent studies on obese patients undergoing treatment with a very low calorie diet. By analysis of CIDEC expression in 65 human tissues, we conclude that human CIDEC is predominantly expressed in subcutaneous adipocytes. Together, these observations led us to investigate the effect of decreased CIDEC expression in cultured 3T3-L1 adipocytes. Small interfering RNA-mediated knockdown of CIDEC resulted in an increased basal release of nonesterified fatty acids, decreased responsiveness to adrenergic stimulation of lipolysis, and increased oxidation of endogenous fatty acids. Thus, we suggest that CIDEC is a regulator of adipocyte lipid metabolism and may be important for the adipocyte to adapt to changes in energy availability.

Moderate alcohol consumption increases insulin sensitivity and ADIPOQ expression in postmenopausal women: a randomised, crossover trial

AIMS/HYPOTHESIS

To determine whether 6 weeks of daily, moderate alcohol consumption increases expression of the gene encoding adiponectin (ADIPOQ) and plasma levels of the protein, and improves insulin sensitivity in postmenopausal women.

METHODS

In a randomised, open-label, crossover trial conducted in the Netherlands, 36 apparently healthy postmenopausal women who were habitual alcohol consumers, received 250 ml white wine ( approximately 25 g alcohol/day) or 250 ml of white grape juice (control) daily during dinner for 6 weeks. Randomisation to treatment allocation occurred according to BMI. Insulin sensitivity and ADIPOQ mRNA and plasma adiponectin levels were measured at the end of both periods. Insulin sensitivity was estimated using the homeostasis model assessment of insulin resistance (HOMA-IR). Levels of ADIPOQ mRNA in subcutaneous adipose tissue were determined by RT-PCR.

RESULTS

All subjects completed the study. Six weeks of white wine consumption reduced fasting insulin (mean +/- SEM 40.0 +/- 3.4 vs 46.5 +/- 3.4 pmol/l; p < 0.01) and HOMA-IR (1.42 +/- 0.13 vs 1.64 +/- 0.13; p = 0.02) compared with 6 weeks of grape juice consumption. ADIPOQ mRNA levels (1.09 +/- 0.15 vs 0.98 +/- 0.15; p = 0.04) and plasma levels of total (13.1 +/- 0.8 vs 12.0 +/- 0.8 microg/ml; p < 0.001) and high molecular weight (HMW) adiponectin (9.9 +/- 1.2 vs 8.8 +/- 1.2 microg/ml; p = 0.02) significantly increased after alcohol compared with juice consumption. Changes in ADIPOQ mRNA levels correlated with changes in plasma levels of total adiponectin (rho = 0.46; p < 0.01). Both fasting triacylglycerol (8.2%; p = 0.04) and LDL-cholesterol levels (7.8%; p < 0.0001) decreased, whereas HDL-cholesterol increased (7.0%; p < 0.0001) after prolonged moderate alcohol intake. No notable adverse effects were reported.

CONCLUSIONS/INTERPRETATION

Moderate alcohol consumption for 6 weeks improves insulin sensitivity, adiponectin levels and lipid profile in postmenopausal women. Furthermore, these data suggest a transcriptional mechanism leading to the alcohol-induced increase in adiponectin plasma levels.

The PPARγ ligand rosiglitazone influences triacylglycerol metabolism in non-obese males, without increasing the transcriptional activity of PPARγ in the subcutaneous adipose tissue

PPARγ is obligatory for fat mass generation and is thought to determine the amount of TAG stored per fat cell. We investigated whether ligand availability for PPARγ is rate limiting in fat mass generation and substrate metabolism. Twenty healthy men (20–29 years) were randomly assigned to receive the PPARγ ligand rosiglitazone (RSG) (8 mg/d) (n 10) or a placebo (n 10) during a stay of 7 d in a respiration chamber. Food intake was ad libitum, resulting in positive energy balances of 32·2 MJ (placebo) and 44·7 MJ (RSG). Fat cell size and expression of PPARγ, adipocyte fatty acid-binding protein (aP2), adipsin, adiponectin and fasting-induced adipose factor (FIAF) were determined in subcutaneous abdominal fat biopsies. The total amount of fat stored and the amount of TAG per fat cell were not different between groups. For the entire group, fat cell size was decreased after overeating (P = 0·02). FIAF mRNA levels were decreased after overeating in the RSG group (P = 0·01), with a trend towards a decrease in the placebo group. Unexpectedly, RSG treatment did not influence the expression levels of PPARγ and of the PPARγ responsive genes aP2, adiponectin and adipsin. In addition, RSG resulted in a larger increase in plasma TAG during overeating than placebo treatment. These results suggest that in healthy, non-obese males the PPARγ ligand RSG influences TAG metabolism, independent of its PPARγ transcriptional activity in the subcutaneous adipose tissue.