Perinephric and epididymal fat affect hepatic metabolism in rats.

Abstract

The present study examined whether the perinephric and epididymal visceral fat (PEVF) depot under short-term excess nutrient protected the liver by trapping nutrient-derived nonesterified free fatty acids (NEFAs) or had deleterious effects on hepatic triglycerides (TGs) accumulation and insulin resistance due to adipokine secretion. Young rats pre-emptively underwent surgical PEVF removal or sham operations and were fed with either high-fat diet (HFD) (PEVF-HFD) or regular chow (RC) (PEVF-RC) for 3 days. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp. Liver TG, serum NEFA, and fat-derived adipokines were assessed. Insulin and lipogenesis signaling were assessed by western blots. Pre-emptive PEVF removal significantly decreases insulin-induced suppression of hepatic glucose production (HGP) both in RC and in HFD-fed rats. In accordance with the clamp results, hepatic TG accumulation is also significantly reduced by PEVF excision both in RC and HFD-fed rats. These results are further validated by insulin signaling results, which show that pre-emptive PEVF removal increases phosphorylation of hepatic Akt, irrespective of diet. Notably, high levels of serum leptin induced by HFD are significantly reduced by pre-emptive PEVF excision. Additionally, expression of lipogenic enzyme p-acetyl-CoA-carboxylase, denoting reduced lipogenesis, is increased in the PEVF-HFD rats. In conclusion, PEVF has a deleterious effect on the liver as a source of insulin resistance-inducing adipokines irrespective of diet, and does not serve as a buffer for excess nutrients.

• Authors: Shani Ben-Shlomo, Francine H Einstein, Isabel Zvibel, Dikla Atias, Amir Shlomai, Zamir Halpern, Nir Barzilai, Sigal Fishman
• Journal: Obesity (Silver Spring, Md.) (Obesity (Silver Spring)) Vol. 20 Issue 1 Pg. 151-6 (Jan 2012) ISSN: 1930-739X [Electronic] United States
• PMID: 21818154 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Fatty Acids, Nonesterified
• Triglycerides

Topics

• Analysis of Variance
• Animals
• Blotting, Western
• Diet, High-Fat (adverse effects)
• Epididymis
• Fatty Acids, Nonesterified (metabolism)
• Fatty Liver (etiology, metabolism)
• Insulin Resistance
• Intra-Abdominal Fat (metabolism)
• Kidney
• Liver (metabolism)
• Male
• Non-alcoholic Fatty Liver Disease
• Obesity (complications, metabolism)
• Phosphorylation
• Rats
• Rats, Sprague-Dawley
• Signal Transduction
• Triglycerides (metabolism)