Effect of Non-Esterified Fatty Acids on Fatty Acid Metabolism-Related Genes in Calf Hepatocytes Culturedin Vitro

Abstract

Background: NEFA plays numerous roles in the metabolism of glucose, lipids, and proteins. A number of experimental studies have shown that NEFA may have an important role in fatty acid metabolism in the liver, especially in dairy cows that experience negative energy balance (NEB) during early lactation. Methods: In this study, using fluorescent quantitative RT-PCR, ELISA, and primary hepatocytes cultured in vitro, we examined the effect of NEFA (0, 0.2, 0.4, 0.8, 1.6, and 3.2 mmol/L) on fatty acid metabolism by monitoring the mRNA and protein expression of the following key enzymes: long chain acyl-CoA synthetase (ACSL), carnitine palmitoyltransferase IA (CPT IA), long chain acyl-CoA dehydrogenase (ACADL), and acetyl-CoA carboxylase (ACC). Results: The mRNA and protein expression levels of ACSL and ACADL markedly increased as the concentration of NEFA in the media was increased. The mRNA and protein expression levels of CPT IA were enhanced significantly when the NEFA concentrations increased from 0 to 1.6 mmol/L and decreased significantly when the NEFA concentrations increased from 1.6 to 3.2 mmol/L. The mRNA and protein expression of ACC decreased gradually with increasing concentrations of NEFA. Conclusion: These findings indicate that increased NEFA significantly promote the activation and β-oxidation of fatty acids, but very high NEFA concentrations may inhibit the translocation of fatty acids into mitochondria of hepatocytes. This may explain the development of ketosis or liver lipidosis in dairy cows. CPT IA might be the key control enzyme of the fatty acid oxidation process in hepatocytes.

Up-Regulation Mttp and Apob Gene Expression in Rat Liver is Related to Post-Lipectomy Hypertriglyceridemia

“…Liver biosynthesis of TAGs is enhanced due to increased availability of fatty acids synthesized from glucose in hepatocytes [47]. Also the assembly of VLDL and resultant production of TAGs are known to be fatty acid-dependent [22].…”

Treatment and post-treatment effects of dietary supplementation with safflower oil and linseed oil on milk components and blood metabolites of Canadian Holstein cows

“…Dietary unsaturated fatty acids (UFA) may modulate the metabolism of dairy cows and hence influence the levels of some blood metabolites like glucose, non-esterified fatty acid (NEFA), triacylglyceride (TAG), beta-hydroxybutyric acid (BHBA) and milk components like fat, protein, urea nitrogen and lactose. Non-esterified fatty acids are one of the most important metabolites in the blood of dairy cows, especially in the transition period (3 weeks before and 3 weeks after parturition) (Li et al 2013). Elevated concentrations of NEFA and BHBA have been used as indicators of excessive negative energy balance associated with increasing risk of diseases during the transition period in dairy cows (LeBlanc et al 2005;Chapinal et al 2011).…”

β-Hydroxybutyrate Facilitates Fatty Acids Synthesis Mediated by Sterol Regulatory Element-Binding Protein1 in Bovine Mammary Epithelial Cells

“…Importantly, perinatal dairy cows usually experience a period of negative energy balance (NEB) induced by decreased dry matter intake and increased energy demand. Excessive NEB leads to lipid mobilization then results in high blood concentrations of non-esterified fatty acids (NEFAs) [3]. Ketone bodies are generated when large amount of NEFAs are beyond the oxidative ability of liver [4].…”