Impact of 1 25(OH) 2 D 3 on TG content in liver of rats with type 2 diabetes

Abstract Purpose: To evaluate the effects of 1,25 dihydroxy vitamin D3 (1,25(OH)2D3) on the content of triglyceride (TG), as well as on the gene and protein expressions of adiponectin receptor 2 (AdipoR2), p38 mitogen-activated protein kinase (P38MAPK), and lipoprotein lipase (LPL) in the liver of rats with type 2 diabetes mellitus (T2DM) so as to provide theoretical basis for exploring the mechanism by which 1,25(OH)2D3 regulates TG. Methods: Wistar rats were divided into four groups (n=25), with different treatments and detected the gene and protein expressions of AdipoR2, p38MAPK, and LPL in the liver tissue by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting. Meanwhile, the content of TG in the liver tissue was detected by the Enzyme-linked immunosorbent assay. Results: The expression of AdipoR2, p38MAPK, LPL gene and protein in the liver of VitD intervention group was significantly higher than that in T2DM group (P <0.05), while the TG content was significantly lower than that in T2DM group (P <0.05). Conclusion: 1,25(OH)2D3 can decrease the content of TG in the liver, and its mechanism may be achieved by upregulating the expressions of AdipoR2, p38MAPK, and LPL in the liver.

Effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture

Supplementation with conjugated linoleic acid may reduce fat body mass and increase lean body mass in various species. Some studies have demonstrated that conjugated linoleic acid reduces body fat, in part, by inhibiting the activity of lipoprotein lipase in adipocytes. The objective of this work was to study the effect of conjugated linoleic acid supplementation on lipoprotein lipase activity in 3T3-L1 adipocyte culture. 3T3-L1 adipocytes received linoleic acid (group C) or conjugated linoleic acid (group AE, supplemented with AdvantEdge® CLA, and group CO, supplemented with CLA One®) in concentrations of 1 mmol/L. Heparin-releasable lipoprotein lipase activity was analyzed by means of a 3T3-L1 adipocyte culture. After 7 days, heparin-releasable lipoprotein lipase activity was lower in the groups AE and CO supplemented with conjugated linoleic acid. These results suggest that one of the mechanisms by which CLA is capable of reducing body fat is by reducing lipoprotein lipase activity.

A suplementação com ácido linoléico conjugado pode reduzir a gordura corporal e aumentar a massa magra em diferentes espécies. Alguns estudos têm demonstrado que o ácido linoléico conjugado reduz a gordura corporal, por meio da inibição da atividade de lípase lipoprotéica em adipócitos. O objetivo deste estudo foi avaliar o efeito da suplementação com uma mistura de isômeros do ácido linoléico conjugado sobre a atividade da lípase lipoprotéica em cultura de adipócitos 3T3-L1. Os adipócitos 3T3-L1 receberam ácido linoléico (grupo controle) ou ácido linoléico conjugado (grupo AE, suplementado com AdvantEdge® CLA, e grupo CO, suplementado com CLA One®) na concentração de 1 mmol/L. A atividade de lípase lipoprotéica livre de heparina foi analisada pela média da cultura de adipócitos. Após 7 dias, a atividade da lípase lipoprotéica livre de heparina mostrou menores valores nos grupos AE e CO, suplementados com ácido linoléico conjugado. Estes resultados sugerem que um dos mecanismos pelo qual o ácido linoléico conjugado seja capaz de reduzir a gordura corporal é a partir da redução da atividade da lípase lipoprotéica.

Characterization of a fluorometric method for lipoprotein lipase

A fluorometric assay for determining lipoprotein lipase (LpL) activity is described. Dibutyrilfluorescine (DBF) was used as substrate for the enzyme and the fluorescine liberated by enzymatic hydrolysis of the substrate was measured. Extracts of acetone powder from adipose tissue as an enzyme source showed characteristics of lipoprotein lipase activity, i.e., inhibition by NaCl and optimum activity in alkaline pH. There was close agreement in LPL activity when the same sample was measured simultaneously using either dibutyrilfluorescine or tri[9, 10 3H]oleylglycerol as substrate. The extent of inhibition of lipoprotein lipase by NaCl was similar with both methods. The fluorometric method detected changes in LPL activity in heart and adipose tissue realted to the nutritional status of the animal with the same specificity and sensitivity than did the radioactive method. The flluorometric method is as sensitive, less expensive and less time consuming than the radioactive method

On the mechanism of protective action of cold acclimatization against carbon tetrachloride - and ethionine - induced fatty liver

In this study the hepatic lipoprotein lipase (LPL), activity was evaluated in adult female mice acclimatized at 5-C and submitted to carbon tetrachloride (CCI) or ethionine, in order to determine the possible role of this enzuyme in the fatty liver. The results were compared with those obtained in mice kept at room temperature (27-C) that the same hepatoesteatosis inducing agent. In contrast to animals kept at room temperature, in cold aclimatized mice neither the enhancement of the LPL-liver activity by the action of CCI or ethionine occurred nor the development of fatty infiltration in the liver was observed. We conclude that the low temperature induced a protective effect against CCI or ethionine-induced fatty liver that was correlated with the no-increase of the hepatic LPL activity