CONICET | Buscador de Institutos y Recursos Humanos

We have previously demonstrated that vitamin A deficiency alters liver phospholipid metabolism by decreasing its synthesis and content. This fact was associated to a reduced Fatty Acid Synthetase activity (FAS). Since this enzyme participates in the fatty acid synthesis, in the present study we examine the triglyceride content and mRNA expression of the regulatory enzymes involved in its synthesis in the liver of vitamin A deficient rats. Female Wistar rats at 21 days old were randomly weaned onto either a vitamin A deficient diet (-A group) or the same diet added with vitamin A 4000 IU/kg diet (control group) and fed for three months before sacrifice. Vitamin A deficiency was confirmed by retinol levels in plasma (0.55 ± 0.01 vs 1.89 ± 0.01 umol/L, p< 0.005) and liver (0.06 ± 0.002 vs 1.80 ± 0.11 umol/g, p>0.001) using HPLC. Liver lipids were extracted with hexane / isopropanol mixture (3:2, by vol), containing butylated hydroxytoluene as antioxidant. The TG were quantified after separation by TLC plates coated with silica gel G using hexane /diethyl ether /acetic acid (80:20:1, by vol) as solvent. The mRNA levels of hepatic Diacylglycerol acyltransferases (DAGAT 1 and 2) were measured by Reverse Transcription-Polymerase Chain Reaction (RT-PCR). The bands were quantified using the software program Scion Image from NIH and normalized by the values obtained for b-actin. The statistical analysis was performed using Student´s t test. The vitamin A deficiency did not affect the triglycerides content in relation to control (0.77 ± 0.01 vs 0.73 ± 0.02 µmol/g liver). The mRNA levels of DAGAT-1 was increased (p< 0.01), while DAGAT-2 did not, in the liver of vitamin A deficient rats, compared with control. These results suggest that the regulation of liver triglycerides synthesis in the vitamin A deficient rats could depend of enzymes or factors other than mRNA DAGAT and FAS, which could be regulated by retinoic acid.

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