Impact of High-Sucrose Diet on the mRNA Levels for Elongases and Desaturases and Estimated Protein Activity in Rat Adipose Tissue

Abstract

Fatty acids (FAs) present in the adipose tissue (AT) can be modified by elongases and desaturases. These enzymes are regulated by different factors including nutrients. The aim of the study was to evaluate the impact of high-sucrose diet (HSD; 68% sucrose) on the levels of mRNAs for elongases (Elovl2, Elovl5, Elovl6) and desaturases (Fads1, Fads2, Scd) and on the activity of the corresponding proteins in the rat AT. Male Wistar rats were randomized into two study groups: fed with an HSD and with a standard diet (ST). The mRNA levels were determined by a semi-quantitative reverse transcription-PCR. FA composition was analyzed by gas chromatography, and FA ratios were used to estimate the activity of the enzymes. In the HSD rats, the levels of Elovl5, Elovl6, Fads1, and Scd mRNAs were higher, while the level of Fads2 mRNA was lower than in the ST group. Higher levels of Elovl5 and Elovl6 mRNAs corresponded to higher relative activities of these enzymes, while downregulation of the Fads2 mRNA was associated with the lower activity of this desaturase. In contrast, an increase in the level of Scd mRNA was accompanied by a decrease in the enzyme activity. Less monounsaturated FAs were detected in the AT of HSD rats than in the ST group. The composition of individual FAs differed between the groups. This study supports the notion that the regulation of mRNA levels and activity of both elongases and desaturases play an important role in managing the AT lipid composition in response to changes in the dietary status.

Keywords: adipose tissue; desaturases; elongases; fatty acids; high-sucrose diet.