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Regulation of Hepatic Stearoyl-CoA Desaturase Gene 1 by Vitamin A

https://doi.org/10.1006/bbrc.1997.6070Get rights and content

Abstract

The effect of vitamin A supplementation on stearoyl-CoA desaturase gene 1 expression in mouse liver was characterized. Normal BALB/c mice were fed 0.01% and 0.1% retinol palmitate as components of nonpurified diets. This treatment resulted in a 3-fold and a 7-fold induction of SCD1 mRNA levels, respectively, as determined by RNase protection analysis. Vitamin A-deficient animals were also fed diets containing 0.01% and 0.1% retinol palmitate, resulting in a similar pattern of SCD1 mRNA induction. Fatty acid synthase and β-actin mRNA levels did not respond consistently or significantly to retinoic acid treatment. Dietary and hormonal studies were carried out to investigate the role of the retinoid X receptor in the regulation of SCD1 by type II steroid hormones. A receptor-saturating dose of thyroid hormone, triiodothyronine, repressed vitamin A-elevated SCD1 mRNA levels in vivo. Peroxisome proliferator-elevated SCD1 mRNA levels were unaffected by administration of thyroid hormone. This suggests that the retinoic acid receptor transcriptionally regulates SCD1 through a traditional mechanism of heterodimerization with the retinoid X receptor.

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Abbreviations used: FAS, fatty acid synthasePPAR, peroxisome proliferator-activated receptor; RAR, retinoic acid receptor; RXR, retinoid X receptor; SCD, stearoyl-CoA desaturase; T3R, thyroid hormone receptor;

1

To whom correspondence should be addressed at Department of Biochemistry, The University of Wisconsin–Madison, 420 Henry Mall, Madison, WI 53706. Fax: (608) 265-3272.

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