A MODEL CELL-LINE TO STUDY REGULATION OF STEAROYL-COA DESATURASE GENE-1 EXPRESSION BY INSULIN AND POLYUNSATURATED FATTY-ACIDS

Insulin and polyunsaturated fatty acids (PUFAs) regulate the expressio n of SCD1 gene in mouse liver. Accordingly, we examined the insulin an d PUFA regulation of SCD1 gene expression in H2.35 cells. The levels o f SCD1 mRNA in H2.35 cells increased at the restrictive temperature of 39 degrees C, when the glucose-containing medium was supplemented wit h insulin. The insulin-stimulated expression of SCD1 mRNA was signific antly blunted when the induction medium was supplemented with linoleni c acid (18:2n-3 and arachidonic acid (20:4n-6). Stearic acid(18:0n-9) and oleic acid(18:1n-9) were without dramatic effects. The effect of i nsulin and PUFAs on a transfected SCD1 fusion gene (SCD1.CAT4.3) was a lso examined in H2.35 cells. Whereas insulin stimulated SCD1.CAT4.3 ex pression, arachidonic acid significantly decreased SCD1 CAT4.3 activit y. These studies suggest that insulin and PUFAs regulate SCD1 gene tra nscription via regulatory DNA sequences flanking the 5' end of the gen e. (C) 1996 Academic Press, Inc.