Figure 2

Expression profiles of fatty acid and cholesterol biosynthetic pathway genes following exposure of murine myoblasts to IGF-1. The expression values (derived from microarray studies) are plotted as relative change over untreated control (100) values for Fatty acid synthase (Fas), ATP citrate lyase (Acly), Acyl CoA synthetase (Acs) (Fig. 2 A; Fatty acid desaturase (Fads), sterol C5 desaturase (SC5d), and Stearoyl CoA desaturase 1 (Scd1) (Fig. 2B). Data shows a two-fold or greater induction with IGF-1 treatment for all these genes (Fig. 2 A-B). Relative gene expression profiles are also shown for the genes involved in cholesterol biosynthesis (Fig 2C–F), namely HMG CoA synthase 1 (Hmgcs1) and HMG CoA reductase (Hmgcr) (Fig. 2C); Mevalonate (diphospho) decarboxylase (Mvd), Mevalonate kinase (Mk) and Phosphomevalonate kinase (Pmk) (Fig. 2D). Profiles are also shown for Cyp51, Hydroxysteroid dehydrogenase 17 beta (Hsd17b7), Lanosterol synthase (Lss) (Fig. 2E) and for the Low density Lipoprotein receptor (Ldlr), START domain 4 (Startd4) and cholesterol 25-hydroxylase (M25oh) genes (Fig. 2F). The genes involved in fatty acid and cholesterol biosynthesis are coordinately induced by IGF-1, though subtle variations exist in the time and extent of induction. In general, the induction is about 3–4 fold.