FIGURE 7.

Exogenous expression of Insig-2a in primary cultures of rat hepatocytes inhibits SREBP-1c processing by insulin. A, hepatocytes co-infected with Ad-HisSREBP-1cFLAG and Ad-Insig2aFLAG or Ad-LacZ were incubated in medium containing insulin (100 nm) or without additions for 24 h. ALLN (25 μg/ml) was added during the final 6 h of incubation, and cells were harvested. Nuclear extracts were fractionated by SDS-PAGE, and immunoblots were developed using anti-His or anti-histone antibodies. Microsomal fraction was immunoblotted with anti-FLAG antibodies to assess the expression of Insig-2a (bottom panel). B, densitometric quantification of nSREBP-1c bands from three independent blots as shown in A; the data are expressed as a percentage of control optical density of the nSREBP-1c-specific band. *, p < 0.05 versus control; **, p < 0.05 versus insulin treatment.