Figure 6.

Amounts of mRNA for the LDL receptor, HMG CoA synthase, and HMG CoA reductase in livers of female Syrian hamsters fed the indicated diet for 12 days. Total RNA was isolated from livers of the same hamsters shown in Table 1 and Figs. 2 and 3. Aliquots of total RNA (10 μg) from pooled samples of five livers were hybridized in solution for 10 min at 68°C to ³²P-labeled cRNA probes for the LDL receptor, HMG CoA synthase, and HMG CoA reductase, all in the presence of a cRNA probe for β-actin as described in Methods. After RNase digestion, the protected fragments were separated by gel electrophoresis and exposed to film at −80°C with an intensifying screen for 16 hr for LDL receptor and for 8 hr for HMG CoA synthase and reductase. The radioactivity in the gels was quantified by PhosphorImaging, normalized to the β-actin signal, and expressed relative to the mRNA level of control chow-fed hamsters. L/C, lovastatin/Colestipol; LDLR, LDL receptor.