Frequency and sequence complexity of liver poly(A)+ mRNAs from rats fed fat-free or high fat diets.

We demonstrate by messenger RNA (mRNA) . complementary DNA (cDNA) hybridization that nutrient variation can alter 1) the frequency in which entire classes or families of liver polyadenylated mRNAs [poly(A)+ mRNAs] are present within the cell and 2) the sequence complexity of those transcripts. Feeding a carbohydrate-rich, fat-free diet to rats for 5 days resulted in an increased sequence complexity of rare and moderately abundant liver poly(A)+ mRNAs when compared with poly(A)+ mRNA from rats fed high fat or basal diets. In addition, the frequency of reiteration of abundant sequences increased approximately 10 times compared with the abundant poly(A)+ mRNAs of rats fed high fat or basal diet. The results indicate that the functionality of the template is influenced by nutrient concentrations and may be one means by which complex organisms achieve homeostasis.