Lipoprotein lipase (LPL) is differentially expressed in fat and heart under a variety of physiological conditions, particularly during development. LPL activity, protein and mRNA levels have been shown to rise dramatically during the first three weeks of life. The mechanism responsible for these changes in LPL in the heart during development are not fully understood. In order to address the changes in LPL in the heart during development, we measured steady state levels of LPL mRNA and the rate of LPL transcription during development. Northern blot analysis of LPL mRNA in the heart of rats from 5-120 days of age showed no changes in transcript size; however, steady state levels of LPL mRNA increased approximately 10-fold by day 20 and remained elevated thereafter. The rate of LPL transcription increased dramatically between day 5-20 and remained elevated thereafter. Thus, as opposed to other settings where posttranscriptional and posttranslational mechanisms can be important, the increased expression of LPL in rat heart that occurs during development appears to be largely due to the transcriptional activation of the gene.
Animals Blotting, Northern