TRANSCRIPTIONAL REGULATION OF LIPOPROTEIN-LIPASE IN THE HEART DURING DEVELOPMENT IN THE RAT

Lipoprotein lipase (LPL) is differentially expressed in fat and heart under a variety of physiological conditions, particularly during devel opment. LPL activity, protein and mRNA levels have been shown to rise dramatically during the first three weeks of life. The mechanism respo nsible for these changes in LPL in the heart during development are no t fully understood. In order to address the changes in LPL in the hear t during development, we measured steady state levels of LPL mRNA and the rate of LPL transcription during development. Northern blot analys is of LPL mRNA in the heart of rats from 5-120 days of age showed no c hanges in transcript size; however, steady state levels of LPL mRNA in creased similar to 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 impo rtant, the increased expression of LPL in rat heart that occurs during development appears to be largely due to the transcriptional activati on of the gene. (C) 1994 Academic Press, Inc.