ESTROGEN REGULATION OF ADIPOSE-TISSUE LIPOPROTEIN-LIPASE - POSSIBLE MECHANISM OF BODY-FAT DISTRIBUTION

OBJECTIVE: The purpose of this study was to evaluate the regulation of lipoprotein lipase activity, protein mass, and messenger ribonucleic acid by estradiol. STUDY DESIGN: Premenopausal women not taking exogen ous sex steroids had transdermal 17 beta-estradiol and placebo patches placed in the gluteal region during the early follicular phase of the menstrual cycle. Adipose biopsies were performed from beneath the pat ches. Adipose tissue lipoprotein lipase activity was determined by a r adiometric assay, protein mass was determined by enzyme-linked immunos orbent assay, and messenger ribonucleic acid level was determined by N orthern analysis. Comparisons between the treated and placebo sides we re analyzed by nonparametric statistics. RESULTS: Adipose tissue from beneath the 17 beta-estradiol patch had significantly decreased lipopr otein lipase activity and extracellular protein mass than did adipose tissue from beneath the placebo patch. There was no difference in lipo protein lipase messenger ribonucleic acid levels. CONCLUSION: Estrogen decreases lipoprotein lipase activity by a posttranscriptional modifi cation of protein levels. A hypothesis of sex steroid regulation of bo dy fat distribution is proposed.