The present study has tested the hypothesis that leptin receptors are localized in caveolae and that caveolae are involved in the leptin-induced stimulation of lipolysis in 3T3-L1 adipocytes. Leptin, a peptide hormone, is secreted primarily by adipocytes and has been postulated to regulate food intake and energy expenditure via hypothalamic-mediated effects. Exposure to leptin increases the lipolytic activity in 3T3-L1 adipocytes. We isolated caveolae from 3T3-L1 adipocytes using a detergent free sucrose gradient centrifugation method. Leptin receptors were localized in the same gradient fraction as caveolin-1. Confocal microscopic studies demonstrated the colocalization of leptin receptors with caveolin-1 in the plasma membrane, indicating distribution of leptin receptors in the caveolae. We disrupted caveolae by treating cells with methyl--cyclodextrin and found that leptin induced lipolytic activity was reduced after caveolae disruption, indicating an important role of caveolae in the signaling mechanism of leptin.
| Identifer | oai:union.ndltd.org:uky.edu/oai:uknowledge.uky.edu:gradschool_theses-1385 |
| Date | 01 January 2004 |
| Creators | Chikani, Gentle P. |
| Publisher | UKnowledge |
| Source Sets | University of Kentucky |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | University of Kentucky Master's Theses |
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