| Title | Thyroid-stimulating hormone stimulates lipolysis in adipocytes in culture and raises serum free fatty acid levels in vivo. | | Author(s) | Gagnon A, Antunes TT, Ly T, Pongsuwan P, Gavin C, Lochnan HA, Sorisky A | | Institution | Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada K1H 8L6; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada K1H 8M5. | | Source | Metabolism 2009 Oct 19. | | Abstract | Thyroid-stimulating hormone (TSH) stimulates adipocyte lipolysis, but signal transduction pathways activated by TSH for this response have not been directly studied. Using differentiated 3T3-L1 adipocytes as well as primary human adipocytes, we characterized the lipolytic action of TSH with dose-response and time-course studies, and compared it with isoproterenol. Thyroid-stimulating hormone stimulated phosphorylation of perilipin and hormone-sensitive lipase (HSL). Inhibition of protein kinase A with H89 blocked TSH-stimulated lipolysis as well as phosphorylation of perilipin and HSL. Thyroid-stimulating hormone stimulated lipolysis in vivo, as indicated by an elevation in serum free fatty acid (FFA) levels after recombinant human TSH administration to thyroidectomized patients (42% increase, n = 19, P < .05). For patients with a body mass index less than 30 kg/m(2), the TSH-induced increase in serum FFA levels was 53% (n = 11, P < .05), whereas levels in patients with a body mass index of at least 30 kg/m(2) (n = 8) did not change after TSH treatment. In summary, TSH stimulates lipolysis and phosphorylation of perilipin and HSL in a protein kinase A-dependent manner in differentiated adipocytes in culture and raises serum FFA levels in vivo. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19846175 |
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