Growth hormone regulates the expression of UCP2 in myocytes

• Signaling pathways activated by growth hormone (GH) during energy metabolism analyzed.
• GH found to directly enhance expression of UCP2, key protein in energy metabolism.
• Effect mediated via STAT5B, signal transducer downstream of GH.
• Results may aid development of drugs for treatment of AGHD and obesity.

ObjectiveTo determine if and how growth hormone (GH) signaling is involved in energy metabolism.DesignWe used human embryonic kidney TSA201 cells, human H-EMC-SS chondrosarcoma cells, rat L6 skeletal muscle cells, and murine C2C12 skeletal muscle myoblasts to investigate GH-induced expression of uncoupling protein2 (UCP2) to the GHR/JAK/STAT5 pathway by a combination of a reporter assay, electrophoretic mobility shift assay (EMSA), real-time quantitative PCR, Western blotting.ResultsWe demonstrated that the regulation energy metabolism, which was hypothesized to be directly acted on by GH, involves UCP2 via activated STAT5B, a signal transducer downstream of GH. We also showed that the sequence at the − 586 ‘TTCnGA’ may function as a novel putative consensus sequence of STAT5s.ConclusionThe results suggest that GH regulates energy metabolism directly in myocytes and that UCP2 participates in the signal transduction pathway that functions downstream of the GHR/JAK/STAT.