Ornithine Decarboxylase Is Upregulated by the Androgen Receptor in Skeletal Muscle and Regulates Myoblast Proliferation

This study found that the Odc1 gene, which encodes ornithine decarboxylase (ODC), was directly regulated by the androgen receptor (AR) in skeletal muscle myoblasts and played a role in myoblast proliferation and differentiation. Odc1 expression was significantly reduced in muscle from male muscle-specific AR knockout mice, indicating its regulation by AR. In vitro experiments showed that Odc1 expression was higher in proliferating myoblasts compared to differentiated myotubes, and dihydrotestosterone increased Odc1 levels in myoblasts. Inhibition of ODC activity reduced myoblast numbers, while overexpression of Odc1 increased cell numbers and delayed differentiation, as evidenced by reduced expression of differentiation markers. The study concluded that androgens upregulated Odc1 via the AR, promoting myoblast proliferation and delaying differentiation.