BGLAP Protein, Rat (GST)

BGLAP protein, in its carboxylated form, plays a crucial role in the bone matrix by acting as a negative regulator of bone formation while maintaining bone resorption and mineralization. This form exhibits strong binding affinity to apatite and calcium. On the other hand, the uncarboxylated form functions as a hormone secreted by osteoblasts and regulates various cellular processes including energy metabolism, male fertility, and brain development. In terms of energy metabolism, it promotes pancreatic beta-cell proliferation, insulin secretion, insulin sensitivity, and energy expenditure. Additionally, the uncarboxylated osteocalcin hormone stimulates testosterone production in the testes by acting as a ligand for G protein-coupled receptor GPRC6A on Leydig cells, resulting in the activation of CREB-dependent pathways required for testosterone synthesis. Furthermore, this hormone serves as a regulator of brain development by crossing the blood-brain barrier and binding to GPR158 on neurons. This interaction prevents neuronal apoptosis in the hippocampus, promotes the synthesis of monoamine neurotransmitters, and inhibits the synthesis of gamma-aminobutyric acid (GABA). Notably, osteocalcin also crosses the placenta during pregnancy, and maternal osteocalcin is necessary for fetal brain development.