Osteocalcin: Bone as an Endocrine Organ (2D)

Bone was long treated as a passive structural tissue, but osteoclast-mediated resorption releases the osteoblast-derived protein osteocalcin into circulation, where an acid-driven decarboxylation step activates it as a genuine hormone. This 2D diagram tracks matrix-bound osteocalcin as it is released and decarboxylated inside the acidic resorption lacuna, follows the active undercarboxylated form as it circulates to a pancreatic islet, binds GPRC6A receptors on beta cells, and drives insulin secretion — with an optional feedback arm where that insulin signals back to osteoblasts, closing a real bone-pancreas endocrine loop, plus a live strip-chart of hormone and glucose dynamics over time.