Ipriflavone-specific receptor

The Ipriflavone-specific receptor is a putative cell surface receptor primarily expressed on osteoclast precursor cells and mature osteoclasts. It was first characterized as a novel binding site for ipriflavone, a synthetic isoflavone derivative used to manage metabolic bone diseases such as osteoporosis. Activation of this receptor by ipriflavone triggers a rapid and sustained increase in cytosolic free calcium levels through dihydropyridine-insensitive calcium channels. This signaling pathway leads to the inhibition of osteoclast differentiation, specifically the fusion of precursors into multinucleated cells, and a reduction in the bone-resorbing activity of mature osteoclasts. Binding studies have identified two classes of specific binding sites on both precursor and mature cells, with dissociation constants in the nanomolar and micromolar ranges. Notably, this receptor is distinct from estrogen receptors and other known calcium-regulating hormone receptors, such as those for parathyroid hormone or calcitonin. While ipriflavone has been used clinically to maintain bone mass, its therapeutic application is limited by safety concerns, most notably lymphocytopenia, and its potential to inhibit certain cytochrome P450 enzymes.

Other names

Ipriflavone receptorIP receptorNovel ipriflavone receptorIpriflavone binding site

Activation of the receptor induces an influx of extracellular calcium through dihydropyridine-insensitive calcium channels, which inhibits the differentiation of osteoclast precursors and the bone-resorbing activity of mature osteoclasts.