PTHrP plays a major role in regulating calcium homeostasis in vertebrates, including sea bream, chick, and mammals.

[5] In 2005, Australian pathologist and researcher Thomas John Martin found that PTHrP produced by osteoblasts is a physiological regulator of bone formation.

By these findings, they demonstrated that PTHrP plays a central role in physiological regulation of bone formation by promoting recruitment and survival of osteoblasts.

[6] PTHrP is critical in intraosseous phase of tooth eruption where it acts as a signalling molecule to stimulate local bone resorption.

In the context of tooth eruption, PTHrP is secreted by the cells of the reduced enamel epithelium.

[13] However, PTHrP has a less sustained action than PTH on PTHR1 activation, which may explain at least in part its reduced ability to stimulate 1,25-dihydroxyvitamin D (1,25(OH)2 vitamin D) production and indirectly intestinal calcium absorption through an action to increase circulating levels of 1,25(OH)2 vitamin D.[14] PTHrP is found in the proliferative zone of the growth plate.

[22] This article incorporates text from the United States National Library of Medicine, which is in the public domain.