[Function of the PTH/PTHrP receptor].

Cloning of the PTH/PTHrP receptor has established a new class of a receptor family which couples with G-proteins. When this receptor is occupied by PTH or PTHrP, activation of adenylate cyclase and phospholipase C occurs. Site-specific mutagenesis is extensively employed to study the structure-function relationship. The mechanisms whereby PTH/PTHrP receptor level is regulated are also being studied. PTH/PTHrP receptor knock-out and PTHrP knock-out mice show similar skeletal abnormalities but the former apparently die earlier before birth. There are still many problems to be elucidated, such as the reason for the subtle difference of PTH action and PTHrP action, and the role that this receptor plays in the pathogenesis of pseudohypoparathyroidism Ib.