P12 - PTHC1: A Continuing Cell Line Expressing PTH and Genes Involved in Calcium Homeostasis

The main organs regulating serum levels of ionised calcium (Ca2+) are the parathyroids, which are composed of two different cell types: chief cells and oxyphil cells. Chief cells, through the calcium sensing receptor (CaSR), are affected by changes in calcium concentration, modifying PTH secretion in proportion to calcium levels. Current understanding of calcium regulation mechanisms connected to PTH and of the signalling pathways involved derive from in vitro studies carried out on primary cultures of scattered parathyroid cells, because there do not exist parathyroid cell lines able to excrete calcium-regulated PTH. Indeed, it is very difficult to obtain continuous parathyroid cell lines that conserve their functional characteristics because these cells, once cultured, quickly lose their response to calcium. PT-r cells, obtained in 1995 by subsequent clonings, constitute, to date, the only continuous parathyroid cell line described in the literature. This study describes a new cell clone able to secrete PTH, called PTHc1, obtained from hyperplastic tissue of the parathyroid rat.