title: Differential expression of calcitonin and parathyroid hormone/parathyroid hormone-related protein receptors in P19 embryonic carcinoma cells treated with retinoic acid.
abstract: Mouse embryonic carcinoma P19 cell aggregates treated with retinoic acid (RA) sequentially differentiate into neurons and astrocytes, whereas attached cells develop a mesodermal phenotype. The expression of calcitonin (CT) and PTH/PTH-related protein (PTHrP) receptors was investigated in embryonic cells, and during neural and mesodermal differentiation. In embryonic P19 cells, specific binding of [125I]salmon (s) CT(1-32) ([125I]sCT(1-32)) was 56 fmol/mg protein, and of [125I]chicken (ch) [Tyr36]PTHrP(1-36) amide ([125I]chPTHrP(1-36)) < 0.5 fmol/mg protein. Correspondingly, cAMP was maximally stimulated 47-fold by sCT(1-32) (EC50 0.05 nM) and 3-fold by chPTHrP(1-36) (EC50 1.3 nM). Receptor autoradiography revealed specific binding of [125I]sCT(1-32) to the undifferentiated P19 cells, but not to RA induced neurons and astrocytes. At the same time, [125I]sCT(1-32) binding and cAMP accumulation by sCT were gradually decreased. But, specific binding of [125I]chPTHrP(1-36) was raised at least 6-fold compared with embryonic cells to 3 fmol/mg protein, in parallel with a 10-fold higher maximal cAMP accumulation. A similar, but delayed suppression of CT and stimulation of PTH/PTHrP receptor expression was observed during mesodermal cell differentiation. The results indicate that CT receptors are associated with undifferentiated P19 cells, whereas PTH/PTHrP receptors are expressed in RA induced neural and mesodermal cells.
authors.affiliation: Department of Orthopedic Surgery, University of Zurich, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Eggenberger
authors.forename: R A
authors.initials: RA
authors.lastname: McKinney
authors.forename: J A
authors.initials: JA
authors.lastname: Fischer
authors.forename: R
authors.initials: R
authors.lastname: Muff
mesh_terms: D000818:Animals; D001345:Autoradiography; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D008648:Mesoderm / Q000737:chemistry; D051379:Mice; D014411:Neoplastic Stem Cells / Q000737:chemistry* / Q000187:drug effects; D044168:Receptor, Parathyroid Hormone, Type 1; D018003:Receptors, Calcitonin / Q000032:analysis*; D018016:Receptors, Parathyroid Hormone / Q000032:analysis*; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D044168:Receptor, Parathyroid Hormone, Type 1; D018003:Receptors, Calcitonin; D018016:Receptors, Parathyroid Hormone; D014212:Tretinoin