PTHrP fragments 1-16 and 1-23 do not bind to either the ETA or the ETB endothelin receptors.
Because of some isofunctional similarities with endothelin-1 (ET-1), it has been suggested that PTHrP(1-16) and PTHrP(1-23) could interact with osteoblast cells via ETA receptors. To document this interaction, we used the thoracic rat aorta and the guinea-pig lung parenchyma paradigms as ETA and ETB models, respectively. In addition, we also performed a series of competition experiments against [125I]ET-1, using transfected cells expressing the ETA or ETB receptor. So far, no agonistic nor antagonistic activities were observed in the ETA and ETB bioassays with the PTHrP fragments. Furthermore, both fragments were unable to displace [125I]ET-1 bound to cells expressing the ETA or ETB receptor.
Langlois
Chantal
C
Institut National de la Recherche Scientifique - Institut Armand-Frappier, Université du Québec, 245 boul. Hymus, Pointe-Claire (Montréal), QC, Canada H9R 1G6.
Létourneau
Myriam
M
Turcotte
Kathy
K
Detheux
Michel
M
Fournier
Alain
A
D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000378:metabolism / Q000494:pharmacology; D006168:Guinea Pigs; D006801:Humans; D008297:Male; D044162:Parathyroid Hormone-Related Protein / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding; D051381:Rats; D044022:Receptor, Endothelin A / Q000096:biosynthesis / Q000378:metabolism*; D044023:Receptor, Endothelin B / Q000096:biosynthesis / Q000378:metabolism*
D019332:Endothelin-1; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; C085849:parathyroid hormone-related protein (1-16); C506336:parathyroid hormone-related protein (1-23)