PTHrP fragments 1-16 and 1-23 do not bind to either the ETA or the ETB endothelin receptors

• Published in: Peptides (New York, N.Y. : 1980) N.Y. : 1980), 2005-08, Vol.26 (8), p.1436-1440
• Main Authors: LANGLOIS, Chantal, LETOURNEAU, Myriam, TURCOTTE, Kathy, DETHEUX, Michel, FOURNIER, Alain
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; CHO Cells; Cricetinae; Dose-Response Relationship, Drug; Endothelin-1 - metabolism; Endothelin-1 - pharmacology; Fundamental and applied biological sciences. Psychology; Guinea Pigs; Gynecology. Andrology. Obstetrics; Humans; Male; Male genital diseases; Mammary gland diseases; Medical sciences; Nephrology. Urinary tract diseases; Parathyroid Hormone-Related Protein - chemical synthesis; Parathyroid Hormone-Related Protein - metabolism; Parathyroid Hormone-Related Protein - pharmacology; Peptide Fragments - chemical synthesis; Peptide Fragments - metabolism; Peptide Fragments - pharmacology; Protein Binding; Rats; Receptor, Endothelin A - biosynthesis; Receptor, Endothelin A - metabolism; Receptor, Endothelin B - biosynthesis; Receptor, Endothelin B - metabolism; Tumors; Tumors of the urinary system; Urinary tract. Prostate gland; Vertebrates: endocrinology
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/j.peptides.2005.03.017

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.