A new highly potent parathyroid hormone antagonist: [D-Trp12,Tyr34]bPTH-(7-34)NH2.
Based upon N-terminal parathyroid hormone (PTH) analog structure-activity relationship studies, position 12 was found to possess a wide structural latitude and was chosen as a site for single amino acid substitutions. Replacement of the naturally-occurring Gly with D-Trp at position 12 in the PTH antagonists [Tyr34]bPTH-(7-34)NH2 and [Nle8,18,Tyr34]bPTH-(7-34)NH2 increased in vitro receptor affinity. The D-Trp12 containing analogs were 12-fold more potent than their unsubstituted counterparts as inhibitors of PTH binding to renal and bone PTH receptors and 13-27-fold more potent as inhibitors of PTH-stimulated renal and bone adenylate cyclase activity. Based upon Scatchard analyses of saturation binding experiments and Schild analyses of adenylate cyclase experiments, [D-Trp12,Tyr34]bPTH-(7-34)NH2 was shown to interact with PTH receptors in a competitive manner. These studies demonstrate, therefore, that D-Trp12 substitution in PTH antagonists improves inhibitory properties in vitro and is compatible with a helical conformation at this position as a new direction for the design of PTH antagonists.
Goldman
M E
ME
Department of Biological Research and Molecular Biology, Merck Sharp and Dohme Research Laboratories, West Point, PA 19486.
McKee
R L
RL
Caulfield
M P
MP
Reagan
J E
JE
Levy
J J
JJ
Gay
C T
CT
DeHaven
P A
PA
Rosenblatt
M
M
Chorev
M
M
D000262:Adenylyl Cyclases / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive; D001842:Bone and Bones / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D010281:Parathyroid Hormone / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000494:pharmacology*; D010446:Peptide Fragments / Q000378:metabolism / Q000494:pharmacology*; D011956:Receptors, Cell Surface / Q000378:metabolism; D018016:Receptors, Parathyroid Hormone; D013329:Structure-Activity Relationship
D010281:Parathyroid Hormone; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; D018016:Receptors, Parathyroid Hormone; C057402:parathyroid hormone (7-34)amide,12-Trp,34-Tyr-, bovine; C025497:parathyroid hormone (3-34) amide, Nle(8,18)-Nle(34)-; D000262:Adenylyl Cyclases