Binding of a iodinated substance P analog to a NK-1 receptor on isolated cell membranes from rat anterior pituitary.
The characteristics of binding sites for substance-P (SP) on rat anterior pituitary membranes were studied, using 125I-labeled Bolton-Hunter SP as a ligand. The binding of [125I]Bolton-Hunter SP was saturable and reversible, and reached a plateau of maximal binding after approximately 12 min of incubation. Scatchard and Hill analyses of specific binding revealed a single class of noninteracting binding sites with a high affinity (Kd = 0.72 nM) and a moderate density (binding capacity = 32.16 fmol/mg protein). The biologically active tachykinins, which, in addition to SP, consist of physalaemin, eledoisin, kassinin, neurokinin-A, and neurokinin-B, could inhibit the binding in a concentration-dependent manner. Based on titration curves, the IC50 values of the tachykinins were measured, and the receptor was classified as a NK-1 receptor. These results demonstrate that a population of specific SP-binding sites is present in rat anterior pituitary and further support evidence that this peptide has an influence on pituitary function.
Larsen
P J
PJ
Institute of Medical Anatomy B, University of Copenhagen, Denmark.
Mikkelsen
J D
JD
Saermark
T
T
D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism; D008297:Male; D010903:Pituitary Gland, Anterior / Q000378:metabolism* / Q000648:ultrastructure; D011094:Polyethyleneimine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D017981:Receptors, Neurotransmitter / Q000145:classification / Q000378:metabolism*; D018039:Receptors, Tachykinin; D013373:Substance P / Q000031:analogs & derivatives / Q000378:metabolism*; D013388:Succinimides / Q000378:metabolism*
C043194:Bolton Hunter reagent-substance P conjugate; D017981:Receptors, Neurotransmitter; D018039:Receptors, Tachykinin; D013388:Succinimides; D013373:Substance P; D011094:Polyethyleneimine