Synthesis and characterization of a new labeled gastrin ligand, 125-I-BH-[Leu15]-gastrin-(5-17), on binding to canine fundic mucosal cells and Jurkat cells.
In the course of our study concerning gastrin and cholecystokinin (CCK) receptors, we have synthesized and characterized a new labeled gastrin ligand, 125I-BH-[Leu15]-gastrin-(5-17) [(3-[125I]iodo-4-hydroxyphenyl)-propionyl-[Leu15]-gastrin-(5-17)]. Binding of 125I-BH-[Leu15]-gastrin-(5-17) to isolated canine fundic mucosal cells was specific, saturable and of high affinity. 125I-BH-[Leu15]-gastrin- (5-17) and 125I-BH-CCK-8[(3-[125I]iodo-4-hydroxyphenyl)-propionyl-CCK-8] interact with isolated canine fundic mucosal cells with small differences in maximal binding capacities and affinities, 3800 +/- 900 binding sites/cell (Kd = 0.52 +/- 0.23 nM) and 6200 +/- 1100 binding sites/cell (Kd = 0.31 +/- 0.18 nM), respectively. The relative order of potencies for gastrin and CCK analogs in displacing 125I-BH-[Leu15]-gastrin-(5-17) binding correlated well with those obtained using 125I-BH-CCK-8. Selective CCK/gastrin antagonists L-364,718 (MK-329) and L-365,260 also inhibited 125I-BH-[Leu15]-gastrin-(5-17) binding. These results indicate that 125I-BH-[Leu15]-gastrin-(5-17) binds to gastrin receptors in isolated canine fundic mucosal cells. We have also characterized 125I-BH-[Leu15]-gastrin-(5-17) binding to the human Jurkat lymphoblastic cell line (Jurkat cells) known to express the CCK-B/gastrin receptor. Saturation experiments have shown that both 125I-BH-[Leu15]-gastrin-(5-17) and 125I-BH-CCK-8 interact with a single class of high-affinity binding sites in the Jurkat cell line.(ABSTRACT TRUNCATED AT 250 WORDS)
Galleyrand
J C
JC
Laboratory of the Chemistry and Pharmacology of Molecules of Biological Interest, URA CNRS 1845, Faculty of Pharmacy, Montpellier, France.
Lima-Leite
A C
AC
Lallement
J C
JC
Lignon
M F
MF
Bernad
N
N
Fulcrand
P
P
Martinez
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002766:Cholecystokinin / Q000037:antagonists & inhibitors; D020109:Devazepide; D004285:Dogs; D005748:Gastric Fundus / Q000378:metabolism; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism*; D005755:Gastrins / Q000138:chemical synthesis* / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007457:Iodine Radioisotopes; D007700:Kinetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis* / Q000378:metabolism* / Q000494:pharmacology; D010671:Phenylurea Compounds; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors; D012844:Sincalide / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D013696:Temperature
C089482:3-(3-iodo-4-hydroxyphenyl)propionyl(Leu(15))gastrin-(5-17); D001570:Benzodiazepinones; D005755:Gastrins; D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D010671:Phenylurea Compounds; D011949:Receptors, Cholecystokinin; C058121:L 365260; D002766:Cholecystokinin; D020109:Devazepide; D012844:Sincalide; D002118:Calcium