Gastrin receptors in normal and malignant gastrointestinal mucosa: age-associated changes.

Pomila Singh, B. Rae-Venter, Courtney Townsend, T. Khalil, J. C. Thompson

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Abstract

Synthetic human gastrin 17-I (MG) and an analogue, [Leu15]gastrin-17-I (LG), were radiolabeled with Na125I by Iodo-Gen, EnzymoBead, and chloramine-T methods, and the characteristics of the radiolabeled peptides were determined. When 125I-MG was iodinated by chloramine-T, its biological activity and its binding activity were almost abolished, whereas the biological activity of 125I-LG, iodinated by either of the methods, and of 125I-MG, iodinated by Iodo-Gen and EnzymoBeads, was not significantly affected. The kinetics, affinity, and specificity of binding of 125I-MG, iodinated by Iodo-Gen, to crude and purified membranes from rat fundic mucosa were examined and found to be similar to that for 125I-LG. Age-associated changes in the number and affinity of gastrin receptors (GR) on the crude membranes of gastrointestinal mucosa of rats was also examined. Significantly fewer GR were observed on the crude membranes of fundic mucosa of aged (24 mo old) compared with young (3- and 6-mo-old) rats. In addition, specific gastrin-binding sites (4.7 +/- 0.9 fmol/mg prot) with low affinity (Kd = 3.7 +/- 1.2 nM) were observed in the antrum of aged rats, the significance of which is not understood. There were, however, no differences in the number and characteristics of GR in other regions of the intestine of old and young rats. The presence of GR was additionally assessed in cell lines of gastrointestinal cancers from humans, mice, and hamsters.(ABSTRACT TRUNCATED AT 250 WORDS)

Original languageEnglish (US)
JournalThe American journal of physiology
Volume249
Issue number6 Pt 1
StatePublished - Dec 1985

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Cholecystokinin B Receptor
Mucous Membrane
Membranes
Gastrointestinal Neoplasms
Gastrins
Cricetinae
Intestines
Binding Sites
Cell Line
Peptides
1,3,4,6-tetrachloro-3 alpha,6 alpha-diphenylglycoluril

ASJC Scopus subject areas

  • Medicine(all)

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Gastrin receptors in normal and malignant gastrointestinal mucosa : age-associated changes. / Singh, Pomila; Rae-Venter, B.; Townsend, Courtney; Khalil, T.; Thompson, J. C.

In: The American journal of physiology, Vol. 249, No. 6 Pt 1, 12.1985.

Research output: Contribution to journalArticle

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