Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01350 (gastrin)
 9,683 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of dopamine (DA) on acid secretion was studied using the everted preparation of isolated rat stomachs. DA concentrations, measured by HPLC-ECD in the rumen, corpus and antrum were 1.06 nmol/mg protein, 0.49 nmol/mg protein and 2.92 nmol/mg protein, respectively. DA stimulated acid secretion at a concentration of 10 nM and elicited the maximum response at 10 microM, which was at a level approximately 1.56-fold that of the spontaneous secretion but only about half that of secretion induced by histamine at a concentration of 0.3 mM. The concentration-dependent stimulation by DA was antagonized by octopamine and SCH 23390. Failure of proglumide and cimetidine to affect this stimulation ruled out the participation of histamine and/or gastrin. Scopolamine and tetrodotoxin completely inhibited the acid secretion induced by low concentrations of DA but inhibited only partially the response induced by high concentrations of DA. The results obtained indicate that DA induces acid secretion via activation of the dopamine D1 receptor, located on the cholinergic neurons and on some nonneuronal cells, in the rat stomach.
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PMID:Stimulatory effect of dopamine on acid secretion from the isolated rat stomach. 775 4

Gastrin-17 (G17) processing intermediates bind to non-CCK receptors which mediate growth of the colonic mucosa but also the formation and development of colonic cancers. In previous studies, we removed the C-terminal region of G17 to form G17(1-12) and considerably shorter C-terminally amidated and non-amidated analogs. Peptides as short as G17(1-4) continued to bind to a single site on DLD-1 human colonic carcinoma cells, while only the G17(1-6)-NH(2) and G17(1-12) peptides retained the ability to activate the receptor and stimulate cell proliferation in vitro. In this report, we studied the structure of these analogs, using a combination of ECD and VCD spectroscopy and replica exchange molecular dynamics (REMD) simulations in water, TFE, and membrane-mimicking environments, in order to determine preferred conformations that may have importance in promoting the biological activities. Mostly random meander structures, punctuated by a beta-turn at residues 1-4, were found in most peptides by REMD simulations. G17(1-3)-NH(2), which cannot form a beta-turn, failed to bind the non-CCK receptor, suggesting the importance of this feature for binding. Additionally, the beta-turn appeared more frequently in longer sequences, possibly explaining the higher affinity of the non-CCK receptor for these peptides seen previously. Finally, C-terminally amidated peptides generally showed greater formation of turn structure than their non-amidated counterparts as shown by ECD spectra, suggesting the importance of peptide length in stabilizing turn structure in N-terminal sequences, and perhaps explaining the ability of G17(1-6)-NH(2) to activate the non-CCK receptor where as the non-amidated G17(1-6) and shorter peptides do not.
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PMID:The structure of bioactive analogs of the N-terminal region of gastrin-17. 1976 82