Identification and measurement of molecular variants of cholecystokinin in duodenal mucosa and plasma. Diminished concentrations in patients with celiac disease.

Abstract

A B S T R A C T The amount and type of cholecystokinin (CCK) in duodenal extracts and plasma of celiac patients and normal subjects was studied by radioimmunoassay and gel filtration. In both groups there were similar patterns of molecular forms in extracts of duodenal biopsies, but concentrations in celiac disease were significantly depressed. In boiling water extracts of duodenal mucosa from both groups a factor with the properties of the COOH-terminal octapeptide of cholecystokinin predominated, but there were also significant amounts of a larger molecular weight form. In acid extracts of mucosa a factor with the properties of the 33 or 39 residue form was identified in amounts that were -25% those of CCK8; there were also similar amounts of an acid-soluble form that had an apparent molecular weight higher than CCK39. Plasma immunoreactive cholecystokinin was studied after concentration by immunoaffinity adsorption and fractionation by gel filtration. In normal subjects fasting CCK-like immunoreactivity was <0.8 pmol/liter, and after a light breakfast increased to 2.0±0.7(range 1.0 to 4.8) pmol/liter; CCK8-like activity accounted for all the increased immunoreactivity. In five of six celiac patients the concentrations of both fasting and postprandial CCK-like immunoreactivity in plasma were undetectable (<0.8 pmol/liter). We conclude that diminished production and release of CCK could account for the impaired pancreatic and gall bladder responses to intraluminal stimuli in celiac disease.

Renal effects of gastrin C‐terminal tetrapeptide (as pentagastrin) and cholecystokinin octapeptide in conscious rabbit and man

“…Sodium paraaminohippurate (PAH) infusion and endogenous creatinine clearance were used to estimate ERPF and GFR, respectively (Calam et al, 1983 Laboratory analyses ofptasma and urine Previously described techniques (Calam et al, 1983) were used to measure electrolytes, including calcium and phosphate, PAH, creatinine, PCV and plasma renin activity (PRA; by radioimmunoassay). CCK8-like immunoreactivity concentrations (CCK8-LI) were determined by radioimmunoassay using a Cterminal specific CCK/gastrin antibody (Calam et al, 1982 …”

Post-translational processing of cholecystokinin in pig brain and gut.

“…Contained within peak A are three different fragments, one with COOH-terminal immunoreactivity and two having NH2-terminal immunoreactivity. The first of the NH2-terminal activity peaks (fractions [22][23][24][25][26] is probably spillover from peak B because refractionation of peak B on HPLC reveals a major NH2-terminal activity peak in this region. The second NH2-terminal activity peak may correspond to the peak 2 found in brain extracts.…”

“…Generally, acid extraction has been considered optimal for extraction ofintact CCK33 (23). In previous studies the tissues to be assayed generally have been divided in half, one part extracted for the acidic COOH-terminal fragments and the other extracted with an acid extractant for the more basic intact CCK or its NH2-terminal fragments (12,16,21,24). The method described in the present report has two principal advantages over those previously described: the amount of tissue available for extraction -is effectively doubled because both acidic and basic peptides are extracted from the same tissue; and methanol is equally as effective as boiling water or alkali in extracting the COOH-terminal fragments while minimizing the extraction of the larger CCK forms that occurs with the other extractants (16,24).…”

In Vitro Binding Assay of 31Methionine-oxidized Cholecystokinin Octapeptide to the CCKB Receptor

“…Phe-NH 2 ) accounts for 60% of the CCK family expressed in the human body and exhibits stronger activity than CCK33; in rats, it induces gallbladder contraction and amylase secretion in the pancreatic acini. [6][7][8][9] Binding site of CCK with its specific receptors is known to exist around the C-terminal region, which involves two methionine (Met) residues, 28 Met and 31 Met. We previously reported that the hydroxyl radical generated in vitro (Fenton's reaction) or hydrogen peroxide (H 2 O 2 ) can oxidize 28 Met and 31 Met of CCK8 to produce a CCK8 sulfoxide or sulfone [ Fig.…”