cholecystokinin and Pituitary-Neoplasms

Patients with craniopharyngioma (CP) have disturbances of the hypothalamic-pituitary axis and serious comorbidities such as obesity. We hypothesized that the secretion of hormones regulating the nutritional status is altered in adult patients with CP compared with patients with non-functioning pituitary adenoma (NFPA).. WE INCLUDED 40 CP (50% MALES, MEAN AGE: 49.6±14.3 years) and 40 NFPA (72.5% males, mean age: 63.4±9.8 years) patients. We measured glucose, insulin, leptin, total ghrelin, peptide-YY (PYY) and cholecystokinin (CCK) during oral glucose tolerance test (OGTT). Fat mass (FM) was determined by dual X-ray absorptiometry.. Gender distribution was not significantly different, but CP patients were significantly younger (P<0.001). CP patients had significantly higher BMI and FM than NFPA patients (BMI 32±8 vs 28±4 kg/m(2), P=0.009 and FM 37±9 vs 33±9%, P=0.02). Fasting glucose level (84±12 vs 78±11 mg/dl, P=0.03), leptin (27.9±34.2 vs 11.9±11.6 μg/l, P=0.008) and leptin levels corrected for percentage FM (0.66±0.67 vs 0.32±0.25 μg/l%, P=0.005) were significantly higher in CP than in NFPA patients, whereas ghrelin was significantly lower (131±129 vs 191±119 ng/l, P=0.035). Insulin, PYY and CCK did not differ significantly between groups. After glucose load, leptin decreased significantly in CP patients (P=0.019). In both groups, ghrelin decreased significantly during OGTT (both P<0.001). The percentage decline was significantly smaller for CP. PYY and CCK increased equally after glucose in both groups.. Our patients with CP have more metabolic complications than our patients with NFPA. The levels of leptin and ghrelin at fasting status and after glucose seem to be altered in CP, whereas changes in insulin, PYY and CCK do not seem to be responsible for the metabolic changes in these patients.

Topics: Absorptiometry, Photon; Adenoma; Adult; Aged; Appetite Regulation; Blood Glucose; Body Fat Distribution; Case-Control Studies; Cholecystokinin; Craniopharyngioma; Female; Ghrelin; Glucose Tolerance Test; Humans; Insulin; Leptin; Male; Middle Aged; Obesity; Peptide YY; Pituitary Neoplasms

There is growing evidence that cholecystokinin (CCK) affects growth and differentiation of anterior pituitary cells, via the CCK-B receptor. The possibility of an autocrine / paracrine role for CCK to modulate hormone secretion in human pituitary tumour cells is demonstrated here by RT-PCR and direct sequencing. In support of this conclusion, a neutralising antibody against the CCK peptide exhibited a dose dependent inhibition of hormone secretion by functionless pituitary adenomas. Total RNA was extracted from human pituitary adenomas, reverse transcribed into cDNA and subjected to PCR using primers specific for the gene for CCK, CCK-A and CCK-B receptors. PCR bands of the predicted length were observed in all tumours using human CCK gene and CCK-B receptor primers. Restriction digestion and direct sequence analysis provided further evidence that they represented both the human CCK peptide along with the CCK-A and/B receptor mRNA. CCK-33 and CCK octapeptide sulphate (CCK-8s) both powerfully stimulated phosphatidylinositol hydrolysis, providing evidence for functional activity of the CCK-A and/B receptors. A direct stimulatory effect of CCK peptides on both LH and FSH secretion is reported for the first time, whereas stimulatory effects on GH were blocked by antagonists to CCK. These results may indicate an autocrine role for CCK in the functioning and perhaps development of human pituitary tumours.

Topics: Adenoma; Adult; Aged; Autocrine Communication; Cholagogues and Choleretics; Cholecystokinin; Female; Gene Expression Regulation, Neoplastic; Gonadotropins; Growth Hormone; Humans; Male; Middle Aged; Neoplasm Proteins; Peptides; Pituitary Neoplasms; Receptor, Cholecystokinin A; Receptor, Cholecystokinin B; Tumor Cells, Cultured

Human teratocarcinoma Ntera2/c 1.D1 (NT2) cells express very low levels of the prohormone convertase enzyme PC1, moderate levels of PC2 and significant levels of PC5. When infected with an adenovirus which expresses rat CCK mRNA, several glycine-extended forms were secreted that co-eluted with CCK 33, 22 and 12. Amidated CCK is not produced because these cells appear to lack the amidating enzyme. Pituitary GH3 cells express high levels of PC2 and PC5. CCK adenovirus-infected GH3 cells secrete amidated versions of the same peptides as NT2 cells. Differentiation of NT2 cells into hNT cells with retinoic acid and mitotic inhibitors increased expression of PC5 and decreased expression of PCI and PC2. CCK adenovirus-infected differentiated hNT cells also secrete glycine extended CCK products and the major molecular form produced co-eluted with CCK 8 Gly. These experiments demonstrate that the state of differentiation of this neuronal cell line influences its expression of PC 1,2, and 5 and its cleavage of pro CCK and suggests that these cells may make an interesting model to study how differentiation alters prohormone processing. These results also support the hypothesis that PC5 in differentiated neuronal cells is capable of processing pro CCK to glycine-extended CCK 8.

Topics: Aspartic Acid Endopeptidases; Blotting, Western; Cell Differentiation; Cholecystokinin; Chromatography, Gel; Gene Expression Regulation, Enzymologic; Humans; Neurons; Pituitary Neoplasms; Proprotein Convertase 2; Proprotein Convertase 5; Proprotein Convertases; Protein Precursors; Protein Processing, Post-Translational; Serine Endopeptidases; Subtilisins; Teratocarcinoma; Tumor Cells, Cultured

Brain/gut cholecystokinin (CCK) has well-established translational and post-translational differences. By contrast, CCK transcription regulation is reported to be the same in brain and gut. Accordingly, the rat CCK gene has been evaluated for differential brain/gut transcription initiation. Using the 5'-flanking region of the rat CCK gene, DNase I protection assays were performed. We evaluated reporter constructs deleted of the conventional transcription start site in cell culture. Finally, brain and gut mRNA was evaluated using both a reverse transcription serial primer polymerase chain reaction assay as well as rapid amplification of cDNA ends (RACE) analysis. TFIID protein protects against DNase I digestion between -177 and -196 bp. In tissue culture, spontaneous 5'-flanking region transcription initiation occurs until deletion proceeds upstream of -140 bp. RACE analysis performed on mRNA from the rat brain identifies heretofore undescribed transcription initiation at -43 bp 5' as well as at +1,212 (in exon II). These alternative transcription initiation sites are utilized in brain, but not gut. The rat CCK gene has alternative 5'-flanking region transcription initiation sites. These alternative sites are utilized only in the brain. These data may provide insights into how brain and gut respond to their differing physiological demands.

Topics: Animals; Brain; Cholecystokinin; Cloning, Molecular; Genes, Reporter; Intestine, Small; Luciferases; Mutagenesis, Site-Directed; Organ Specificity; Pituitary Neoplasms; Polymerase Chain Reaction; Promoter Regions, Genetic; Rats; Recombinant Fusion Proteins; Sequence Deletion; Transcription, Genetic; Transfection; Tumor Cells, Cultured

Cholecystokinin (CCK) is detected in pituitary tumors but its role remains unknown. On the hypothesis that CCK may facilitate the cell growth in pituitary tumors, we have examined the effect of CCK on cell growth using a rat pituitary tumor cell line, GH3, cultured in a serum-free, chemically defined medium. Addition of sulfated CCK-(26-33) (CCK-8) in two different concentrations (0.5 approximately 1 nM) caused a significant increase in the number of GH3 cells. The antagonist (1 microM) for CCK-B receptor, but not CCK-A receptor, significantly inhibited the number of GH3 cells. Northern blot analysis revealed a significant expression of CCK-B receptor mRNA in GH3 cells, but not in normal rat pituitary glands. In addition, immunoreactive CCK/gastrin was detected by RIA in the GH3 cell extracts as well as the serum-free culture medium. In GH3 cell extracts, both CCK-8 and gastrin like peptides were identified by gel chromatography. These findings provided the first evidence for an autocrine/paracrine role of CCK and gastrin on stimulation of GH3 cell growth through the CCK-B receptor.

Topics: Animals; Blotting, Northern; Cell Division; Cholecystokinin; Chromatography, Gel; Dose-Response Relationship, Drug; Gastrins; Pituitary Neoplasms; Radioimmunoassay; Rats; Receptor, Cholecystokinin B; Receptors, Cholecystokinin; Time Factors; Tumor Cells, Cultured

The rat insulinoma RIN 5F and the mouse pituitary AtT-20 cell line, which are known to express several biologically active peptides, were found to express CCK mRNA, to correctly process, and to release immunoreactive cholecystokinin (CCK) peptides. They expressed low levels of these peptides (about 0.4 and 0.2 ng/mg protein, respectively) and both cell lines processed pro-CCK to a form which co-eluted with CCK 8 sulfate on Sephadex gel filtration chromatography and HPLC. The major CCK 8 immunoreactive peptide which they secreted co-eluted with CCK 8 on Sephadex G-50 chromatography. The secretion of CCK from both cell lines was significantly enhanced by treatment for 24 h with forskolin + IBMX (3-isobutyl-1-methyl-xanthine, a phosphodiesterase inhibitor). This treatment also doubled the CCK content of the AtT-20 cells. It appears that the ability of different endocrine tumor cells to express and process CCK is not as uncommon as previously thought. These cells should be useful for future studies of CCK expression, processing, and regulation of secretion.

Topics: 1-Methyl-3-isobutylxanthine; Animals; Blotting, Northern; Cholecystokinin; Chromatography, High Pressure Liquid; Colforsin; Cyclic AMP; Gene Expression; Insulinoma; Mice; Pancreatic Neoplasms; Pituitary Neoplasms; Protein Precursors; Rats; RNA, Messenger; Sincalide; Tumor Cells, Cultured

The development of gallstones is a well recognized complication of therapy with the long-acting somatostatin analogue, octreotide in patients with acromegaly. A group of nine acromegalic patients was treated with octreotide at doses of 300-600 micrograms daily for 8 months and the changes in fasting and post-prandial cholecystokinin release, and gall bladder motor function (determined by a radiosotopic technique) were assessed at regular intervals. In addition the development of any gallstones was determined by serial ultrasonography. Fasting cholecystokinin levels showed no significant change over 6 months, whereas the post-prandial levels demonstrated a significant decrease (p less than 0.01) during therapy, yet remained significantly higher than fasting levels. Twenty-four hours after commencing therapy gall bladder ejection fraction was decreased by 57 +/- 23 per cent and gall bladder ejection rate decreased by 63 +/- 19 per cent compared to the pretreatment values, whereas after 6 months' therapy a marked reduction in gall bladder ejection fraction (greater than 35 per cent) and gall bladder ejection rate (greater than 40 per cent) persisted in only four of nine patients. Three of these four patients with persistently impaired gall bladder motor function were subsequently shown to have developed either gallstones or biliary sludge during the course of therapy. We conclude that treatment with octreotide is associated with an impaired post-prandial release of cholecystokinin in all acromegalic patients, but gallstones only develop in those patients who, in addition, have evidence of a persistently impaired gall bladder motor response to cholecystokinin.

Topics: Acromegaly; Adult; Aged; Cholecystokinin; Cholelithiasis; Female; Gallbladder; Growth Hormone; Humans; Male; Middle Aged; Motor Neurons; Octreotide; Pituitary Neoplasms; Prospective Studies

Topics: Cholecystokinin; Humans; Pituitary Gland, Anterior; Pituitary Neoplasms

We found small amounts of cholecystokinin in the normal human adenohypophysis and therefore examined pituitary tumors from 87 patients with acromegaly, Cushing's disease, Nelson's syndrome, prolactinoma, or inactive pituitary adenomas. Five adenomas associated with Nelson's syndrome contained increased amounts of cholecystokinin, the concentrations being extremely high in two: 8281 and 13,453 pmol per gram as compared with less than 30 pmol per gram in normal pituitary glands. The cholecystokinin concentrations were moderately increased in adenomas from another 12 patients, of whom 5 had Cushing's disease and 7 acromegaly with adenomas containing ACTH. The cholecystokinin peptides from the tumors were smaller and less sulfated than cholecystokinin from normal pituitary glands. We conclude that ACTH-producing pituitary cells may also produce an altered form of cholecystokinin.

Topics: Acromegaly; Adenoma; Adrenocorticotropic Hormone; Cholecystokinin; Cushing Syndrome; Hormones, Ectopic; Humans; Nelson Syndrome; Pituitary Gland, Anterior; Pituitary Neoplasms; Prolactin

The processing of preprocholecystokinin in human pituitary extracts was investigated using gel and ion-exchange chromatography monitored by sequence-specific radioimmunoassays before and after incubation with trypsin, carboxypeptidase B, and arylsulfatase. Whereas the neural lobe contained only the bioactive alpha-carboxyamidated cholecystokinin (CCK) peptides (32 pmol/g), of which CCK-8 predominated, the anterior lobe contained substantial amounts of three large nonamidated procholecystokinin fragments (95 pmol/g; Mrs, 9000, 7000, and 5000) and small amounts of alpha-amidated CCK (8.3 pmol/g). The latter occurred only in the following large molecular forms: component I, CCK-58, and traces of CCK-33. Corticotrophic tumors processed the large forms to small CCK-8-like forms as are found in the brain and in the gut. The results show that a hormone gene, although translated, is expressed only to a limited extent as mature, active peptide outside the principal production region(s). Thus the processing of CCK to small alpha-amidated peptides in the less-differentiated tumor tissue supports the hypothesis that differentiation of endocrine cells may be sustained also at the posttranslational level.

Topics: Amino Acid Sequence; Cholecystokinin; Humans; Immune Sera; Peptide Fragments; Pituitary Gland, Anterior; Pituitary Neoplasms; Protein Precursors; Protein Processing, Post-Translational; Radioimmunoassay

Immunohistochemical and histological investigations were undertaken on 24 surgically-removed pituitary adenomas. By histology (haemalu-eosin staining), 7 chromophobe, 12 acidophil and 5 basophil pituitary adenomas were revealed. For immunohistochemical purposes the peroxidase-antiperoxidase technique was applied. Primary antisera against 10 hormones were used. By immunohistochemistry, 7 prolactin-containing, 2 TSH-containing, 2 GH-containing and 1 beta-endorphin-containing pituitary adenomas were identified. Furthermore, 1 mixed thyrotropic-prolactin human pituitary adenoma was detected. A possible connection between histological and immunocytochemical findings is discussed.

Topics: Adenoma; Cholecystokinin; Gastrins; Glucagon; Hormones, Ectopic; Humans; Immunoenzyme Techniques; Insulin; Insulin Secretion; Paraneoplastic Endocrine Syndromes; Pituitary Gland; Pituitary Hormones; Pituitary Neoplasms

Topics: Animals; Cells, Cultured; Cholecystokinin; Dopamine; Gastrointestinal Hormones; Humans; Pituitary Gland; Pituitary Neoplasms; Prolactin; Rats; Vasoactive Intestinal Peptide

Topics: Animals; Cholecystokinin; Growth Hormone; Hormones; In Vitro Techniques; Male; Pituitary Gland, Anterior; Pituitary Hormones, Anterior; Pituitary Neoplasms; Rats