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)

Insulin, proinsulin, glucagon and gastrin were determined in extracts of tumors of 27 patients with pancreatic islet cell neoplasia of pancreas, in one patient with nesidioblastosis, in extracts of uninvolved portions of the pancreas in 11 of the tumor patients and of 15 control pancreases. Mean insulin concentration in solitary adenomas and in adenomas of patients with adenomatosis was higher than in control pancreases; however, in all but 1 patient the insulin concentration in neoplastic islet tissue was lower than in islet tissue of control pancreas, assuming islet volume is 1% of pancreas. The percentage of proinsulin was elevated in 52% of tumors. Adenoma insulin content correlated with increments of plasma insulin after tolbutamide administration. Insulin and proinsulin concentrations in pancreas uninvolved by tumor were not suppressed. Fasting plasma glucagon was elevated in patients with islet cell adenomatosis and in patients with islet cell carcinoma some of whom had multiple endocrine adenomatosis. The mean concentration of glucagon in tumors was lower than in control pancreases. Elevated concentration of gastrin was found in some adenomas. The data indicate: 1) insulin-secreting islet cell tumors have decreased storage capacity for insulin, 2) elevated concentration of proinsulin in tumors may be due to decreased capacity to store insulin and in some to decreased conversion of proinsulin to insulin as well, 3) tolbutamide stimulates the exaggerated release of a relatively constant fraction of insulin stored in adenomas. 4) solitary adenomas may contain excess amounts of pancreatic hormones in addition to insulin, 5) elevated plasma glucagon in patients with organic hyperinsulinism may indicate malignancy, microadenomatosis or multiple endocrine adenoma syndrome, and 6) chronic hyperinsulinism and hypoglycemia due to adenoma do not suppress insulin and proinsulin content of uninvolved pancreas.
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PMID:Insulin, proinsulin, glucagon and gastrin in pancreatic tumors and in plasma of patients with organic hyperinsulinism. 1 70

Adult rats were rendered diabetic by a single iv injection of streptozotocin (70 or 75 mg/kg). In these rats, serum insulin fell to minimal levels during the 48 h following drug treatment, and this was roughly paralleled by a progressive decrease in the ability of the lung to oxidize glucose. The addition of insulin to diabetic rat lung slices in vitro had no restorative effect on the depressed glucose oxidative rate during a 2 h incubation period; however, two daily treatments of the rats with 1 unit of protamine, zinc insulin completely restored lung glucose oxidation rate to normal, without significantly reducing the hyperglycemic state of the rats. An examination of the temporal changes in glucose utilization by the rat lung after acute insulin treatment revealed that the diabetic lung responded directly to serum levels of insulin, whereas the normal lung appeared to be unaffected by serum insulin levels as hihg as 87 ng/ml. The reduced rate of glucose oxidation in the diabetic lung was apparent after perfusion of the lung with glucose-free medium, and was characterized by a significant reduction in Vmax without an alteration in Km. This was attended by a depressed ability of the lung to incorporate [3H]leucine into protein and an increased ability to produce lactate, but hexose monophosphate shunt activity was normal. Specific receptors for insulin have been identified and partially characterized in crude membrane preparations of normal rat lung. The interaction of insulin with these receptors was rapid, reversible, saturable, and was dependent upon time and temperature. The binding of labeled insulin was inhibited by low concentrations of unlabeled insulin and by high concentrations of proinsulin, whereas it was unaffected by the presence of glucagon, gastrin, prolactin, ACTH, or growth hormone in microgram amounts. These observations suggest that insulin regulates the transport and utilization of glucose in the rat lung, and that this tissue contains specific receptors for insulin.
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PMID:Pulmonary insulin responsivitiy: in vivo effects of insulin on the diabetic rat lung and specific insulin binding to lung receptors in normal rats. 14 46

The infusion of calcium results in the release of gastrin, calcitonin, and serotonin from certain nonbeta islet cell tumors of the pancreas, medullary carcinomas of the thyroid, and carcinoid tumors, respectively. In this study, intravenous infusion of either calcium chloride or calcium aluconate in a patient with an islet-cell carcinoma resulted in a simultaneous rise in plasma immunoreactive insulin and proinsulin, and concurrent hypoglycemia. After resection of the tumor, calcium infusion caused no change in these parameters. Similarly, calcium infusion caused no change in plasma insulin or glucose in normal volunteers. The response of this tumor suggests that calcium infusion may be a useful provocative test to detect insulin-secreting neoplasia. A derangement of the stimulus-secretion coupling mechanism for insulin in the tumor cells may be responsible for their abnormal sensitivity to calcium ion.
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PMID:Insulin and proinsulin release during calcium infusion in a patient with islet-cell tumor. 16 54

To assess the age of clinically detectable onset of multiple endocrine neoplasia type 1 (MEN 1), 88 members of four families were invited to participate in a ten-year biochemical screening program. Evidence for clinically detectable MEN 1 was found in adolescence. Pancreatic endocrine dysfunction constituted the presenting lesion in a majority of these individuals. The age at diagnosis of pancreatic endocrine tumors averaged 25 years and was lowered by almost two decades by prospective investigation. Furthermore, the penetrance of the pancreatic endocrine and parathyroid lesions equaled the penetrance found in autopsy studies. The use of a standardized meal stimulation test with the measurement of serum pancreatic polypeptide (PP) and gastrin responses resulted in diagnostic sensitivities of 75% and 100%, respectively. In addition to basal serum PP and insulin values, the proinsulin level was predictive for early pancreatic involvement in MEN 1. Serum gastrin was another useful tumor marker but only in the patients with pancreatic tumors diagnosed outside the prospective investigation. Two of the four MEN 1 kindreds selected for the screening investigation displayed homogeneity within families with respect to the profile of peptide excess and malignant potential of the pancreatic endocrine lesion, while the remaining kindreds demonstrated variable MEN 1 traits.
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PMID:Prospective screening in multiple endocrine neoplasia type 1. 136 98

A total of 80 individuals in 4 kindreds with multiple endocrine neoplasia type 1 (MEN 1) have been subjected to repeated biochemical screening during a 10-yr period with the principal aim being to analyze characteristics of the developing pancreatic lesion. Age at presentation of the MEN 1 trait averaged 18 yr in 7 previously unaffected individuals, and this effect of the screening procedure represented a lowering by almost 2 decades. Pancreatic endocrine involvement was recognized at a mean age of 25 yr and constituted the presenting lesion in a majority of the patients. A standardized meal test and basal values of serum pancreatic polypeptide, insulin, proinsulin, and gastrin were the most efficient markers for the pancreatic lesion and preceded signs of pancreatic tumors upon radiological examinations by a mean of 3.5 yr. A 75% penetrance of the islet cell disease and 90% for primary hyperparathyroidism within the affected individuals equalled the prevalences reported in autopsy studies. Two of the kindreds showed signs of intrafamilial homogeneity with respect to the profile of peptide excess (P less than 0.05) and considerable discrepancy in the malignant potential of the pancreatic lesions. The results of early detection and surgical intervention of the pancreatic tumors in MEN 1 suggested an impact on morbidity, while any effect on the mortality of these individuals remains to be clarified.
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PMID:Multiple endocrine neoplasia type 1: a 10-year prospective screening study in four kindreds. 167 62

Seventeen human subjects fasted without electrolyte replacement for 3 days and hormone levels were measured before, during and after the fast. Immediate consequences of the fasting state in healthy human subjects include a marked increase in plasma cortisol. ACTH, beta-endorphin, beta-lipotrophic hormone, adrenaline, noradrenaline and dopamine. Levels of all these hormones were much greater on the first morning of the fast than in the post-prandial state, even though the plasma glucose level was no lower than that observed on the morning before the fast began. A clear fall in TSH and tri-iodothyronine (T3) levels was observed, but thyroxine levels did not change significantly. Insulin levels fell whereas proinsulin levels did not fall during the fast, though they did rise markedly upon re-feeding. An increase in GH levels was particularly apparent in male subjects, but was also seen in females when evening samples were compared. Pancreatic glucagon showed a modest rise during the fast, but fell again on refeeding; total glucagon also rose as the fast proceeded, but increased markedly upon re-feeding. Levels of gastrin and peptide YY remained low during the fast. Plasma electrolyte levels were unchanged. The following were closely correlated: cortisol with ACTH, T3 with log10 TSH, dopamine with noradrenaline, and (negatively, during the fast) pancreatic glucagon with glucose.
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PMID:The effect of a 72-h fast on plasma levels of pituitary, adrenal, thyroid, pancreatic and gastrointestinal hormones in healthy men and women. 292 6

Sera from 15 patients with the Zollinger-Ellison syndrome were subjected to gel filtration on Sephadex G-50 superfine columns (10 x 2000 mm). The concentration of gastrin in the effluent was determined by a sensitive radioimmunoassay. Immunoreactive gastrin was eluted in four components in 14 sera. (1) Component I, eluted in the same position as proinsulin, constituted 9.7 +/- 1.2 (mean +/- SEM)% of the total immunoreactivity. (2) Component II (;big gastrin') eluted between proinsulin and insulin constituted 57.8 +/- 4.1% (mean +/- SEM) of immunoreactive gastrin. In three sera with the highest concentration of gastrin, component II appeared biphasic. (3) Component III (;little gastrin') was distributed in two peaks; the first one eluted in the same position as the heptadecapeptide gastrin II made up 17.4 +/- 2.7 (mean +/- SEM)% of the total immunoreactivity; the second one eluted in the same position as gastrin I constituted 9.5 +/- 1.3 (mean +/- SEM)%. (4) Component IV (;minigastrin') was eluted immediately before the salt peak and constituted 5.6 +/- 1.4 (mean +/- SEM)%. In one serum only components I and II were present. After incubation with trypsin all immunoreactivity in components I and II was converted to heptadecapeptide-like gastrins.The findings suggest that immunoreactive gastrin in serum from Zollinger-Ellison patients is circulating in at least four components of different molecular size.
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PMID:Gel filtration studies on immunoreactive gastrin in serum from Zollinger-Ellison patients. 419 48

The apparent molecular size and charge of immunoreactive gastrin components were studied in sera from patients with pernicious anaemia or gastrinomas (the Zollinger-Ellison syndrome) by Sephadex gel filtration and aminoethylcellulose chromatography. The following serum components were distinguished: (1) a monophasic component I similar in size to proinsulin which was converted into ;little' gastrin I by trypsin digestion; (2) a biphasic component II, corresponding to ;big' gastrins I and II (Gregory and Tracy); (3) a biphasic component III corresponding to ;little' gastrins I and II (Gregory and Tracy); and (4) a biphasic component IV, corresponding to ;minigastrins' I and II (Gregory and Tracy). ;Big, big' gastrin, a plasma component found in the void volume of the Sephadex G-50 column by Yalow and Berson (1972) was undetectable in the sera investigated. A component in gastrinoma and antral mucosa extracts corresponding in size to ;big big' gastrin was detectable by the assay; the ;big big' gastrin fraction from gastrinoma tissue was heterogenous, with components of apparent MW 30 000-100 000. It is concluded that serum gastrin circulates in the form of at least four components, of which the three smaller ones are in pairs.
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PMID:Immunoreactive gastrin components in human serum. 482 Jun 33

Many small biologicaly active peptides are derived from larger precursor forms which fulfil a variety of roles in the synthesis, segregation and intracellular migration of secretory products. Limited proteolysis may occur at several stages during this process, giving rise to products that are either degraded (e.g. the prepeptides) or discharged coordinately from their cells of origin during exocytosis (e.g. insulin and C-peptide). Molecular defects have recently been found to occur at cleavage sites in proinsulin as well as in other proproteins, and these point mutations may, in some instances, be responsible for familial metabolic disorders. The nature and cell specificity of the proteolytic enzymes involved in the conversion of the various precursor forms remains unresolved. Recent studies in our laboratory have led to the identification of precursors of glucagon and somatostatin in rat islets of Langerhans. Analysis of tryptic maps of these precursors has shown that a trypsin-like enzyme would be sufficient to cleave the C-terminally located somatostatin sequence from its precursor (relative molecular mass 12,500), but that both trypsin-like and carboxypeptidase B-like enzymes would be necessary to cleave the internal glucagon sequence from its prohormone (relative molecular mass 18,000). Molecular cloning techniques have provided valuable new approaches to analysing the structures of a variety of precursor forms, including those for insulin, gastrin, growth hormone, adrenocorticotropic hormone and the endorphins, and in the future will undoubtedly shed more light on the structures of their chromosomal genes, the mechanisms regulating their expression, and their evolutionary origins.
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PMID:Formation of biologically active peptides. 610 30

Mice carrying a Moloney murine sarcoma virus-(MSV) simian virus 40 large T transgene develop heritable tumors including endocrine pancreatic tumors. We have established several independent transgenic mouse lines expressing this transgene. One of these lines, designated MSV125, is characterized by the development of congenital cataracts and either pancreatic or brain tumors. The development and histopathology of the pancreatic tumors were studied by light microscopy and immunocytochemistry for large T antigen, neuron-specific enolase, insulin, proinsulin, glucagon, somatostatin, pancreatic polypeptide, gastrin, and serotonin. The 23 tumors examined were similar to human endocrine pancreatic tumors with respect to their macroscopic and histological features. We classified 91% of the tumors as insulinomas based on the predominance of insulin immunoreactivity. In newborn and young transgenic animals, nesidioblastosis and islet cell proliferation, consisting mostly of insulin containing beta cells, was obvious and persisted into adulthood. In transgenic animals more than 2 months old, islet hyperplasia and dysplasia predominated from which single tumors developed. Hyperplastic and dysplastic islets were composed mostly of beta cells. Large T antigen was detectable not only in tumor cells, but also in cells of normal and hyperplastic islets and in islet anlagen of newborn transgenic mice, indicating expression of the transgene in the endocrine part of the pancreas. Large T antigen-immunoreactivity was restricted to the beta cells. Insulinomas of the MSV-simian virus 40 T antigen-derived MSV125 transgenic mouse line may represent a valuable model for the study of the development and biology of insulinoma.
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PMID:Endocrine pancreatic tumors in MSV-SV40 large T transgenic mice. 838 73


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