A case with glucagonoma syndrome--heterogeneity of glucagon and insulin

The heterogeneity of glucagon and insulin in plasma and tissue extracts from a 57-year-old female with glucagonoma syndrome with surgically and autopsy verified islet-cell tumors was studied by Bio-Gel P-10 filtration. The preoperative plasma immunoreactive glucagon (IRG) level was 20.2 ng/ml, and plasma glucagon-like immunoreactivity(GLI) 25.8 ng/ml. The column chromatography of the preoperative plasma revealed three or four IRG components and four GLI components. Among these, peak II, the large glucagon immunoreactivity (LGI) peak, considered a candidate for proglucagon, was prominent, along with peak III. The resected metastatic liver tumor contained an enormous amount of IRG and an appreciable amount of immunoreactive insulin (IRI), indicating that the elevated plasma IRG was mainly of tumor origin. The IRG pattern of the tumor tissue extract revealed a small quantity of IRG in peaks I and II, and a large amount in peak III; control pancreatic tissue extract manifested a similar elution pattern. The IRI elution pattern of the tumor tissue extract revealed two major IRI peaks which migrated close to the elution volume of cytochrome C and insulin, respectively. This is a quite different pattern from the control pancreatic tissue extract in which the RI peak was localized in the elution volume of the insulin. We conclude that the present metastatic liver tumor produced not only enormous amounts of glucagon but heterogeneous peptides which contained immunological insulin determinants within their.     

Size heterogeneity of immunoreactive glucagon during bile-duct obstruction in the rabbit

The influence of bile-duct obstruction upon basal plasma glucagon levels and the relationship between glucagon-like substance in bile and postobstructive plasma glucagon were examined in the rabbit. Immunoreactive glucagon (IRG) was measured with antiserum 30 K (Unger). Bile-duct obstruction was followed by a prompt rise within 60 minutes in plasma IRG which was four times the basal value, but had little influence on plasma immunoreactive insulin and blood sugar. The biliary IRG and the elevated plasma IRG during bile-duct obstruction were filtered with a Bio-Gel P-10 column. Most of the postobstructive plasma IRG appeared in the void volume area (plasma large IRG), while almost all of the biliary IRG was recovered in the position equivalent to approximately 2000 daltons (biliary IRG 2000). Both IRGs of different molecular sizes revealed similar dilution curve in radioimmunoassay to that with porcine glucagon. After incubation of bile with preobstructive plasma, the IRG elution profile of the mixture contained an increased amount of large molecular size IRG similar to that of postobstructive plasma in regard to 30K specificity and elution position. The disappearance of IRG in the void volume area was observed when the bile-plasma mixture or the postobstructive plasma was filtered with acidic buffer. These results suggest that plasma large IRG contributing to hyperglucagonemia during bile-duct obstruction may be derived from biliary IRG 2000.     

Morphological changes in the human endocrine pancreas induced by chronic excess of endogenous glucagon.

The non-tumoral endocrine pancreas from a patient with elevated plasma levels of glucagon due to a malignant glucagonoma was studied immunocytochemically, ultrastructurally and morphometrically. Compared with normal pancreatic islets from control subjects, those of the pancreas from the patient with a glucagonoma showed an almost complete disappearance of A cells, a decrease in immunoreactive insulin in B cells associated with cytological features indicating enhanced synthesis and secretion of this hormone, and an increase in immunoreactive somatostatin and pancreatic polypeptide (PP) accompanied by unusually high numbers of D and PP cells. In addition, numerous B cells were found outside the islets, either forming micro-islets or scattered in the exocrine tissue (nesidioblastosis). The possible mechanisms involved in determining the changes in the secretory activity of B cells and the alterations in the cell composition of the islets are discussed.     

Heterozygous Men1 mutant mice develop a range of endocrine tumors mimicking multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary syndrome characterized by the occurrence of multiple endocrine tumors of the parathyroid, pancreas, and anterior pituitary in patients. To study tumorigenesis related to the MEN1 syndrome, we have generated Men1 knockout mice using the gene targeting approach. Heterozygous Men1 mutant mice developed the same range of major endocrine tumors as is seen in MEN1 patients, affecting the parathyroid, pancreatic islets, pituitary and adrenal glands, as well as the thyroid, and exhibiting multistage tumor progression with metastatic potential. In particular, extrapancreatic gastrinoma, pancreatic glucagonoma, and mixed hormone-producing tumors in islets were observed. In addition, there was a high incidence of gonadal tumors of endocrine origin, i.e. Leydig cell tumors, and ovary sex-cord stromal cell tumors in heterozygous Men1 mutant mice. Hormonal disturbance, such as abnormal PTH and insulin levels, was also observed in these mice. These tumors were associated with loss of heterozygosity of the wild-type Men1 allele, suggesting that menin is involved in suppressing the development of these endocrine tumors. All of these features are reminiscent of MEN1 symptoms in humans and establish heterozygous Men1 mutant mice as a suitable model for this disease.     

A single-centre experience with octreotide in the treatment of different hypersecretory syndromes in patients with functional gastroenteropancreatic neuroendocrine tumors

The aim of this research was to assess the clinical and biochemical efficacy of the octreotide in the treatment of patients with various functional gastroenteropancreatic neuroendocrine tumors (GEP-NETs). The study included 14 patients treated with octreotide for 6 months. They were diagnosed with VIPoma, glucagonoma, gastrinoma, medullary thyroid carcinoma (solitary and as a part of MEN-II syndrome), pancreatic carcinoids (solitary and as a part of multiple endocrine neoplasia type-1 syndrome-MEN-1 syndrome) and midgut carcinoids. The patients presented with Verner-Morrison, glucagonoma, Zollinger Ellison and carcinoid syndrome respectively. All had a metastatic disease at the time of diagnosis and a positive octreoscan finding. Initially elevated chromogranin A (CgA) levels were detected in 11 (78.6%) and elevated 5-hydroxyindolacetic acid (5-HIAA) levels in 8 (57.1%) patients. Symptomatic efficacy assessments were made by diarrhea reductions during treatment course, and laboratory efficacy was assessed through changes in 5-HIAA and CgA levels. Assessments were made initially and following 6 months of therapy. Median urinary 5-HIAA and the number of stools decreased significantly (p = 0.016 and p = 0.009 respectively, p < 0.05) while CgA levels had the decreasing tendency but not statistically significant (p = 0.14). There was a positive correlation between the 5-HIAA reduction and the decrease in stool number at baseline and during treatment course (p < 0.05). No correlation was observed between 5-HIAA and CgA levels and also there was no correlation between CgA reduction and symptomatic improvement. The results prove octreotide to be effective in reducing symptoms and biochemical markers associated with hypersecretory syndromes of GEP-NETs.     

Pharmacokinetics and effects of intravenous infusion of somatostatin in normal subjects--a two-compartment open model

A direct radioimmunoassay of plasma somatostatin-like immunoreactivity (SRIF-LI) was developed and validated. The sensitivity was 16.0 pg/ml, and the specificity was good. The recovery of plasma SRIF-LI was 98.8 +/- 6.3%. The Scatchard plot of the antiserum binding data revealed a straight line, with a binding affinity of 3.52 X 10(-12) M and a binding capacity 4.06 X 10(-10) M. Synthetic SRIF (Stilamin), 250 micrograms, was infused intravenously over a 30-min period in 9 healthy volunteers. Plasma glucose, insulin (IRI), glucagon (IRG) and SRIF-LI were measured. A two-compartment open model was adopted to analyze the pharmacokinetic data of SRIF-LI. The results showed that plasma SRIF-LI rose from 192.2 +/- 16.2 pg/ml to a plateau of 2,129.8 +/- 288.2 pg/ml within 5-10 min after starting the infusion. The half disappearance time from plasma (Ta1/2) was 1.36 +/- 0.18 min, the half disappearance time from the 'remote' compartment (Tb1/2) was 49.6 +/- 10.9 min and the net half disappearance time from the two compartments together (Tn1/2) was 9.19 +/- 1.49 min. The metabolic clearance rate was 50.3 +/- 7.0 ml/kg/min. The plasma IRI, IRG and the IRI/IRG molar ratio were all suppressed during the infusion period. The recovery time of plasma IRG was mildly delayed in comparison to that of IRI. This indicates that there are dissociations between IRI and IRG in the extent and the duration of suppression caused by somatostatin infusion.     

A case of asymptomatic cortisol producing adrenal adenoma.

We describe a man without the clinical findings of Cushing's syndrome, but who harbored an incidentally found cortisol-producing adrenal adenoma. On adrenal 131I-adsterol imaging, there was good uptake to the nodule, but no visualization of the contralateral adrenal. No abnormalities were found in the basal plasma cortisol, ACTH, urinary free cortisol and 17OHCS. However, dynamic hormone assessment revealed the existence of abnormal cortisol secretion: no suppression to dexamethasone, incomplete response to human corticotropin-releasing hormone, and lack of diurnal variation in plasma cortisol. Left adrenalectomy was performed with the diagnosis of cortisol-producing adrenal tumor. The pathological finding was an adrenal adenoma, and the perifusion of the excised tissues revealed a negligible response of the tumor tissue to ACTH though the residual normal cortex responded. Postoperative course was uneventful without replacement therapy with cortisol. It is suggested that the tumor autonomously produced a small amount of cortisol not only insufficient to provide clinical Cushing's syndrome, but also to provide typical suppression of hypothalamo-pituitary corticotroph-adrenal system.     

Effect of acute ethanol load on plasma immunoreactive insulin and glucagon.

The effect of a single large dose of ethanol (5 mg/kg body weight) on plasma glucagon (IRG) and insulin (IRI) concentrations was studied in rats fasting for 24 hr. Hepatic cAMP concentration and blood glucose were also estimated and correlated with hormonal changes. Plasma IRG concentrations had doubled by the first sampling time (2 hr) and remained at this level up to 16 hr after ethanol administration. Plasma IRI concentrations were not affected by ethanol. Hepatic cAMP concentrations reflected changes in the plasma insulin/glucagon ratio, which seems to be the major determining factor for hepatic cAMP even during ethanol oxidation. Hypoglycemia was not found in the ethanol group during the experimental period of 24 hr, and it was therefore concluded that ethanol may stimulate glucagon secretion in rats even without concurrent hypoglycemia. Possible mechanisms for the action of ethanol on the endocrine pancrease are discussed.     

Response of extrapancreatic immunoreactive glucagon to intraluminal nutrients in pancreatectomized dogs

To investigate the response of extrapancreatic glucagon to intraluminal stimuli, nutrients were administered to normal and pancreatectomized dogs through a stomach tube in a fully conscious state after an overnight fast. Plasma immunoreactive glucagon was determined with antisera specific and nonspecific to glucagon and was designated as IRG and total IRG, respectively. Oral glucose load elicited a decrease in plasma IRG and a remarkable rise of plasma total IRG in a group of 6 pancreatectomized dogs, as in the control dogs. When arginine was given, both plasma IRG and total IRG significantly increased in a group of 5 pancreatectomized dogs, while only total IRG rose significantly in the normal control dogs. Butter load did not reveal any changes in plasma IRG and total IRG in a group of 5 pancreatectomized dogs, whereas only total IRG increased in the normal control dogs. It is concluded that extrapancreatic glucagon responds to intraluminal administration of nutrients, as pancreatic glucagon does. In addition, gut glucagon-like immunoreactivity increased following glucose or arginine ingestion in pancreatectomized dogs. Furthermore, the failure in response of plasma IRG and total IRG to butter load in pancreatectomized animals suggests that its intraluminal hydrolysis is important in the secretion of extrapancreatic immunoreactive glucagon.     

The WDHA syndrome: clinical and laboratory data on 28 Japanese cases

During the period between 1967 and 1983, there were 28 WDHA patients in Japan. Clinically, these patients were not very different from those reported in western countries, but we have been able to add a few observations as follows. First, the WDHA patients with pancreatic endocrine tumors and those with neuroblastic tumors were present in almost equal numbers. Second, fluctuating hypercalcemia was often observed in patients with this syndrome, but it was not observed in any watery diarrhea due to the other etiologies. Third, the WDHA patients who have multiple endocrine neoplasia (MEN) type 1 have multiple tumors in the pancreas, indicating that the patients with MEN should be managed in a different manner in regard to determining tumor location as well as applying surgical treatment. When various types of tumors were examined for VIP content, it was found that many tumors have the potential to produce VIP, and when VIP is produced in large amounts, plasma VIP levels become elevated, resulting in the WDHA syndrome.     

Plasma glucagon-immunoreactive components in early life in dogs

High plasma concentrations of C-terminal immunoreactive glucagon (IRG) have been found during early life in several mammalian species. We have analyzed the plasma IRG of 12 h to 60 day-old dogs in terms of the 4 peaks (IRG greater than 20,000, IRG9000, IRG3500 and IRG2000) obtained by gel filtration on Bio-Gel P-30. Significant changes with age and in response to administered agents were confined to IRG9000 and IRG3500. IRG9000 was 9-fold higher in 12-36 h old dogs than in adults (108 +/- 24 pg/ml pancreatic glucagon equivalents v. 12 +/- 3 pg/ml, mean +/- SEM) and showed a decline to 2-fold higher (27 +/- 5 pg/ml) at 31-60 days. IRG3500 was higher than in the adult only during the first 36 h of life (36 +/- 5 pg/ml v. 15 +/- 3 pg/ml). Arginine infusion (0.5 g/kg over 15 min) caused an increase in plasma levels of both IRG9000 and IRG3500 in the newborn, whereas in adult dogs only IRG3500 was increased. Insulin injection (0.2 U/kg intravenously) causing a marked hypoglycemia had no significant effect on the plasma level of any IRG component in newborn dogs. Dihydrosomatostatin infusion (10 micrograms/kg bolus +/- 90 micrograms/kg over 30 min) caused a decrease in both IRG9000 and IRG3500. The increased basal level and secretory response to arginine of IRG9000 in newborn dogs may reflect an immaturity of the A cells, whereby more of this component, which may represent a precursor of pancreatic glucagon, is secreted than in the adult. The immature A cells also appear to have an impaired secretory response to hypoglycemia.     

Effect of subcutaneous pancreatic tissue transplants on streptozotocin-induced diabetes in rats. II. Endocrine and metabolic functions.

The present study examines the effect of subcutaneous pancreatic tissue grafts (SPTG) on endocrine and metabolic functions in streptozotocin (STZ)-induced diabetic rats using radioimmunoassay and biochemical techniques. SPTG survived even after 15 weeks of transplantation and significantly improved the weight of STZ-diabetic rats over a 15-week period. Although blood glucose-, cholesterol-, and glycosylated-haemoglobin (GHb) levels were not significantly lower in STZ-diabetic rats treated with SPTG, the values of these biochemical parameters were lower than those in untreated diabetic rats. Plasma and pancreatic immunoreactive C-peptide (IRCP) levels did not improve after SPTG (IRCP expressed as mean +/- standard deviation were 0.22 +/- 0.07, 0.072 +/- 0.02 and 0.08 +/- 0.03 pg ml-1 in the plasma non-diabetic diabetic and treated rats respectively, while IRCP levels in the pancreas of the non-diabetic, diabetic and treated rats were 433.8 +/- 0.1, 22.9 +/- 0.01 and 10.4 +/- 0.01 pg mg tissue-1 respectively). SPTG, however, improved plasma immunoreactive insulin (IRI) levels in both plasma and pancreas. IRI values in plasma were 54.7 +/- 13.6, 18.0 +/- 5.0 and 22.1 +/- 4.3 microUI ml-1 in non-diabetic, diabetic and treated rats respectively and were 277.3 +/- 37.1, 14.7 +/- 1.8 and 30.3 +/- 15.9 microIU micrograms tissue-1 in the pancreas of non-diabetic, diabetic and treated rats respectively. There was improvement in immunoreactive glucagon (IRG) levels after SPTG. IRG values in the plasma of non-diabetic, diabetic and treated rats were 147.0 +/- 10.7, 408.0 +/- 76.5 and 247.7 +/- 3 pg ml-1 respectively whereas, IRG measured in the pancreas was 1642.25 +/- 424.23, 1899.0 +/- 290.4 and 1714.1 +/- 301.98 pg micrograms tissue-1 in non-diabetic, diabetic and treated rats, respectively. The pancreas:plasma ratio of pancreatic hormones was deranged in untreated diabetes but improved after SPTG. In conclusion, SPTG significantly improved the weight gain, pancreatic insulin content, plasma IRG and pancreas: plasma ratio of IRCP, IRI and IRG. It also reduced blood glucose-, cholesterol-, and glycosylated-hemoglobin levels in STZ-diabetic rats.     

Secretory response and immunochemical heterogeneity of glucagon in plasma and tumor extracts of a patient with glucagonoma

The secretory response and immunoreactive heterogeneity of glucagon was investigated in a patient with glucagonoma syndrome. After glucose administration, abnormal insulin release accompanied by glucose intolerance were observed, whereas the high glucagon circulating levels were only partially blocked after glucose or somatostatin infusion. Chromatographic fractionation of plasma samples, before and after arginine administration showed that most of the immunoreactivity eluted as true glucagon. Furthermore, when aliquots of the tumor extracts were fractionated by column chromatography or by polyacrylamide gel electrophoresis, most of the immunoreactivity eluted in the 3,500 molecular weight peak. In contrast with previous reports, our results indicate that neoplasia A cells can also manufacture and release into the bloodstream great amounts of genuine glucagon rather than larger glucagon immunoreactive forms. In spite of such findings, in this patient neither diabetes nor hyperglycemia were present.     

Plasma Glucagon Levels Suppressed by a Glucose Load in a Man with Incidental Pancreatic Glucagonoma

ObjectiveTo describe a patient with a histologically proven pancreatic glucagonoma, noted incidentally during a follow-up visit for high aminotransferase levels, and to evaluate its autonomy with a standard 75-g oral glucose tolerance test.MethodsWe present the results of a 2-hour oral glucose tolerance test, with plasma glucagon and blood glucose levels measured every 30 minutes after an oral glucose load. In addition, we provide a brief review of the literature on the diagnosis and management of glucagonomas and the importance of long-term surveillance.ResultsIn our patient, who had a 1-year history of impaired fasting glucose, plasma glucagon levels were persistently suppressed to within the normal range after oral glucose challenge. Octreotide scintigraphy revealed abnormal uptake in the pancreatic tail, and a 2.8-cm mass was removed at laparoscopic distal pancreatectomy. Immunohistochemical staining of the tumor tissue showed intense reactivity for glucagon. Plasma glucagon levels were reduced to < 50 pg/mL postoperatively, and scintigraphic study at 4-month follow-up showed no residual uptake at the previous tumor site or elsewhere.ConclusionGlucagon-secreting pancreatic tumors are extremely rare. A substantially elevated plasma level of glucagon is usually seen in patients with metastatic tumors. In the early stage of a glucagonoma, however, the plasma glucagon level may be only modestly elevated and may still be susceptible to normal negative feedback inhibition. We demonstrated plasma glucagon complete suppressibility after oral glucose challenge in a patient with a glucagonoma, the first such report in the literature. (Endocr Pract. 2007;13:780-784)     

以疲乏为主诉的肿瘤内分泌副综合征一例并文献复习

目的:肿瘤内分泌副综合症是肿瘤病人需警惕的并发症,抗利尿激素分泌异常综合症是其较常见的一种,常无明显临床表现,容易忽视和漏诊,其与肿瘤发病率,死亡率相关.本文旨在探讨肿瘤内分泌副综合症的早期诊治以便有助于改善患者的生存质量及预后.方法:通过报道一例以疲乏为主诉的肿瘤副综合症并进行相关文献的回顾性复习与分析.结果:准确诊断内分泌副肿瘤综合症是临床医生必须高度重视的,对部分肿瘤内分泌副综合症为排除性诊断,需要完善的临床资料,不可轻易诊断.治疗以控制肿瘤为主结合控制引起综合症的内分泌原因.结论:肿瘤内分泌综合症需要受到临床医师重视,尽量减少漏诊误诊,完善资料准确诊断,积极治疗可改善预后.     

Autonomy of cortisol secretion in clinically silent adrenal incidentaloma.

Recent progress in non-invasive imaging techniques have resulted in an increasing frequency of adrenal incidentaloma discovery. In addition, even clinically silent adrenal tumor has been suggested to possess a subtle production of adrenal hormones. The aim of the study was to ascertain the autonomy of cortisol production in clinically silent adrenocortical incidentaloma. We investigated the hypothalamic-pituitary-adrenal axis in 38 patients with adrenal incidentaloma. Basal plasma cortisol level was reproducibly within normal range in all the patients with adrenal incidentaloma, but was also normal in half of the Cushing's syndrome cases studied. Eighteen of 38 patients showed plasma cortisol above 3 microg/dl after 1 mg dexamethasone (Dex) and above 1 microg/dl after 8 mg Dex, respectively, and were defined as preclinical Cushing's syndrome. These patients were subjected to further evaluation of the autonomy of cortisol production. The incidence of positive findings indicating autonomy of cortisol secretion was as follows: suppressed basal plasma ACTH level in 44%, loss of normal diurnal rhythm in 79%, lack of ACTH response to CRF in 35%, decreased plasma DHEA-S level in 28%, significant laterality of 131I-adosterol uptake in 75%, atrophy of the contralateral side of the adrenal on CT scan in 6%, and histological atrophy of the adjacent adrenal cortex in 56%, respectively. The endocrine feature relevant to the hypothalamic-pituitary-adrenal axis varied from patient to patient, ranging from the non-functioning adrenal adenoma to Cushing's syndrome. In addition, the results of each test did not coincide with others in each patient. These results clearly demonstrated that the incidence of autonomy of cortisol production in the clinically silent adrenal incidentaloma is not infrequent, showing significant diversity. Systemic evaluation of the hypothalamic-pituitary-adrenal axis before adrenal surgery is warranted for an appropriate glucocorticoid replacement after adrenal surgery.     

The effect of long-distance running on plasma immunoreactive glucagon levels

Twelve highly conditioned long-distance runners were studied to determine the effects of marathon (42 km) and 10,000 m running on plasma immunoreactive glucagon (IRG), serum immunoreactive insulin (IRI), and serum glucose (G) levels. Blood samples were drawn just prior to and immediately upon completion of the run. Marathon running resulted in no significant change in G, IRI, or IRG levels. After running 10,000 m, plasma IRG levels did not change significantly, while IRI and G increased significantly. In evaluating the pooled data from both runs, a significant inverse correlation was observed between delta G and delta IRG. This relationship between delta G and delta IRG suggests that glucagon plays a role in maintaining normal blood glucose levels during strenuous exercise.     

Diagnostic and therapeutic difficulties in MEN 1 syndrome

MEN 1 syndrome (Multiple Endocrine Neoplasia type 1) is a rare endocrine disorder characterized by the association of tumors in several endocrine glands, mainly in parathyroids, gut and pituitary. At our institution in the years 1982-2004 we have followed 26 patients with MEN 1 syndrome belonging to 19 families. The diagnosis of MEN 1 was based on Gubbio Consensus (JCEM 86: 5658-5671, 2001). Mean age at the diagnosis of MEN 1 was 35 years. Primary hyperparathyroidism was the most frequent pathology, which was diagnosed in 25 of 26 patients (96%). Gut endocrine tumors were found in 20 patients (77%), while pituitary tumors in 18 (70%). Non-functioning gut tumors were most frequent (n=9), followed by insulinoma (n=7) and gastrinoma (n=4). Prolactinoma was the most frequent pituitary tumor found in 12 patients (67%). Three patients died during the observation period - all of them of generalized gut endocrine tumor (gastrinoma in 2 cases and foregut carcinoid in one case). The management of MEN 1 is not easy and careful analysis of clinical picture is necessary in each individual case. Several important observations can be made on the basis of own experience and the literature: 1. In each sporadic pathology, which may be a part of MEN 1, one should consider. the possibility of MEN 1. The individual MEN 1 abnormalities are often diagnosed after 40 and later 2. MEN 1 tumor are usually multiple thus necessitating a different therapeutic approach (more radical surgery) 3. The most valuable screening tests are: Ca++, PP, CgA and prolactin 4. Endoscopic ultrasound is the most specific method for the localization of pancreatic endocrine tumors. 5. The results of surgical treatment of MEN 1 tumors are worse than that of sporadic tumors. 6. Prognosis in MEN 1 is determined by the behaviour of gut neuroendocrine tumor 7. No genotype/phenotype correlation in MEN 1 syndrome was found so far. In summary, it should be underlined that MEN 1 syndrome is an endocrine disorder, in which early diagnosis and optimal treatment may significantly improve the prognosis.     

Expression profile of human immune-responsive gene 1 and generation and characterization of polyclonal antiserum

Murine immune-responsive gene 1 (IRG1) plays significant roles in embryonic implantation and neurodegeneration. The expression pattern of the human IRG1 gene, however, has not yet been established, and the predicted gene sequence has been revised several times according to computed expressed sequence tags (ESTs). To determine the human IRG1 gene expression profile, human fetal tissue samples, peripheral blood mononuclear cells (PBMCs) from normal healthy subjects, and the human leukemia cell lines THP-1 and K-562 challenged with lipopolysaccharide (LPS) were subjected to RT-PCR using degenerate primers. The results indicated that the IRG1 gene is differentially expressed in human fetal PBMCs and LPS-stimulated adult PBMCs. The amplified gene fragment was cloned into the pET32a(+) vector and fusion-expressed with a His-tag in a prokaryotic system. After affinity chromatography, human IRG1h fusion proteins were isolated by SDS-PAGE and identified by mass spectrometric analysis for use as an immunogen to immunize rabbits. The titer and specificity of the purified rabbit antiserum were sufficient to measure human IRG1 gene expression in various tissues and cultures. This purified polyclonal antiserum will allow us to initiate studies to elucidate the biological roles of the human IRG1 gene.     

Antisera raised against eledoisin and kassinin detect elevated levels of immunoreactive material in plasma and tumor tissues from patients with carcinoid tumors

Radioimmunoassays based on antisera raised against the tachykinins eledoisin (antiserum E7) and kassinin (antiserum K12) were used to measure the concentration of tachykinin-like immunoreactivity (TKLI) in plasma from 52 healthy subjects. 65 patients with carcinoid tumors (of which 46 had symptoms of both flushing and diarrhoea), and 6 patients with endocrine pancreatic tumors. The antisera did not crossreact with substance P (SP). Elevated concentrations of TKLI, as compared with healthy subjects, were found in 75% of the carcinoid patients, but in none of the patients with pancreatic tumors. Tumor metastases from 8 of the carcinoid patients all contained TKLI. Ion-exchange chromatography of plasma samples and tumor tissue extracts indicated the presence of several immunoreactive molecular forms. The elution patterns of the immunoreactivity detected by antisera E7 and K12 were similar, indicating that the same molecular species are measured by these antisera. None of the components coeluted with synthetic SP. One of the immunoreactive components in carcinoid tumor extracts coeluted with synthetic NKA. The major immunoreactive components in plasma from the patients eluted in a position different from that of all currently known mammalian tachykinins. Tachykinin immunoreactive material detected in tumor tissue and plasma of patients with carcinoid tumor may play a role in the symptomatology of the carcinoid syndrome.