A new mutation in the hepatocyte nuclear factor-1-alpha gene (P224S) in a newly discovered German family with maturity-onset diabetes of the young 3 (MODY 3). Family members carry additionally the homozygous I27L amino acid polymorphism in the HNF1 alpha gene.

Mutations in the hepatocyte nuclear factor-1-alpha gene cause maturity onset diabetes of the young 3 (MODY 3). Here we describe a new family affected by this disorder carrying the so far unknown mutation Pro224Ser in exon 3. First we identified a 17-year-old patient. OGTT demonstrated that insulin secretion was severely impaired: basal insulin was 3.7 uU/ml and 60 min after an oral glucose load plasma insulin peaked only threefold to 10.7 uU/ml. In addition, this patient carries the homozygous polymorphism Ile27Leu (exon1) in the hepatocyte nuclear factor-1-alpha gene that was shown to be associated with insulin resistance. So far, we have no evidence for insulin resistance in this individual patient. Additionally, two other family members carry the hepatocyte nuclear factor-1-alpha mutation Pro224Ser and the homozygous polymorphism Ile27Leu. A similar case with these two mutations in the HNF-1-alpha gene has not been described before. This data will allow to discover more patients with MODY 3.

[A 47-year-old man with "pure autonomic failure" and pernicious anemia]. / 47-jähriger Mann mit "pure autonomic failure" und Perniziosa.

HISTORY AND CLINICAL FINDINGS: A 47-year-old man with a known and substituted vitamin B12 deficiency presented with increasing symptoms associated with orthostatic hypotension, neck pain and micturitional and visual disturbances. CLINICAL AND LABORATORY TESTS: Catecholamines were strongly reduced in plasma and urine. DIAGNOSIS, TREATMENT AND CLINICAL COURSE: A pure autonomic failure was diagnosed and therapy with fludrocortisone, yohimbine and erythropoetine was started. Symptoms with the exception of micturitional disturbances improved strongly. CONCLUSIONS: Multiple-drug treatment of pure autonomic failure is successful. The prognosis is good.

Plasma resistin levels in patients with type 1 and type 2 diabetes mellitus and in healthy controls.

Resistin is a recently discovered hormone that is exclusively expressed in adipose tissue. Its expression in rodents was reported to be elevated or suppressed in genetic and diet-induced obesity, respectively. Resistin treatment impaired glucose tolerance and insulin action. Immunoneutralization of resistin improved insulin sensitivity, while thiazolidinedione treatment reduced resistin expression. Therefore, resistin could play a critical role in the development of obesity and type 2 diabetes. In this study were determined resistin plasma levels in humans suffering from type 1 and type 2 diabetes and in healthy controls. Plasma levels of resistin in healthy controls were 38.78 ng/ml. They were not statistically different in individuals with a broad BMI range. Resistin plasma levels in type 2 diabetes were 38.7 ng/ml, and 39.4 ng/ml in type 1 diabetes. Thiazolidinedione treatment did not influence resistin plasma levels. We conclude from our data: 1. resistin can be detected in human plasma, 2. plasma resistin levels are not different in type 1 and type 2 diabetes.

Effects of the nitric oxide/cGMP system compared with the cAMP system on airway mucus secretion in the rat.

Mucus secretion of the airways is under the control of a variety of intracellular second messenger systems. Cyclic nucleotides such as cGMP, coupled to the recently discovered nitric oxide system, and cAMP are of outstanding interest in this respect. The present study used the modified Ussing chamber technique and mucins labelled with (35)SO(4) to investigate mucus secretion in the rat trachea to clarify the contribution of these different second messenger systems to the control of mucin secretion.A variety of drugs affecting either the generation or the breakdown of the respective cyclic nucleotides were used. Neither drugs interfering with nitric oxide synthase nor the phosphodiesterase isoenzyme responsible for cGMP breakdown nor cGMP analogues were able to affect mucus secretion. In contrast, stimulation of adenylate cyclase or inhibition of the respective phosphodiesterase resulted in a potent increase of mucus secretion. In conclusion, we failed to show the involvement of the nitric oxide/cGMP system, whereas the cAMP system seems to be a very efficient regulator of mucus secretion in the rat trachea.

[The alpha-glucosidase inhibitor miglitol for the treatment of type 2 diabetes mellitus in the doctor's office]. / Der Alpha-Glukosidasehemmer Miglitol zur Therapie des Diabetes mellitus Typ 2 in der Praxis.

BACKGROUND AND METHOD: An observational study was carried out according to and 67 (6) AMG from october 1999 until august 2000. 2654 patients with diabetes mellitus type 2 were treated by 766 physicians for 3 months with alpha-glucosidase inhibitor miglitol. The aim of the study "DiaLife" was to obtain data regarding the effectiveness and safety of miglitol in the daily practice. Pre- and postprandial glucose levels, HbA1c, triglycerides, urin glucose, microalbuminuria and body weight were used as parameters of effectiveness. Also an increasing treatment scheme was used. Side effects were documented by the care providing physicians and evaluated by the global tolerability analysis. RESULTS: Males and females showed a balanced distribution. The average age was 62 years and the average duration of diabetes was 5 years. Concomitant diseases were described for 82% of patients: 62% of patients suffered from hypertension, 43% from hyperlipidemia and 22% from coronary heart disease. 64% of patients were already on treatment for diabetes. The mostly prescribed drugs were sulfonylureas and biguanides. Miglitol was gradually increased (first week 1 x 50 mg daily, second week 2 x 50 mg daily, until the third week 3 x 50 mg daily) and the final dosages were 3 x 50 mg or 3 x 100 mg miglitol daily. HbA1c, pre- and postprandial glucose levels were strongly reduced. The HbA1c decreased from 8.4% to 7,1%. Pre- and postprandial glucose levels were reduced minus 46 mg/dl and minus 59 mg/dl. The average decrease of body weight was 1,9 kg; the effect was augmented in individuals with higher BMI. Adverse effects were reported in 47 patients and occured mainly in the GI tract. There were no problems in the combination of miglitol with other pharmacological substance groups. CONCLUSION: The alpha-glucosidase inhibitor miglitol is an efficient and safe drug for the treatment of diabetes mellitus type 2. It is an ideal tool for mono- and combination therapy. It reduces remarkably the body weight. 90% of physicians judged miglitol's efficiency and safety as "very good" or "good".

mRNA expression patterns of insulin-like growth factor system components in human neuroendocrine tumours.

BACKGROUND: Insulin-like growth factors (IGF) and their corresponding receptors and binding proteins are important in carcinogenesis for several tumours, but their expression pattern in the functionally and biologically heterogeneous human neuroendocrine tumours of the gastroenteropancreatic tract is largely unknown. MATERIALS AND METHODS: This study searched for the mRNA expression patterns of components of the IGF system: IGF-1 and IGF-2, IGF receptors 1 and 2 (IGF-1R, IGF-2R), IGF-binding proteins 1-6 (IGFBP1-6)) in the most frequent human gastroenteropancreatic neuroendocrine tumours (gastrinomas, insulinomas, tumours associated with carcinoid syndrome and functionally inactive tumours) employing reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: In the 37 tumour samples analysed (nine gastrinomas, 10 insulinomas, nine tumours associated with carcinoid syndrome and nine functionally inactive tumours) IGFBP-2 was found in all tumour samples while the IGFBP-1 was expressed only at low frequency (10-22%) among the four tumour types. The IGF-2R was predominantly expressed in gastrinomas. Among the four tumour types the expression of IGF-1R, IGF-2R and IGFBP-6 varied significantly. In addition, 12 pairs of significantly coexpressed IGF system components were detected (IGF-1 <--> IGF-1R, IGF-1 <--> IGF-2R, IGF-1 <--> IGFBP-3, IGF-1 <--> IGFBP-6, IGFBP-3 <--> IGF-1R, IGFBP-6 <--> IGF-1R, IGFBP-1 <--> IGF-2R, IGFBP-3 <--> IGF-2R, IGFBP-5 <--> IGF-2R, IGFBP-3 <--> IGFBP-5, IGFBP-3 <--> IGFBP-6, IGFBP-5 <--> IGFBP-6). CONCLUSIONS: The described differences of the expression patterns of the IGF system components in neuroendocrine tumour subtypes suggest tumour type-dependent different pathways in tumour growth control by IGF system components.

Glucagon-like peptide-1 improves insulin and proinsulin binding on RINm5F cells and human monocytes.

Glucagon-like peptide-1-(7---36) amide (GLP-1) is a potent incretin hormone secreted from distal gut. It stimulates basal and glucose-induced insulin secretion and proinsulin gene expression. The present study tested the hypothesis that GLP-1 may modulate insulin receptor binding. RINm5F rat insulinoma cells were incubated with GLP-1 (0.01-100 nM) for different periods (1 min-24 h). Insulin receptor binding was assessed by competitive ligand binding studies. In addition, we investigated the effect of GLP-1 on insulin receptor binding on monocytes isolated from type 1 and type 2 diabetes patients and healthy volunteers. In RINm5F cells, GLP-1 increased the capacity and affinity of insulin binding in a time- and concentration-dependent manner. The GLP-1 receptor agonist exendin-4 showed similar effects, whereas the receptor antagonist exendin-(9---39) amide inhibited the GLP-1-induced increase in insulin receptor binding. The GLP-1 effect was potentiated by the adenylyl cyclase activator forskolin and the stable cAMP analog Sp-5, 6-dichloro-1-beta-D-ribofuranosyl-benzimidazole-3', 5'-monophosphorothioate but was antagonized by the intracellular Ca(2+) chelator 1,2-bis(0-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-AM. Glucagon, gastric inhibitory peptide (GIP), and GIP-(1---30) did not affect insulin binding. In isolated monocytes, 24 h incubation with 100 nM GLP-1 significantly (P<0.05) increased the diminished number of high-capacity/low-affinity insulin binding sites per cell in type 1 diabetics (9,000+/-3,200 vs. 18,500+/-3,600) and in type 2 diabetics (15,700+/-2,100 vs. 28,900+/-1,800) compared with nondiabetic control subjects (25,100+/-2,700 vs. 26,200+/-4,200). Based on our previous experiments in IEC-6 cells and IM-9 lymphoblasts indicating that the low-affinity/high-capacity insulin binding sites may be more specific for proinsulin (Jehle, PM, Fussgaenger RD, Angelus NK, Jungwirth RJ, Saile B, and Lutz MP. Am J Physiol Endocrinol Metab 276: E262-E268, 1999 and Jehle, PM, Lutz MP, and Fussgaenger RD. Diabetologia 39: 421-432, 1996), we further investigated the effect of GLP-1 on proinsulin binding in RINm5F cells and monocytes. In both cell types, GLP-1 induced a significant increase in proinsulin binding. We conclude that, in RINm5F cells and in isolated human monocytes, GLP-1 specifically increases the number of high-capacity insulin binding sites that may be functional proinsulin receptors.

Treatment of endocrine gastroenteropancreatic tumors with somatostatin analogues.

Somatostatin is a hormone that regulates the function of several exocrine and endocrine glands. The peptide mediates its actions via five different receptors. These proteins are expressed in a tissue-specific manner. Somatostatin receptors are also present in neuroendocrine gastroenteropancreatic tumors. Two long-acting somatostatin analogues, octreotide and lanreotide, are recognized by the receptor subtypes 2 and 5. Excessive hormone secretion in carcinoid syndrome can be controlled by these drugs. In addition, at least a subgroup of patients with carcinoid syndromes respond with delayed tumor growth during octreotide therapy. In the future, the availability of the somatostatin receptor cDNAs will allow the development of specific and even more potent receptor analogues.

[Treatment of type 2 diabetes mellitus with the alpha-glucosidase inhibitor Miglitol in the doctor's office]. / Die Therapie des Diabetes mellitus Typ 2 mit dem Alpha-Glukosidasehemmer Miglitol in der Praxis.

BACKGROUND AND METHOD: In an observational study carried out in accordance with paragraph 67 (6) of the AMG and beginning in May 1998, 846 patients with type 2 diabetes mellitus were followed for a period of three months by general practitioners and internists. The aim was to acquire data on the efficacy and tolerability of the alpha-glucosidase inhibitor, Miglitol, used in the doctor's office setting. A major point of interest was to determine the feasibility of using a regimen of gradually increasing doses in daily practice. The parameters investigated were HbA1c, fasting blood glucose and changes in the patient's weight. Any side effects were recorded by the care-providing physician and evaluated in the global tolerability analysis. RESULTS: The demographic data showed a balanced distribution of male and female patients. The average age of the men was 62 years, of the women 65 years. At the start of the observation, 62% of the patients had polyneuropathy, 35% retinopathy, and 25% nephropathy. 620 patients (73.3%) had received prior antidiabetic treatment. Depending on tolerability, the dose of Miglitol was increased individually from an initial 3 x 50 mg to 3 x 100 mg. 63.8% of the patients remained at the initial dose of 3 x 50 mg. A clear decrease in both HbA1c and fasting blood glucose was observed under treatment. During the course of the three months, the BMI decreased slightly by an average of 0.4 kg/m2, a desirable side effect in this patient group. Adverse reactions occurred in 39 ofthe 846 patients in the form of flatulence, diarrhea and enterospasm. CONCLUSION: Treatment with the alpha-glucosidase inhibitor Miglitol proved to be highly effective and readily combinable with other antidiabetics. Its efficacy was assessed to be "very good" or "good" by 86.5% of the physicians, and more than 90% assessed its tolerability to be "very good" or "good".

Plasma leptin levels do not change in healthy humans shortly after a hydrocortisone challenge.

The acute response of plasma leptin levels to a hydrocortisone challenge was measured in 16 healthy volunteers. We additionally asessed insulin which is known to play a regulatory role in the leptin system. While plasma cortisol levels increased significantly after the administration of hydrocortisone, this rise was not associated with any change in leptin and insulin concentrations during the 3.5-hour experimental period. This result corroborates the assumption that glucocorticoid-induced increases in leptin levels, as described in the literature, occur delayed and are due rather to an activation of leptin synthesis than to a mere leptin release.

A nutrient-regulated cytosolic calcium oscillator in endocrine pancreatic glucagon-secreting cells.

We investigated the influence of nutrients on spontaneous cytosolic calcium oscillations in InR1-G9 glucagonoma cells, a model for pancreatic alpha-cells. The oscillations depended on calcium release from stores and on calcium influx, partly through voltage-dependent calcium channels. Oscillations required the presence of at least 1 mM glucose, 50 microM alanine, or 50 microM glutamine, but were terminated by higher nutrient concentrations (40 mM glucose, or above 2 mM alanine or glutamine). The effects depended on the metabolism of the nutrients. Glutamine and alanine hyperpolarized the cells. This effect was inhibited (glutamine) or attenuated (alanine) by 1 mM ouabain. Our findings suggest that [Ca2+]i regulation in alpha-cells is dominated by slow oscillations induced by a lack of metabolic energy, resulting in decreased calcium export and storage, as well as increased calcium influx, partly due to depolarization caused by reduced sodium pump activity. These processes, leading to an elevated cytosolic calcium concentration, may mediate oscillations by calcium-induced calcium release from intracellular stores.

Effects of selective tachykinin-receptor antagonists on tachykinin-induced airway mucus secretion in the rat.

Tachykinins like substance P (SP), neurokinin A (NKA), neurokinin B (NKB) differentially stimulate airway mucus secretion with the following rank order of potency in rat trachea: SP>NKA>NKB. These differential actions are most likely due to different affinities to the tachykinin receptors, termed neurokinin (NK)(1), NK(2)and NK(3). In this study we characterized the receptor subtype responsible for the differential secretagogue effects in rat trachea by means of selective receptor antagonists and receptor agonists.SR 140333 [NK(1)-antagonist] completely inhibited SP action (283,29+/-21, 12%-->84,53+/-4, 09%; P<0,01) and significantly reduced the effects of NKA (179,08+/-17,34%-->118,86+/-6,7%; P<0,01) and NKB (171,89+/-5, 75%-->109,5+/-4,11%; P<0,01). SR 48968 [NK(2)-antagonist] did not affect SP action, but reduced the effects of NKA and NKB. SR 142801 [NK(3)-antagonist] did not change any effect of SP, NKA or NKB. [Sar(9)]SP (NK(1)-agonist) caused strong dose-dependent secretagogue effects similar to SP, [betaAla(8)]NKA (NK(2)-agonist) showed only slight and [Pro(7)]NKB (NK(3)-agonist) no effects. The present data suggest that the secretagogue effects elicited by tachykinins in rat trachea are mediated via NK(1)receptors.

High-level expression of the GLP-I receptor results in receptor desensitization.

Glucagon-like peptide-I (GLP-I) is a potent insulinotropic incretin hormone. Since the insulinotropic action of GLP-I is preserved in patients with diabetes mellitus, the peptide is now tested as new therapeutic agent for the treatment of diabetes. The number of GLP-I receptors present on B cells is regulated by several signal transduction pathways. In this study, we generated several Chinese hamster ovary (CHL) cell lines stably expressing different numbers of GLP-I receptors. The effects on binding properties and signal transduction were characterized. The lowest number of receptors was 1,791 per cell; the highest was 378,720 per cell. A comparable affinity against GLP-I was obtained with all clones. The three clones with the lowest numbers of receptors (1,791, 4,371, and 5,633 per cell) did not show any cyclic AMP (cAMP) generation in response to GLP-I (1 pM-1 microM). Cells expressing 13,175, 41,872, 271,003, and 378,720 receptors, respectively, increased cAMP concentration-dependently after GLP-I. The cell line with the highest number of receptors had the maximal response (352% of controls) but a dramatically reduced EC50 (100 nM, compared to 8 and 7 nM). All cell lines showed an identical cAMP response to 1 and 10 microM forskolin. These data demonstrate that a minimum number of GLP-I receptors is required for signal transduction. The GLP-I receptor is desensitized when expressed in high numbers on the cells. In this case, the signal transduction properties remain unchanged.

Effects of VIP and related peptides on airway mucus secretion from isolated rat trachea.

Vasoactive intestinal polypeptide (VIP) is known as an important regulator of airway function. It has been suggested that VIP is involved in the pathogenesis of asthma due to its relaxant effects on smooth muscles. The present study was designed to characterize the effects of the peptides of the VIP family on airway mucus secretion. The peptides VIP, PHI, PACAP-27, PACAP-38, GLP-I, exendin-4, helodermin, helospectin I and helospectin II were investigated using isolated rat trachea. Data show that PACAP-27 is the most potent stimulator of airway mucus secretion (225% stimulation). The rank order of potency was PACAP-27 > VIP > helospectin II > PHI > exendin-4 = helodermin = helospectin I = PACAP-38. The addition of the protease inhibitor thiorphan enhanced the effects of PHI and helodermin, but not of the other peptides. These data show that the peptides of the VIP family stimulate airway mucus secretion differently.

Growth factor receptor expression in human gastroenteropancreatic neuroendocrine tumours.

BACKGROUND: Human gastroenteropancreatic neuroendocrine tumours are functionally and biologically heterogeneous, but their exact growth factor receptor expression pattern, important for onco- and carcinogenesis, remains unknown. METHODS: This study searched for the mRNA expression pattern of six tyrosine- and serine/threonine kinase receptors [hepatocyte growth factor (HGFR), fibroblast growth factor (FGFR), epidermal growth factor (EGFR), insulin-like growth factor (IGF)-1R, transforming growth factor (TGF)-betaR1, TGF-betaR2] together with the five somatostatin receptors in human gastroenteropancreatic neuroendocrine tumours (gastrinomas, insulinomas, tumours with carcinoid syndrome, functionally inactive neuroendocrine tumours) using reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: EGF receptor was expressed almost exclusively in gastrinomas. Among the four tumour subtypes, expression frequencies of the somatostatin receptors 1 and 5, HGF-, IGF-1-, TGF-betaR1, TGF-betaR2 and the EGF-receptor varied significantly. CONCLUSIONS: In spite of the common cellular origin of these tumours, differences in growth factor receptor expression suggest the existence of different pathways during tumour subtype development.