Significance of acid amyloglucosidase in sulphonylurea-induced insulin release

Summary The effect of exogenous acid amyloglucosidase on sulphonylurea-induced insulin release was investigated in mice and rats. 1. Pretreatment of mice with acid amyloglucosidase enhanced insulin release induced by the different sulphonylurea derivatives, carbutamide, tolbutamide, glibenclamide, and glibornuride. 2. A dose-response relationship between glibenclamide-induced insulin response and amyloglucosidase dosage covering a 64-fold concentration range was established in mice. 3. Pretreatment of the animals with other macromolecules of similar physiological or chemical properties to acid amyloglucosidase such as-amylase,-glucuronidase and albumin did not influence glibenlamide-induced insulin release. 4. The effect of acid amyloglucosidase pretreatment on insulin release induced by different agents known to affect the islet-cell adenylate cyclase-cyclic AMP system such as secretin, L-isopropylnoradrenaline (L-IPNA), arginine, glibenclamide and 3-isobutyl-1-methylxanthine (IBMX) was tested. It was observed that in animals pretreated with acid amyloglucosidase, insulin release was enhanced when stimulated by glibenclamide, a phosphodiesterase inhibitor, but it was similarly enhanced by arginine, a phosphodiesterase activator. Insulin release induced by secretin, L-IPNA, and IBMX was unaffected. 5. Acid amyloglucosidase pretreatment in rats enhanced plasma immunoreactive insulin levels following glibenclamide injection not only in the peripheral veins but also in the portal vein. 6. Mice fasted for 24 hrs displayed a markedly depressed insulin response to tolbutamide injection. Pretreatment of the fasted animals with acid amyloglucosidase could restore the tolbutamide-induced insulin release to the same level as that recorded in a group of freely fed mice. It is suggested that acid amyloglucosidase plays an important role in insulin secretion induced by sulphonylureas. Most evidence suggests that this effect is exerted within the B-cell although an additional effect on the liver cannot be ruled out.     

Global profiling of coxsackievirus- and cytokine-induced gene expression in human pancreatic islets

Aims/hypothesis It is thought that enterovirus infections initiate or facilitate the pathogenetic processes leading to type 1 diabetes. Exposure of cultured human islets to cytolytic enterovirus strains kills beta cells after a protracted period, suggesting a role for secondary virus-induced factors such as cytokines.Methods To clarify the molecular mechanisms involved in virus-induced beta cell destruction, we analysed the global pattern of gene expression in human islets. After 48 h, RNA was extracted from three independent human islet preparations infected with coxsackievirus B5 or exposed to interleukin 1 (50 U/ml) plus interferon (1,000 U/ml), and gene expression profiles were analysed using Affymetrix HG-U133A gene chips, which enable simultaneous analysis of 22,000 probe sets.Results As many as 13,077 genes were detected in control human islets, and 945 and 1293 single genes were found to be modified by exposure to viral infection and the indicated cytokines, respectively. Four hundred and eighty-four genes were similarly modified by the cytokines and viral infection.Conclusions/interpretation The large number of modified genes observed emphasises the complex responses of human islet cells to agents potentially involved in insulitis. Notably, both cytokines and viral infection significantly (p<0.02) increased the expression of several chemokines, the cytokine IL-15 and the intercellular adhesion molecule ICAM-1, which might contribute to the homing and activation of mononuclear cells in the islets during infection and/or an early autoimmune response. The present results provide novel insights into the molecular mechanisms involved in viral- and cytokine-induced human beta cell dysfunction and death.Electronic Supplementary Material Supplementary material is available for this article at .     

Insulin release from human pancreatic islets in vitro

Summary Islets of Langerhans were isolated by collagenase digestion from the pancreas of a 39 year-old female renal transplant donor. The islets were subjected to three consecutive periods of tissue culture, after each of which they were incubated in vitro with various agents whose effects on insulin release from islets of laboratory animals have previously been established. After the first culture period, the basal insulin secretion rate of 5.2 U/islet/h seen with 2 mmol/l glucose was increased approx. 5-fold on raising the glucose concentration to 20 mmol/l. The islets retained the insulin-secretory response to 20 mmol/l glucose throughout the period of study. Insulin secretion was also stimulated by mannose, leucine, -ketoisocaproate, dihydroxyacetone and 3-hydroxybutyrate, but not by fructose or N-acetyl-glucosamine. Fructose however increased insulin release in the presence of 4 mmol/l glucose. Caffeine elicited insulin release in the absence of glucose and enhanced insulin release in response to 10 mmol/l glucose. Glucose-stimulated insulin release was inhibited by trifluoperazine (25 mol/l).     

Alloxan-induced alteration of insulin release,rubidium efflux and glucose metabolism in rat islets stimulated by various secretagogues

Summary Insulin release and⁸⁶Rb efflux were studied in perifused rat islets exposedin vitro to alloxan (2 mmol/l) for 5 min. At a low glucose concentration, alloxan transiently increased⁸⁶Rb efflux. Alloxan immediately and completely abolished the secretory response to glucose (15 mmol/l) and markedly delayed the reduction in⁸⁶Rb efflux normally produced by the sugar. 3-O-methylglucose (20 mmol/l) provided complete protection against the alteration of⁸⁶Rb efflux and partial protection against the inhibition of insulin release. Immediately after alloxan treatment, glyceraldehyde,-ketoisocaproic acid and tolbutamide still induced a rapid release of insulin, but the late phase normally stimulated by glyceraldehyde and-ketoisocaproic acid was inhibited. If islets were exposed to glyceraldehyde or tolbutamide 15 min after alloxan treatment, the rapid insulin release was also markedly impaired. Alloxan failed, however, to affect the ability of these three stimuli to reduce⁸⁶Rb efflux from islet cells. Glucose oxidation and utilization were decreased in alloxan-treated islets and 3-O-methylglucose protected against this effect. The results show that the glucose recognition system in B-cells is the most rapidly and severely affected by alloxan. The drug also alters the response to other secretagogues, the insulin releasing properties of which can be impaired without alteration of their ability to reduce⁸⁶Rb efflux.     

Effect of starvation upon insulin secretion in the rabbit

Summary Plasma insulin and blood glucose levels of normal and fasting rabbits have been studied. The mean plasma insulin of pre-starvation controls was 24 µU/ml; blood glucose was 107 mg/100 ml. After starvation, the insulin levels in the blood decreased to 8 µU/ml and glucose concentration to a mean level of 76 mg/100 ml. The fine structure of - and -cells was studied in fasted animals. Most of the -cells were filled with granules of the pale type and some of these secretory granules were adjacent to the plasmatic membrane, which frequently showed projecting microvilli. Immunoassay figures for pancreatic insulin were obtained. There was a good correlation between the insulin assay results in pancreas on one hand, and light and electron microscopic -cells on the other, provided the assumption is true that pale granules contain immunologically active insulin. Most of the -cells were well granulated, but a few of these cells showed a marked increase in the lamellar ergastoplasm.This work has been supported by a grant from the Seguridad Social del Estado, Madrid.     

Short-term inhibition of peroxisome proliferator-activated receptor-γ coactivator-1α expression reverses diet-induced diabetes mellitus and hepatic steatosis in mice

Aims/hypothesis The coactivator of nuclear receptors, peroxisome proliferator-activated receptor- coactivator-1 (PGC-1) has been implicated in a series of events that contribute to the control of glucose metabolism. We have recently reported the use of a PGC-1 antisense oligonucleotide (PGC-1AS) that inhibits up to 60% of PGC-1 expression in pancreatic islets, leading to increased insulin secretion. This oligonucleotide was used in this study to try to ameliorate diet-induced type 2 diabetes in a genetically predisposed mouse strain (Swiss mice).Materials and methods Glucose and insulin tolerance tests, euglycaemic–hyperinsulinaemic clamp, immunoprecipitation assays, immunoblotting assays and immunohistochemistry were used in this investigation.Results Swiss mice became obese and overtly diabetic after 8 weeks of feeding with chow containing 24% saturated fat. One daily dose (1.0 nmol) of PGC-1AS significantly reduced glucose and increased insulin blood levels without affecting food intake and body weight. These effects were accompanied by a reduced area under the glucose curve during an intraperitoneal glucose tolerance test, an increased constant of glucose decay (K_itt) during an insulin tolerance test, and an increased glucose consumption rate during a euglycaemic–hyperinsulinaemic clamp. Moreover, mice treated with PGC-1AS presented an outstanding reduction of macroscopic and microscopic features of hepatic steatosis. These effects were accompanied by reduced expression or function of a series of proteins involved in lipogenesis.Conclusions/interpretation PGC-1 is an attractive target for pharmacological therapeutics in type 2 diabetes mellitus and diet-induced hepatic steatosis.     

Family study and frequency of blood group with strong B transferase accompanied by decreased A and H antigens

Summary Subgroups of type A blood, named A₁, A₂ and A₁–A₂ intermediate (A_int), are specifically characterized by their peculiar A alleles and have their own A₁-, A₂- or A_int-forms of -N-acetyl-D-galactosaminyltransferase (A-transferase). It is known, however, that certain type A₂B persons exhibit A₁-transferase. The reason may be an unusual -galactosyltransferase (B-transferase). This strong B-transferase competes with A-transferase for the substrate, H antigen, so as to decrease the A and H antigens on the red cells. We studied this blood group over three generations and found that the strong B-transferase is, in fact, inherited with the B gene and is dominant over normal B-transferase. In AB blood groups in Tokyo, the frequency of people with a strong B-transferase is 5% for A₁B and 22% for A₂B. This enzyme does not always cause weak H or A antigens.     

Involvement of α2-Adrenoceptors in mechanism of intragastric nicotine protection against ethanol injury in rat stomach

To elucidate the role of - and -adrenoceptors in the mechanism of intragastric nicotine protection against ethanol-induced gastric mucosal injury, the following studies were performed. At 0.5-hr prior to the injury study, rats were pretreated with: subcutaneous control, prazosin (0.5 mg/kg) or yohimbine (5 mg/kg) to block ₁- or ₂-adrenoceptors; or intraperitoneal control, metoprolol (2 mg/kg) or butoxamine (4 mg/kg) to block ₁- or ₂-adrenoceptors, respectively. At 1-hr intervals, rats received intragastric vehicle or nicotine (4 mg/kg) and 40% ethanol (10 ml/kg). Total lengths of the linear gastric corpus mucosal lesions were measured by an unbiased observer using a caliper. In a separate study, 0.5-hr after subcutaneous control or yohimbine (5 mg/kg), rats were treated with intragastric vehicle or nicotine (4 mg/kg). One hour later, gastric mucus volume, gastric juice volume and pH, and titratable acid in the gastric juice were measured. In the rat stomach, the intragastric nicotine protection against 40% ethanol-induced mucosal injury was not blocked by selective ₁-(prazosin), ₁-(metoprolol), or ₂-(butoxamine) adrenoceptor antagonists. The protection was significantly reduced although not completely abolished by selective ₂-(yohimbine) adrenoceptor antagonist. Yohimbine also significantly reduced basal and nicotine-stimulated increase in gastric mucus volume. These data suggest that ₂-adrenoceptors are involved in the protective effect of intragastric nicotine against 40% ethanol-induced gastric mucosal injury possibly by a mucus-dependent mechanism.Supported by Veternas Administration Medical Research Funds, and in part by research grants (0162-01, 02, and 291-01) from the Smokeless Tobacco Research Council, Inc., and by funds (1RT 80) provided by the Cigarette and Tobacco Surtax Fund of the State of California through the Tobacco-Related Disease Research Program of the University of California to F.W.L. Dr. Endoh is a recipient of the University of California Tobacco-Related Disease Research Program Research Fellowship Award (FT 37).     

Acute hematologic effects of interferon alpha,interferon gamma,tumor necrosis factor alpha and Interleukin 2

Summary This study was designed to investigate acute effects of various doses of the cytokines IFN-alpha, IFN-gamma Interleukin 2 and tumor necrosis factor alpha on white blood cell differential counts. Before initiation of phase II trials, a dose-determination phase was performed, where three different dose levels of each cytokine were applied as a single dose. White blood cell differential counts were assessed immediately before and 2, 12, 24, 48 and 168 h after injection. Patients enrolled suffered from metastatic cancer or chronic active hepatitis. In addition, IFN-alpha was administered to five healthy volunteers. Results indicate that cytokines cause rapid and transient changes in the numbers of leukocyte subsets. Hematologic changes were cell-type- and cytokine-specific: transient lymphopenia was observed after administration of all four cytokines, reaching a nadir 12 to 24 h after subcutaneous injection. Administration of TNF-alpha and IFN-gamma also caused transient monocytopenia. Neutrophilia developed after administration of Interleukin 2, IFN-alpha and TNF-alpha. We conclude that cytokines play a key role in the regulation of peripheral blood cell traffic by their capacity to influence homing patterns of peripheral blood leukocytes.     

Presence of interferon and anti-interferon in patients with systemic lupus erythematosus

Summary Sera from 61 patients with systemic lupus erythematosus (SLE) were serially screened over a period of at least 2 years for IFN and anti-IFN antibodies. IFN concentrations were measured both with a cytopathic effect assay and a more sensitive radioimmunoassay. Of the patients 15% (9/61) had IFN in their serum at one or more occasions as measured in the bioassay (6 IU/ml); employing a RIA (1 IU/ml) 28% (17/61) of the patients studied were positive for IFN-. Fifteen patients had a measurable interferonemia over 2–16 months; only two patients had detectable IFN in their serum at only one occasion. In five patients, hourly and daily variations of the IFN titer as measured by RIA were found to amount to less than 80%. The IFN activity found in these sera was characterized as IFN- by means of acid stability, cross-reactivity on heterologous cells, trypsin sensitivity, and neutralization by homologous and heterologous antisera. IFN antibodies were quantified with a neutralization bioassay, an ELISA, and a radioimmunoassay. Of the 61 patients 5% (3) possessed high titers of anti-IFN antibodies which persisted over 2 years. The IFN- antibody positive patients had an inactive form of the disease over years without visceral involvement but decreased serum complement levels (C4, C3, CH50) and repeated episodes of Quincke-like edema.     

Effect of α2-adrenoceptor antagonist on platelet activation during insulin-induced hypoglycaemia in Type 2 (non-insulin-dependent) diabetes mellitus

Summary The role of epinephrine in platelet activation and the effect of an ₂-adrenoceptor antagonist, midaglizole, during insulin-induced hypoglycaemia in Type 2 (noninsulin-dependent) diabetes mellitus were examined. The action of midaglizole as a platelet ₂-antagonist was confirmed by in vitro studies using platelet-rich plasma and washed platelet suspension. Hypoglycaemia was induced by a bolus injection of short-acting insulin in 24 diabetic patients. They were divided into two groups, a control group (n=12) and an ₂-group (n=12), and midaglizole was administered orally 60 min before insulin injection in the latter. Blood glucose and plasma C-peptide levels were significantly decreased (p<0.005) by insulin injection in both groups. Counter-regulatory hormones, including epinephrine, and arginine vasopressin were similarly increased at the hypoglycaemic nadir compared with the levels at 0 min in both groups. Plasma -thromboglobulin was increased at the hypoglycaemic nadir (165.5±12.6ng/ml) compared with the level at 0 min (121.0±11.5, p<0.005) in the control group, whereas no significant increase was demonstrated in the ₂ group. These results suggest that plasma epinephrine plays an important role in platelet activation during hypoglycaemia in Type 2 diabetes mellitus, and that the platelet activation is prevented by ₂-adrenoceptor antagonist.     

Lazy leukocyte syndrome

Summary A-35-year-old woman with a long-lasting history of neutropenia and recurrent infections was found to have defective neutrophil chemotaxis, random motility, and in vivo migration. Although the bone marrow granulocyte reserve was normal, the patient failed to release an appropriate amount of granulocytes after injection of etiocholanolone. These features are characteristic of the so-called Lazy leukocyte syndrome. The clinical presentation of the five cases of this syndrome so far reported and its pathophysiological aspects are discussed.     

Effects of glucocorticoids and insulin on 3′,5′-AMP phosphodiesterase activity in adrenalectomized rats

Summary Glucocorticoids stimulate the rate of lipolysis which is reduced in adrenalectomized animals. This hormonal action is antagonized by insulin. The antilipolytic action of insulin appears to be mediated by a reduced intracellular concentration of 3,5-AMP. This reduction can partly be attributed to an insulin-induced acceleration of 3,5-AMP degradation. — It is shown that the stimulatory influence of glucocorticoids on lipolysis is due to a reduction of 3,5-AMP phosphodiesterase (PDE) activity, which is increased by adrenalectomy. PDE activity was also increased in liver, skeletal muscle and kidney of adrenalectomized rats; treatment with a glucoeorticoid prevented this increase.In vitro, PDE purified from beef heart was inhibited by glucocorticoids in high concentrations (K_i=1.1 · 10^–3 M for 6 -methylprednisolone hemisuccinate,K _i=1.6 · 10^–3 M for prednisolone succinate).In vivo, the glucocorticoid-induced decrease of PDE activity (with retarded onset as shown in liver), may essentially be attributed to a decreased enzyme synthesis. — Studies on the interaction of insulin and glucocorticoids on PDE activity were performed in the liver. In adrenalectomized, alloxan diabetic rats insulin stimulated PDE activity suppressed by treatment with a glucoeorticoid, unsuppressed PDE activity was not increased by insulin. In contrast, the action of glucocorticoids on PDE activity was independent of the presence or the effectiveness of insulin.

---

Wirkungen von Olucocorticoiden und Insulin auf die 3,5-AMP-Phosphodiesterase-Aktivität bei adrenalektomierten Tieren

Zusammenfassung Die Lipolyse, die bei adrenalektomierten Tieren vermindert ist, wird durch Glucocorticoide verstärkt. Die gegenüber Glucocorticoiden antagonistische Wirkung von Insulin, das die Lipolyse vermindert, kann durch eine Abnahme der intracellulären 3,5-AMP-Konzentration erklärt werden. Diese ist teilweise auf einen beschleunigten Abbau des Nucleotids zurückzuführen. — Die Lipolysesteigerung durch Glucocorticoide ist durch eine Verminderung der 3,5-AMP-Phosphodiesterase (PDE)-Aktivität bedingt, die bei adrenalektomierten Ratten erhöht ist. Die PDE-Aktivität adrenalektomierter Tiere ist auch in Leber, Skeletmuskulatur und Niere erhöht, die Gabe eines Glucocorticoids verhindert diesen Anstieg. Glucocorticoide hemmen aus Rinderherz isolierte PDEin vitro, jedoch sind hohe Steroidkonzentrationen erforderlich (K _i=1.1 · 10^–3 M für 6 -Methylprednisolon-Hemisuceinat, (K _i=1,6 · 10^–3 M für Prednisolon-Succinat). Die einige Stunden nach Gabe eines Glucocorticoids einsetzende Abnahme der PDE-Aktivität kann im wesentlichen auf eine verminderte Enzymsynthese zurückgeführt werden. — Insulin steigert bei adrenalektomierten, alloxandiabetischen Ratten die PDE-Aktivität in der Leber nur, wenn die Tiere mit einem Glucocorticoid behandelt sind, nicht jedoch die erhöhte PDE-Aktivität bei Fehlen von Glucocorticoiden. Der Einfluß von Glucocorticoiden auf die PDE-Aktivität ist dagegen nicht an die Wirkung von Insulin gebunden.

---

Effets des glucocorticoïdes et de l'insuline sur l'activité de la 35-AMP-phosphodiestérase chez des rats surrénalectomisés

Résumé Les glucocorticoïdes stimulent la lipolyse qui est réduite chez les animaux surrénalectomisés. Cette action hormonale est contrecarrée par l'insuline. L'action antilipolytique de l'insuline semble être due à une réduction de la concentration intracellulaire de 35-AMP. Cette réduction peut être attribuée en partie à une accélération due à l'insuline de la dégradation du 35-AMP. On a montré que l'influence stimulatrice des glucocorticoïdes sur la lipolyse est due à une réduction de l'activité de la 35-AMP-phosphodiesterase (PDE), qui est accrue par la surrénalectomie. L'activité de la phosphodiesterase est également augmentée dans le foie, le muscle strié et les reins des rats surrénalectomisés, le traitement par un glucocorticoïde prévient cette augmentation.In vitro, la phosphodiesterase purifiée du coeur de boeuf est inhibée par les glucocorticoïdes à fortes concentrations (K _i=1.1 · 10^–3 M pour l'hémisuccinate de 6 -méthylprednisolone, (K _i=1.6 · 10^–3 M pour le succinate de prednisolone).In vivo, la diminution provoquée par les glucocorticoïdes de l'activité de la phosphodiesterase qui se produit au bout de quelque temps, comme on l'a montré dans le foie, peut essentiellement être attribuée à une synthèse diminuée de l'enzyme. Des études sur l'interaction de l'insuline et des glucocorticoïdes sur l'activité de la phosphodiesterase ont été effectuées sur le foie. Chez les rats surrénalectomisés, rendus diabétiques par l'alloxane, l'insuline stimule l'activité de la phosphodiesterase qui a été supprimée par un traitement avec un glucocorticoïde, l'activité de la phosphodiesterase qui n'a pas été supprimée n'est pas augmentée par l'insuline. Par contre, l'action des glucocorticoïdes sur l'activité de la phosphodiesterase est indépendante de l'action de l'insuline.

---

Non-Standard Abbreviations G 6 P Glucose-6-phosphate - FFA non-esterified, free fatty acids - 3,5-AMP cyclic adenosine-3,5-monophosphate - PDE 3,5-AMP phosphodiesterase This study was supported by the Deutsche Forschungsgemeinschaft.Deceased October 31, 1967.     

Local and Systemic Liberation of Proinflammatory Cytokines in Ulcerative Colitis

Determination of plasma and tissue cytokinelevels in inflammatory bowel disease have frequentlyresulted in conflicting data. In the present study wedetermined in patients with ulcerative colitis (UC), the levels of the proinflammatory cytokinesinterleukin (IL)-1, IL-6, interferon(IFN)-, and tumor-necrosis factor (TNF)-liberated by peripheral blood mononuclear cells (PBMC)and lamina propria mononuclear cells (LPMC) after 48-hrculture with pokeweed mitogen (PWM). IL-1, IL-6,IFN- and TNF- in the supernatant weredetected by ELISA. Results show low basal levels ofIL-1 secretion by PBMC and LPMC, and a considerableincrease after mitogen stimulation. Basal IL-6production by PBMC was higher in UC patients than incontrols [2029 pg/ml, CI₉ (–165 to4223) vs 572 pg/ml (–383 to 1527) respectively, P = 0.05] and also afterPWM activation [14,995 pg/ml (7759 -22230) vs 6598 pg/ml(3240-9956), respectively, P = 0.05]. In LPMC, nodifferences in IL-6 secretion were observed. TNF- in activated PBMC of patients with UC was notsignificantly increased in relation to control (P =0.09). No constitutive secretion of IFN- wasobserved in mononuclear cells. IFN- levelssecreted by activated LPMC were lower in patients withUC than in controls [1571 pg/ml (–108 to 3251) vs7953 pg/ml (3851-12,055), respectively, P = 0.03]. Theseresults suggest that IL-6, IL-1, and TNF- participate as mediators in the inflammatoryphenomena observed in UC. Further studies are necessaryto evaluate the role of IFN- in thiscondition.     

Insulin sensitivity,insulin secretion and glucose effectiveness in diabetic and non-diabetic cirrhotic patients

Summary In cirrhotic patients with normal fasting glucose levels both insulin insensitivity and a blunted early insulin response to oral glucose are important determinants of the degree of intolerance to oral glucose. It is not known whether the ability of hyperglycaemia per se to enhance glucose disposal (glucose effectiveness) is also impaired. It is also unclear whether overt diabetes is due to (1) more marked insulin insensitivity; (2) impaired insulin secretion; (3) reduced glucose effectiveness; or (4) a combination of these mechanisms. We used the minimal model to analyse the results of a 3-h intravenous glucose tolerance test to assess glucose effectiveness, insulin sensitivity and insulin responses in 12 non-diabetic cirrhotic patients, 8 diabetic cirrhotic patients and 10 normal control subjects. Fasting blood glucose levels were 4.8±0.2, 7.5±0.6 and 4.7±0.1 mmol/l, respectively. Fasting insulin and C-peptide levels were higher in both cirrhotic patient groups compared with control subjects. The glucose clearance between 6 and 19 min after i.v. glucose was lower in both cirrhotic groups (non-diabetic, 1.56±0.14, diabetic, 0.76±0.06, control subjects, 2.49±0.16 min^–1%, both p<0.001 vs control subjects). Serum insulin peaked at 3 and 23 min in the non-diabetic cirrhotic patients and control subjects; both peaks were higher in the non-diabetic cirrhotic patients and showed a delayed return to basal levels. In the diabetic cirrhotic patients, the first phase insulin and C-peptide response to i.v. glucose was absent; their early (22–27 min) incremental insulin response to i. v. tolbutamide was however similar to that of control subjects but 43% lower than in the non-diabetic cirrhotic patients (p<0.05). Insulin sensitivity was markedly reduced in both cirrhotic groups (non-diabetic, 1.11±0.24×10^–4, diabetic, 0.33±0.53×10^–4, control subjects, 4.37±0.53×10^–4 min^–1 per mU·l^–1, both p<0.001 vs controls). Glucose effectiveness was normal in the non-diabetic cirrhotic patients but 29% lower in the diabetic group. It would appear that overt diabetes develops in those cirrhotic patients who in addition to insulin insensitivity have a marked impairment of insulin secretion. An associated reduction in glucose effectiveness may be a contributory factor.     

TCR1+ large granular lymphocyte proliferation in rheumatoid arthritis

The T-lymphoproliferative syndrome is characterized by a proliferation of large granular lymphocytes (LGL). It is often associated with neutropenia, and in 30% of cases with rheumatoid arthritis (RA). Phenotypic analysis has demonstrated that in most cases of RA with T-proliferative disease, the LGL represent T cells with a clonal rearrangement of the / T cell receptor (TCR2). Here, three patients with / TCR1⁺ LGL proliferation suffering from long-standing arthritis and neutropenia are described. The first patient with RA showed an expansion of a heterogeneous CD2⁺ CD16⁺ CD56^- LGL population, of which 30% coexpressed TCR1 with V1 rearrangement. The second patient with ankylosing spondylitis and RA was suffering from proliferation of TCR1⁺ (V9^-, V1^-), CD2⁺ CD16^- CD56^- LGL with low coexpression of CD8. The third patient with RA was suffering from a proliferation of TCR1⁺ (V1⁺, V9^-) CD4^- CE8^- CD16^- CD56^- lymphocytes. On the basis of these unusual findings, the pathogenetic role of TCR1⁺ T cells in RA is discussed.     

Expression and secretion of alpha1-proteinase inhibitor are regulated by proinflammatory cytokines in human pancreatic islet cells

Aims/hypothesis Alpha1-proteinase inhibitor (1-PI) has been considered a key player in inflammatory processes. In humans, the main production site of 1-PI is the liver, but other tissues, including pancreatic islets, also synthesise this molecule. The aims of this study were to assess the islet cell types that produce 1-PI, to determine whether 1-PI is actually secreted by islet cells, and to assess how its production and/or secretion are regulated.Methods Expression of 1-PI in human islet cells was assessed by immunofluorescence, electron microscopy and western blotting. Release of 1-PI was analysed by reverse haemolytic plaque assay and ELISA. The effects of cytokines on 1-PI synthesis and secretion were tested.Results Immunofluorescence showed that alpha and delta cells do express 1-PI, whereas beta cells do not. By electron microscopy, we demonstrated a colocalisation of 1-PI with glucagon and somatostatin within secretory granules. Immunolabelling also revealed localisation of 1-PI within the Golgi apparatus, related vesicles and lysosomal structures. The expression of 1-PI in islet cells was also demonstrated by western blotting and ELISA of protein extracts. ELISA and reverse haemolytic plaque assay showed that 1-PI is secreted into the culture medium. Treatment of islet cells with IL-1 and oncostatin M for 4 days increased the production and release of 1-PI.Conclusions/interpretation Our results demonstrate that 1-PI is expressed by the alpha and delta cells of human islets, and that proinflammatory cytokines enhance the production and release of this inhibitor.     

Influence of insulin on cyclic 3′,5′-AMP phosphodiesterase activity in liver,skeletal muscle,adipose tissue,and kidney

Summary Influence of insulin on liver glycogen metabolism and on lipolysis appears to be mediated by a decreased intracellular 3,5-AMP concentration. Reduced formation of 3,5-AMP had been shown in adipose tissue incubated with insulin. The influence of insulin on 3,5-AMP degradation has been investigated. — 3,5-AMP phosphodiesterase (PDE) activity was reduced in liver, adipose tissue and, insignificantly, in skeletal muscle of insulin deficient, i.e. alloxan diabetic or starved rats. I.V. injection of a low dose of insulin (0.5 U/kg) or stimulation of endogenous insulin secretion by injection of glucose led to a rapid increase of PDE activity in these tissues. 15 min after insulin injection liver PDE activity was increased. The maximal effect occurred after 30–45 min. Renal PDE activity was not decreased in alloxan diabetes, insulin injection has been found ineffective. —In vitro, there was an activating effect of crystalline insulin on PDE purified from beef heart. Insulin concentration required for duplication of enzyme activity was of the order of 2 · 10^–5 M. Treatment with actinomycin D nearly prevented stimulation of liver PDE by insulin. This may indicate that the action of insulin on PDE activity is essentially based on an increased enzyme synthesis. — Owing to the influence of insulin secretion on liver and adipose tissue 3,5-AMP concentration, glycogen metabolism and lipolysis can be quickly adapted to food intake.

---

Der Einfluß von Insulin auf die 3,5-AMP-Phosphodiesterase-Aktivität in Leber, Skeletmuskulatur, Fettgewebe und Niere

Zusammenfassung An der Steigerung der Glykogensynthese der Leber und der Verminderung der Lipolyse durch Insulin ist eine Abnahme der 3,5-AMP-Konzentration wesentlich beteiligt. Die 3,5-AMP-Bildung ist in Fettgewebe, das mit Insulin inkubiert wird, vermindert. Insulin beeinflußt jedoch auch den 3,5-AMP-Abbau. -Die 3,5-AMP-Phosphodiesterase (PDE)-Aktivität des Fettgewebes, der Leber und, in geringerem Grade, der Skeletmuskulatur ist im Insulinmangel vermindert, d.h. bei alloxandiabetischen oder hungernden Ratten. I.v. Injektion von 0,5 E/kg Insulin oder eine erhöhte Abgabe von Insulin aus dem Pankreas nach Glucoseinjektion führen in diesen Geweben zu einem raschen Anstieg der PDE-Aktivität. Dieser ist in der Leber schon 15 min nach Insulingabe nachweisbar und erreicht nach 30–45 min sein Maximum. In der Niere ist kein Einfluß von Insulin auf die PDE-Aktivität nachweisbar. — Aus Rinderherz isolierte PDE wirdin vitro durch Insulin aktiviert, jedoch werden2 · 10^–5 M zur Verdopplung der Aktivität benötigt. Actinomycin D verhindert die Steigerung der Leber-PDE-Aktivität nach Insulininjektion. So kann die Wirkung des Hormons im wesentlichen auf eine gesteigerte PDE-Synthese zurückgeführt werden. — Durch diesen Einfluß der Insulininkretion auf die 3,5-AMP-Konzentration in Leber und Fettgewebe können Glykogenstoffwechsel und Lipolyse rasch an die Nahrungsaufnahme angepaßt werden.

---

Influence de l'insuline sur l'activité de la 3,5-AMP-phosphodiestérase dans le foie, le muscle strié, le tissu adipeux et le rein

Résumé L'influence de l'insuline sur le métabolisme du glycogène hépatique et sur la lipolyse semble s'exercer par l'intermédiaire d'une diminution de la concentration de 3,5-AMP intracellulaire. Onamontré une diminution de la formation de 35-AMP dans le tissu adipeux incubé avec de l'insuline. L'influence de l'insuline sur la dégradation du 3,5-AMP est étudiée. — L'activité de la 3,5-AMP-phos-phodiestérase (PDE) est diminuée dans le foie, le tissu adipeux et, de façon non-significative, dans le muscle strié des rats qui manquent d'insuline, c-à-d les rats rendus diabétiques par l'alloxane ou les rats privés de nourriture. L'injection intraveineuse d'une faible dose d'insuline (0.5 U/kg) ou la stimulation de la sécrétion d'insuline endogène par une injection de glucose provoquent une augmentation rapide de l'activité de la phosphodiestérase dans ces tissus. 15 min après l'injection d'insuline, l'activité de la phosphodiesterase du foie est augmentée. L'effet maximum est atteint après 30–45 min. L'activité de la phosphodiestérase rénale n'est pas diminuée dans le diabète alloxanique, l'injection d'insuline s'est avérée inefficace.In vitro, l'insuline cristalline a un effet activant sur la phosphodiestérase purifiée du coeur de boeuf. La concentration d'insuline requise pour doubler l'activité de l'enzyme est de l'ordre de 2 · 10^–5 M. Le traitement avec actinomycin D empêche la stimulation par l'insuline de la PDE dans le foie. Ceci peut indiquer que l'action de l'insuline sur l'activité de la phosphodiestérase est essentiellement basée sur une synthèse accrue de l'enzyme. A cause de l'influence de la sécrétion d'insuline sur la concentration en 3,5-AMP du foie et du tissu adipeux, le métabolisme du glycogène et la lipolyse peuvent s'adapter rapidement à la prise de nourriture.

---

Non-Standard Abbreviations G 6 P Glucose-6-phosphate - UDPG UDP-glucose - FFA non-esterifled, free fatty acids - 3,5-AMP cyclic adenosine-3,5-monophosphate - PDE 3,5-AMP phosphodiesterase This study was supported by the Deutsche Forschungsgemeinschaft.Deceased October 31, 1967.     

Triplication (/ααα<Superscript>Anti3.7</Superscript>) or deletion (-α<Superscript>3.7</Superscript>/) association in Argentinian β-thalassemic carriers

Prevalence of alpha gene triplication or deletion in -thalassemia carriers was studied in 109 unrelated individuals in Rosario, Argentina. In different populations -^3.7 allele presents a higher prevalence than ^anti3.7; thus, -thalassemia associated with -thalassemia is more frequently observed. Nevertheless, this event was detected in only one case (0.9%), while the association with alpha triplication was present in two subjects (1.8%).     

Enhanced Expression of Transforming Growth Factor (TGF) -α Precursor and TGF-β1 During Paneth Cell Regeneration

An intravenous injection of diphenylthiocarbazone (dithizone), a zinc chelator, induces selective killing and rapid regeneration of Paneth cells, which have a large amount of zinc in their cytoplasmic granules. We examined the expression pattern of transforming growth factor (TGF) - and TGF-₁ in this regenerative process. Messenger RNA expression of TGF- and TGF-₁ reached their peaks at 12 and 24 hr after dithizone injection, respectively. Protein expression of TGF- precursor and TGF-₁ increased to a maximum at 24 and 72 hr, respectively. Their immunoreactivities were localized in the epithelial cells in the vicinity of Paneth cells, whereas they were prominent in the upper half of the crypts in control rats. In conclusion, destruction of Paneth cells induced TGF- precursor expression, followed by an increase of TGF-₁ especially in the crypt bases. This unique expression pattern of two growth factors may be involved in rapid regeneration of Paneth cells.