Metformin suppresses hepatic gluconeogenesis and lowers fasting blood glucose levels through reactive nitrogen species in mice.

AIMS/HYPOTHESIS: Metformin, the major target of which is liver, is commonly used to treat type 2 diabetes. Although metformin activates AMP-activated protein kinase (AMPK) in hepatocytes, the mechanism of activation is still not well known. To investigate AMPK activation by metformin in liver, we examined the role of reactive nitrogen species (RNS) in suppression of hepatic gluconeogenesis. METHODS: To determine RNS, we performed fluorescence examination and immunocytochemical staining in mouse hepatocytes. Since metformin is a mild mitochondrial complex I inhibitor, we compared its effects on suppression of gluconeogenesis, AMPK activation and generation of the RNS peroxynitrite (ONOO(-)) with those of rotenone, a representative complex I inhibitor. To determine whether endogenous nitric oxide production is required for ONOO(-) generation and metformin action, we used mice lacking endothelial nitric oxide synthase (eNOS). RESULTS: Metformin and rotenone significantly decreased gluconeogenesis and increased phosphorylation of AMPK in wild-type mouse hepatocytes. However, unlike rotenone, metformin did not increase the AMP/ATP ratio. It did, however, increase ONOO(-) generation, whereas rotenone did not. Exposure of eNOS-deficient hepatocytes to metformin did not suppress gluconeogenesis, activate AMPK or increase ONOO(-) generation. Furthermore, metformin lowered fasting blood glucose levels in wild-type diabetic mice, but not in eNOS-deficient diabetic mice. CONCLUSIONS/INTERPRETATION: Activation of AMPK by metformin is dependent on ONOO(-). For metformin action in liver, intra-hepatocellular eNOS is required.

Exendin-4 protects pancreatic beta cells from the cytotoxic effect of rapamycin by inhibiting JNK and p38 phosphorylation.

It has been reported that the immunosuppressant rapamycin decreases the viability of pancreatic beta cells. In contrast, exendin-4, an analogue of glucagon-like peptide-1, has been found to inhibit beta cell death and to increase beta cell mass. We investigated the effects of exendin-4 on the cytotoxic effect of rapamycin in beta cells. Incubation with 10 nM rapamycin induced cell death in 12 h in murine beta cell line MIN6 cells and Wistar rat islets, but not when coincubated with 10 nM exendin-4. Rapamycin was found to increase phosphorylation of c-Jun amino-terminal kinase (JNK) and p38 in 30 minutes in MIN6 cells and Wistar rat islets while exendin-4 decreased their phosphorylation. Akt and extracellular signal-regulated kinase (ERK) were not involved in the cytoprotective effect of exendin-4. These results indicate that exendin-4 may exert its protective effect against rapamycin-induced cell death in pancreatic beta cells by inhibiting JNK and p38 signaling.

Src activation generates reactive oxygen species and impairs metabolism-secretion coupling in diabetic Goto-Kakizaki and ouabain-treated rat pancreatic islets.

AIMS/HYPOTHESIS: Na(+)/K(+)-ATPase inhibition by ouabain suppresses ATP production by generating reactive oxygen species (ROS) and impairs glucose-induced insulin secretion from pancreatic islets. To clarify the signal-transducing function of Na(+)/K(+)-ATPase in decreasing ATP production by the generation of ROS in pancreatic islets, the involvement of Src was examined. In addition, the significance of Src activation in diabetic islets was examined. METHODS: Isolated islets from Wistar rats and diabetic Goto-Kakizaki (GK) rats (a model for diabetes) were used. ROS was measured by 5-(and 6)-chloromethyl-2',7'-dichlorofluorescein fluorescence using dispersed islet cells. After lysates were immunoprecipitated by anti-Src antibody, immunoblotting was performed. RESULTS: Ouabain caused a rapid Tyr(418) phosphorylation, indicating activation of Src in the presence of high glucose. The specific Src inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2) restored the ouabain-induced decrease in ATP content and the increase in ROS production. Both PP2 and ROS scavenger restored the impaired insulin release and impaired ATP elevation in GK islets, but had no such effect in control islets. PP2 reduced the high glucose-induced increase in ROS generation in GK islet cells but had no effect on that in control islet cells. Moreover, ouabain had no effect on ATP content and ROS production in the presence of high glucose in GK islets. CONCLUSIONS/INTERPRETATION: These results indicate that Src plays a role in the signal-transducing function of Na(+)/K(+)-ATPase, in which ROS generation decreases ATP production in control islets. Moreover, ROS generated by Src activation plays an important role in impaired glucose-induced insulin secretion in GK islets, in which Src is endogenously activated independently of ouabain.

Pathology of early- vs late-onset TTR Met30 familial amyloid polyneuropathy.

BACKGROUND: Late-onset type I familial amyloid polyneuropathy (FAP TTR Met30) cases unrelated to endemic foci in Japan show clinical features setting them apart from early-onset cases in endemic foci. OBJECTIVE: To compare pathologic features between the early- and late-onset types. METHODS: Pathologic findings in FAP TTR Met30 with onset before age 50 in relation to endemic foci (11 cases) were compared with those in 11 later-onset cases unrelated to endemic foci. RESULTS: Sural nerve biopsy specimens showed predominantly small-fiber loss in early-onset cases; variable fiber size distribution, axonal sprouting, and relatively preserved unmyelinated fibers characterized late-onset cases. Autopsy cases representing both groups showed amyloid deposition throughout the length of nerves and in sympathetic and sensory ganglia, but amounts were greater in early-onset cases. Amyloid deposition and neuronal cell loss were greater in sympathetic than dorsal root ganglia in early-onset cases; the opposite was true in late-onset cases. Size assessment of remaining neurons in these ganglia suggested predominant loss of small neurons in early-onset cases but loss of neurons of all sizes in late-onset cases. Transthyretin-positive, Congo red-negative amorphous material was more conspicuous in nerves from late- than early-onset cases. In extraneural sites, amyloid was more conspicuous in thyroid and kidney from early-onset cases and in heart and hypophysis from late-onset cases. In early-onset cases, cardiac amyloid deposition was prominent in the atrium and subendocardium but was conspicuous throughout the myocardium in late-onset cases. CONCLUSION: The pathology of early- and late-onset FAP TTR Met30 correlated well with differences in clinical findings.

Normalization of cytoplasmic calcium response in pancreatic beta-cells of spontaneously diabetic GK rat by the treatment with T-1095, a specific inhibitor of renal Na+-glucose co-transporters.

Chronic hyperglycemia is known to lead to a progressively further impaired insulin response and to hasten the development of complications in patients with type 2 diabetes, a notion referred as glucose toxicity. T-1095, a derivative of phlorizin, is a newly developed oral hypoglycemic agent that acts as a specific inhibitor of renal Na(+)-glucose co-transporters, reducing circulating blood glucose levels by promoting glucose excretion into urine. The effects of glycemic improvement by T-1095 on secretory function and cytoplasmic calcium response in pancreatic beta-cells were investigated using spontaneously diabetic GK rats. After four weeks of treatment with T-1095 (age 4 to 8 week rats), serum glucose and HbA1c levels were significantly improved (serum glucose level, GK vs. GK T-1095, 277.3 +/- 11.8 vs. 204.7 +/- 6.4 mg/dl; HbA1c level, GK vs. GK T-1095, 6.2 +/- 0.2 vs. 4.8 +/- 0.1 %). Insulin secretion induced by 16.7 mM glucose was also significantly increased in the T-1095-treated group compared to the untreated group. The [Ca(2+)]i response induced by 16.7 mM glucose in GK beta-cells was characterized by the loss of the steep first peak of [Ca(2+)]i elevation, and the lost first peak of [Ca(2+)]i reappeared in T-1095-treated beta-cells in 32 of 34 observations. In T-1095-treated beta-cells, the time lag to peak [Ca(2+)]i levels in the 16.7 mM glucose stimulation was significantly reduced (259.1 +/- 15.3 sec, p < 0.01) compared to untreated GK rats (524.7 +/- 52.9 sec). Thus, improvement of hyperglycemia by T-1095 ameliorates beta-cell function by relieving [Ca(2+)]i response.

Recovery of function and mass of endogenous beta-cells in streptozotocin-induced diabetic rats treated with islet transplantation.

Islet transplantation corrects chronic hyperglycemia by augmentation of insulin supply from the graft tissue, but the role of endogenous beta-cells after transplantation is not clear. In the present study, we examined endogenous beta-cell function after glucose homeostasis had been reestablished by islet graft in streptozotocin (STZ)-induced diabetic rats. Fed plasma glucose levels in diabetic rats transplanted with a large number of islets (2500 islets) into the left kidney capsule soon became lower (139.8 +/- 8.2 mg/dl) and close to the level in controls (129.7 +/- 11.3 mg/dl), and IPGTT exhibited a pattern of plasma glucose response almost identical to control. The insulin and DNA contents, islet area, and the distribution of beta-cells that were markedly deteriorated in islets of STZ rats were significantly restored in transplanted rats. The insulin release in response to glucose or alpha-ketoisocaproate was less in STZ rats, while in islets of transplanted rats the secretion recovered to levels similar to controls. On the other hand, arginine-induced insulin release was conversely hyperresponsive in STZ rats, but in transplanted rats, the response was decreased similar to controls. Thus, as the plasma glucose level normalizes, residual beta-cells show a recovery of function that cannot be accounted for by the increase in mass alone.

Heat shock restores insulin secretion after injury by nitric oxide by maintaining glucokinase activity in rat islets.

Heat shock protein (hsp), including hsp70, has been reported to restore the glucose-induced insulin release suppressed by nitric oxide (NO). However, the mechanism underlying this recovery remains unclear. In the present study, we examine the effects, in rat islets, of heat shock on insulin secretion inhibited by a small amount of NO and also on glucose metabolism, the crucial factor in insulin release. Exposure to a higher dose (15 U/ml) of interleukin-1beta (IL-1beta) abolished the insulin release by stimulation of glucose or KCl in both control and heat shocked islets. In rat islets exposed to a lower dose (1.5 U/ml) of IL-1beta, insulin secretion in response to glucose, but not to glyceraldehydes (GA), ketoisocaproate (KIC), or KCl, was selectively impaired, concomitantly with lower ATP concentrations in the presence of 16.7 mM glucose, while such suppression of insulin secretion and ATP content was not observed in heat shock-treated islets. NO production in islets exposed to 1.5 U/ml IL-1beta was significantly, but only partly, decreased by heat shock treatment. The glucose utilization rate measurement using [5-3H]-glucose and [2-3H]-glucose and the glucokinase activity in vitro were reduced in islets treated with 1.5 U/ml IL-1beta. In heat shock-treated islets, glucose utilization and glucokinase activity were not affected by 1.5 U/ml IL-1beta. These data suggest that heat shock restores glucose-induced insulin release inhibited by NO by maintaining glucokinase activity and the glucose utilization rate in islets in addition to reducing endogenous NO production.

Distinct effect of diazoxide on insulin secretion stimulated by protein kinase A and protein kinase C in rat pancreatic islets.

Protein kinase activation is known to stimulate glucose-induced insulin secretion in the presence of diazoxide. Diazoxide opens the ATP-sensitive K(+) channel and inhibits FAD-linked glycerophosphate dehydrogenase activity in a concentration-dependent manner. In the present study, we examined the effect of lower (100 microM) and higher (250 microM) concentrations of diazoxide on insulin release by protein kinase A (PKA) and protein kinase C (PKC) activation. Forced depolarization by a high potassium concentration, augmented the intracellular Ca(2+) concentration ([Ca(2+)](i)) similarly in the presence of both concentrations of diazoxide. Under this condition, 250 microM diazoxide inhibited insulin release enhanced by PKA activation but not that by PKC. Under a basal concentration of [Ca(2+)](i), PKC activation elicited glucose-induced insulin secretion at 100 and 250 microM diazoxide, while PKA activation did so only at 100 microM. These augmentations were completely inhibited by mannoheptulose, a glucokinase inhibitor. Glyceraldehyde, in place of glucose, enhanced insulin secretion by PKC activation under both concentrations of diazoxide. On the other hand, it did not affect PKA-stimulated insulin release under either conditions, but in the case of 100 microM, glucose augmented the insulin secretion in the presence of glyceraldehyde and db-cAMP concentration-dependently. These data suggest that insulin release stimulated by PKA and PKC activation under diazoxide is dependent on glucose metabolism, and that a signal derived from proximal steps in glycolysis may be necessary for the secretion by PKA activation.

[Improvement of method to estimate guidance by pharmacists and trial to obtain standard pharmaceutical management and guidance services program].

The level of understanding of taking medicine was examined at the start and the end of medicine-taking guidance, based on the estimation by pharmacists and inpatients. Six items for the estimation, such as "the way of taking medicines" were evaluated using a five-grade system. The significant improvement was observed in all items, suggesting that inpatients' understanding is improved by the guidance. A markedly positive correlation was found between the estimation by inpatients and that by pharmacists (p < 0.001). This confirms the appropriateness of estimation by pharmacists. Inpatients whose estimation was significantly different from that by pharmacists (difference of two grades or more) were examined to identify clear and potential problems with taking medicine. The problems were classified into such seven categories as "types of medicine". For each item with differences in estimation (two grades or more), problems were biased in some specific categories. On the basis of such a bias, a flow chart was prepared to clarify problems. In addition, a standard pharmaceutical management and guidance services program was drafted, in which measures in observation, treatment and education against problems by pharmacists were described according to the frequency of occurrence. Information about the program available on the Internet enables its use by other hospitals.

A novel glucokinase regulator in pancreatic beta cells: precursor of propionyl-CoA carboxylase beta subunit interacts with glucokinase and augments its activity.

A glucokinase regulatory protein has been reported to exist in the liver, which suppresses enzyme activity in a complex with fructose 6-phosphate, whereas no corresponding protein has been found in pancreatic beta cells. To search for such a protein in pancreatic beta cells, we screened for a cDNA library of the HIT-T15 cell line with the cDNA of glucokinase from rat islet by the yeast two hybrid system. We detected a cDNA encoding the precursor of propionyl-CoA carboxylase beta subunit (pbetaPCCase), and glutathione S-transferase pull-down assay illustrated that pbetaPCCase interacted with recombinant rat islet glucokinase and with glucokinase in rat liver and islet extracts. Functional analysis indicated that pbetaPCCase decreased the K(m) value of recombinant islet glucokinase for glucose by 18% and increased V(max) value by 23%. We concluded that pbetaPCCase might be a novel activator of glucokinase in pancreatic beta cells.

Gastrointestinal disorder and Helicobacter pylori infection in patients with rheumatoid arthritis.

Abstract Gastrointestinal disorders such as gastritis and peptic ulceration are very common in patients with rheumatoid arthritis. Helicobacter pylori appeared to be a high risk factor for the development of peptic ulcers or chronic active gastritis. Thus, the objective of this study is to elucidate gastrointestinal findings and the prevalence of H. pylori in patients with rheumatoid arthritis. Consecutive RA patients were recruited for this study, irrespective of gastrointestinal symptoms. Routine endoscopy was performed and mucosal specimens were analyzed according to the Sydney system. H. pylori infection was determined histologically using H-E staining, Wartin Starry silver staining, and immunohistochemistry. Of 97 patients, only 16 had gastrointestinal symptoms. By endoscopic examination, gastritis was observed in 39 patients (40.2%), gastric ulcers in 24 patients (24.7%), and duodenal ulcers in 7 patients (7.2%). The histological results analyzed by the Sydney system showed "inflammation," "active," and "atrophy" for 71.1%, 58.5%, and 54.6% of samples, respectively. Sixty patients (61.9%) were infected by H. pylori, but the presence of H. pylori did not increase the chance of endoscopic gastrointestinal disorders. The presence of a rheumatoid factor was inversely related to H. pylori infection, and the value of the rheumatoid factor was lower in patients with the infection. In conclusion, it was found that H. pylori infection was not a major cause of gastrointestinal disorders in RA, and that the presence of rheumatoid factor significantly reduces the chance of H. pylori infection.

Comparative study of symptoms and neuroendocrine-immune network mediator levels between rheumatoid arthritis patients and healthy subjects.

OBJECTIVE: In order to understand the disturbances in the neurophysiological, endocrine (including the hypothalamic-pituitary-adrenal axis), and immune systems objectively and in detail, we measured and compared various test items in the peripheral blood which were considered to reflect the state of these systems, in patients with rheumatoid arthritis and in control subjects. METHODS: The levels of beta-endorphin, methionine-enkephalin, epinephrin, norepinephrin (NE), dopamine, corticotropin releasing factor (CRF), adrenocoricotropic hormone (ACTH), cortisol, CD4/CD8 ratio, CD57, NK cell activity and IL-6 in the peripheral blood, which are considered to reflect the activity of this neuroendocrine-immune network, were measured and compared between 49 patients with rheumatoid arthritis (RA) and 54 healthy control subjects. The face scale (to measure mood) and the Cornell medical index (CMI) health questionnaire were administered to both groups, and pain scores were measured using a visual analog scale in the RA group. RESULTS: The serum levels of NE, dopamine, IL-6 and CD4/CD8 ratio were higher, whereas the levels of beta-endorphine, ACTH and NK cell activity were lower in the RA subjects than in the control subjects. On the other hand, the serum levels of Met-enk, epinephrin, CRF, cortisol and CD57 were not significantly different between the two groups. In RA patients a positive correlation was observed between the face scale score and the serum cortisol level and between the pain score and the serum IL-6 level. The more severe the pain, the higher the NK cell activity and IL-6 concentrations in the peripheral blood. On the other hand, in healthy females none of the measured items in the peripheral blood were significantly correlated with the face scale results or the responses to the CMI health questionnaire. CONCLUSION: In RA patients the hypothalamic-pituitary-adrenal (HPA) axis is altered and this condition is correlated to a deterioration in symptoms.

[Development and evaluation of a local area network system to make drug information paper for inpatient--adaptation to characteristics of diseases, and expansibility to other hospitals and the Internet].

We developed and evaluated a local area network system to make drug information papers. Because pharmacists should explain drug information both orally and using papers to patients in response to their understanding and characteristics of their diseases. The merit of this system is as follows: pharmacists can use it without any education for its operation; most data can be inputted by selection from the lists and automatic reference; the data are adjustable for individuals; different contents are available for different wards; multiple users can access the same data file. Input data in this system are available for making explanation papers on the medical examination of outpatients, and making a plan for pharmaceutical care and guidance services. This system is also available in other hospitals, and on the internet. First, we surveyed the time required for preparing drug information papers. Making a hand written paper for typical patient takes 395 sec. for manuscript, 160 sec. with the system using text data only, and 178 sec. with the system using text and picture data. Next, we surveyed 27 patients' views on the addition of drug pictures to drug information papers, and with the result that 19 patients thought it very good. Last, we surveyed 13 ward pharmacists about their usage of this system. We found that 8 pharmacists used frequently this system, and 3 pharmacists used the same file in the same hours at the maximum.

Augmentation of basal insulin release from rat islets by preexposure to a high concentration of glucose.

We have found that preexposure to an elevated concentration of glucose reversibly induces an enhancement of basal insulin release from rat pancreatic islets dependent on glucose metabolism. This basal insulin release augmented by priming was not suppressed by reduction of the intracellular ATP or Ca(2+) concentration, because even in the absence of ATP at low Ca(2+), the augmentation was not abolished from primed electrically permeabilized islets. Moreover, it was not inhibited by an alpha-adrenergic antagonist, clonidine. A threshold level of GTP is required to induce these effects, because together with adenine, mycophenolic acid, a cytosolic GTP synthesis inhibitor, completely abolished the enhancement of basal insulin release due to the glucose-induced priming without affecting the glucose-induced increment in ATP content and ATP-to-ADP ratio. In addition, a GDP analog significantly suppressed the enhanced insulin release due to priming from permeabilized islets in the absence of ATP at low Ca(2+), suggesting that the GTP-sensitive site may play a role in the augmentation of basal insulin release due to the glucose-induced priming effect.

[Two families of Charcot-Marie-Tooth disease with Adie's pupil, axonal neuropahy and the Thr124Met mutation in the peripheral myelin protein zero gene].

We reported two families of Charcot-Marie-Tooth disease (CMT) with Thr124Met mutation in the peripheral myelin protein zero (MPZ). The clinical features of the proband patients of both families showed Adie's pupil, severe sensory dominant neuropathy in lower extremities, and axonal changes in sural nerve biopsies and nerve conduction studies. Muscle atrophy and weakness was mild in the lower legs, while sensory impairment was marked. The proband patient of family 1 had four symptomatic siblings and one of them showed Adie's pupil. The elderly daughter of the proband of family 2 showed Adie's pupil and younger daughter showed photophobia. The biopsied sural nerves of both proband patients revealed prominent axonal sprouting, and sub-perineurial edema and mild fascicular enlargement. Segmental demyelination was not frequent in teased fiber assessment. The present two family cases strongly suggest that this MPZ gene mutation (Thr124Met) could be present among the patients with CMT type 2, axonal form. Furthermore, the patients showing sensory neuropathy and Adie's pupil may need to be reexamined with this mutation. It is also necessary to reassess genotype-phenotype correlation in CMT patients particularly in reference to type 1 and type 2.

The insulinotropic mechanism of the novel hypoglycaemic agent JTT-608: direct enhancement of Ca(2+) efficacy and increase of Ca(2+) influx by phosphodiesterase inhibition.

We examined the effects of the novel hypoglycaemic agent JTT-608 [trans-4-(4-methylcyclohexyl)-4-oxobutyric acid] on insulin secretion using rat pancreatic islets, and analysed the mechanism of its effect. JTT-608 augmented 8.3 mM glucose-induced insulin secretion dose-dependently, and there was a stimulatory effect of 100 microM JTT-608 at both moderate and high concentrations (8.3, 11. 1 and 16.7 mM) of glucose, but not at low concentrations (3.3 and 5. 5 mM). In perifusion experiments, both phases of insulin release were enhanced, and the effect was eliminated 10 min after withdrawal of the agent. In the presence of 200 microM diazoxide and a depolarizing concentration (30 mM) of K(+), there was an augmentation of insulin secretion by 100 microM JTT-608, not only under high levels of glucose but also under low levels, and the effects were abolished by 10 microM nitrendipine. JTT-608 augmented insulin secretion from electrically permeabilized islets in the presence of stimulatory concentrations (0.3 and 1.0 microM) of Ca(2+), and the intracellular Ca(2+) concentration ([Ca(2+)](i)) response under 16.7 mM glucose, 200 microM diazoxide, and 30 mM K(+) was also increased. The cyclic AMP content in the islets was increased by 100 microM JTT-608, and an additive effect to 1 microM forskolin was observed, but not to 50 microM 3-isobutyl-1-methylxanthine (IBMX). JTT-608 inhibited phosphodiesterase (PDE) activity dose-dependently. We conclude that JTT-608 augments insulin secretion by enhancing Ca(2+) efficacy and by increasing Ca(2+) influx. This appears to be a result of the increased intracellular cyclic AMP concentration due to PDE inhibition.

[Development and assessment of the pharmaceutical management and guidance services for inpatients considering clinical value and economy].

We developed pharmaceutical management and guidance services for inpatients in a ward of circulatory medicine, considering clinical and economical standpoints. In these services, pharmacists deliver drugs prescribed for inpatients with individual drug information papers, explain to them about their drugs using information papers and give counsel. Since most of the patients were aged people, developing many kinds of diseases and taking many kinds of drugs, they had many problems such as lack of knowledge of the effects of drugs. First, we surveyed views of patients, physicians and nurses on these services. Consequently, all of them advised us that "pharmacists should explain to patients about the prescribed drugs using information papers." The patients preferred pharmacists as expositors of drugs to physicians or nurses. The physicians considered that "pharmacists have to attach importance to clinical information and package-inserts of drugs and explain to patients about drug information using pamphlet in response to the understanding of patients." The nurses wanted to cooperate with pharmacists in "improving medication compliance." On the basis of these views, we improved our services. Next, we made a survey of patients' knowledge about their drugs. We found that in the patients the level of knowledge concerning "ways," "effects" and "reasons" of taking drugs and that of "compliance" and "satisfaction in taking drugs" were improved through these services. The patients reentered in the hospital kept a high level. The ratio of patients taking drugs by themselves increased. Last, we also applied this method to wards of "blood and collagen diseases" and "pediatrics." The demand for these services increased smoothly. We compared these services based on our method with all other services by hospital pharmacists from the viewpoint of economy. We found that only our service method was beneficial.

An insulinotropic effect of vitamin D analog with increasing intracellular Ca2+ concentration in pancreatic beta-cells through nongenomic signal transduction.

The effect of 1alpha,25-dihydroxylumisterol3 (1alpha,25(OH)2lumisterol3) on insulin release from rat pancreatic beta-cells was measured to investigate the nongenomic action of vitamin D via the putative membrane vitamin D receptor (mVDR). 1Alpha,25(OH)2lumisterol3, a specific agonist of mVDR, dose-dependently augmented 16.7 mM glucose-induced insulin release from rat pancreatic islets and increased the intracellular Ca2+ concentration ([Ca2+]i), though not increasing Ca2+ efficacy in the exocytotic system. These effects were completely abolished by an antagonist of mVDR, 1beta,25-dihydroxyvitamin D3 (1beta,25(OH)2D3), or by a blocker of voltage-dependent Ca2+ channels, nitrendipine. Moreover, both [Ca2+]i elevation, caused by membrane depolarization, and sufficient intracellular glucose metabolism are required for the expression of these effects. 1Alpha,25(OH)2lumisterol3, therefore, has a rapid insulinotropic effect, through nongenomic signal transduction via mVDR, that would be dependent on the augmentation of Ca2+ influx through voltage-dependent Ca2+ channels on the plasma membrane, being also linked to metabolic signals derived from glucose in pancreatic beta-cells. However, further investigations will be needed to discuss physiologically the meaning of insulinotropic effects of vitamin D through mVDR.

Nisoldipine improves the impaired erythrocyte deformability correlating with elevated intracellular free calcium-ion concentration and poor glycaemic control in NIDDM.

AIMS: To explore the mechanisms underlying the impaired erythrocyte deformability (RBC-df) in diabetic patients, the relationship between erythrocyte intracellular free calcium-ion concentration ([Ca2+]i) and RBC-df, and the effects of Ca2+-channel blocker on [Ca2+]i and RBC-df were evaluated. METHODS: Forty-eight patients with NIDDM and 24 control subjects were enrolled in this study. [Ca2+]i was determined using fura-2, and RBC-df by filtration method expressed as Deformability Index (DI). Erythrocytes were treated with nisoldipine to evaluate the effects of a Ca2+-channel blocker. RESULTS: [Ca2+]i was significantly higher (82.6 (78.0-87.2) vs 76.6 (74.3-81.2) nmol lRBC-1, P<0.001), and DI was significantly lower (0. 14 (0.09-0.28) vs 0.22 (0.16-0.28), P<0.01) in NIDDM than in controls. There was a significant correlation between HbA1c and [Ca2+]i (r=0.38, P<0.01), between HbA1c and DI (r=-0.51, P<0.01), and between [Ca2+]i and DI (r=-0.42, P<0.01). Stepwise multiple regression analysis revealed HbA1c and [Ca2+]i as independent determinants for the impaired RBC-df. Nisoldipine treatment in vitro significantly decreased [Ca2+]i, and significantly improved RBC-df. CONCLUSIONS: These data indicate that the impaired RBC-df in NIDDM may at least partly be attributed to the elevated [Ca2+]i and poor glycaemic control. In addition, favorable effects of a Ca2+-channel blocker on both [Ca2+]i and RBC-df have been demonstrated.

[A severe case of acute autonomic and sensory neuropathy].

Acute autonomic and sensory neuropathy (AASN) is a rare neuropathy characterized by acute autonomic dysfunction and objective sensory disturbances. A 26-year-old pregnant woman with severe autonomic and sensory dysfunction is reported. This patient suddenly developed marked nausea and vomitting in about 2 days after having a sore throat. She then developed signs of autonomic dysfunction including dilated non-reactive pupils, dryness of the eyes and oral mucous membranes, generalized anhidrosis, paralytic ileus, orthostatic hypotension, and continuous tachycardia. She also had severe generalized sensory impairments of all modalities, and all deep tendon reflexes were absent. Sensation was almost totally lost for all modalities below the neck. There was marked pseudoathetosis and sensory ataxia in all extremities. Motor examination was normal. She had inability to urinate. At this time she was 38 weeks pregnant, and when she showed signs of fetal distress, a Caesarean section was performed. Albumino-cytological dissociation was seen in the CSF. Serum noradrenaline was reduced, no sensory nerve action potentials could be elicited, and reduced coefficient of variation of the R-R interval on electrocardiography was observed. Plasma exchange was performed every other day for 3 days for about 3 weeks after the onset of the illness, but no favorable effects. Seven months after the onset, her autonomic dysfunction slightly improved, but there was no recovery from the sensory disturbances. Many symptoms and signs that characterize AASN occurred in this patient, and each was severe. The patient developed SIADH, sleep apnea, personality change, and amenorrhea in the course of the disease. We suggest that AASN patients might have both peripheral and central nervous system manifestations including seizures and personality changes.