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1.
J Pediatr Endocrinol Metab ; 14 Suppl 1: 589-95, 2001.
Article in English | MEDLINE | ID: mdl-11393549

ABSTRACT

The study group of the Japan Diabetes Society (JDS) carried out nationwide hospital-based and population-based surveys of childhood type 1 diabetes mellitus (DM) in Japan. According to the nationwide population-based survey, the incidence of childhood type 1 DM in Japan was 1.5 (1.4-1.6)/10(5), which did not differ for the 5 years from 1986-1990. Predisposition for DM and autoimmunity were studied in the first-degree relatives of the patients, including older and later cohorts. The prevalence of type 1 DM was 3.3% (12/369) among siblings and 2.2% (8/369) among parents, while the prevalence of type 2 DM was 0% among siblings and 4.3% (16/369) among parents. The risk of type 1 DM among siblings of the patients was 330 times higher than that among the general population in the Japanese population. The rate of positivity for autoantibodies, including ICA, IAA, GAD and IA-2, was 1.4-2.9% in parents (n=140) and 2.0-3.9% in siblings (n=203). The genetic susceptibility for type 1 DM is far lower in Japanese children than in Caucasian children, but predisposition to the disease and positive autoimmunity are almost the same in Japanese families of patients as in Caucasian families. The quality of life of Japanese parents of children with type 1 DM was less satisfactory that that of the Caucasian parents previously reported, which might be a result of the low incidence of type 1 DM in Japan.


Subject(s)
Diabetes Mellitus, Type 1/epidemiology , Diabetes Mellitus, Type 1/genetics , Genetic Predisposition to Disease , Child , Child, Preschool , Female , Humans , Incidence , Infant , Infant, Newborn , Japan , Male , Parents , Quality of Life
2.
Clin Genet ; 59(3): 194-7, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11260230

ABSTRACT

Mutations in the insulin receptor gene have been reported in cases of type A insulin resistance. We report herein two cases of type A insulin resistance, which involve some novel mutations. Case 1 is a heterozygote of the C253Y missense mutation and case 2 is a heterozygote of the Y864X nonsense mutation. In the C253Y missense mutation in exon 3, a cysteine residue is replaced with tyrosine in the cysteine-rich domain of the alpha subunit. The Y864X in exon 13 results in a truncated receptor, which is devoid of most of the beta subunit. This mutant receptor could not be expressed on a cell membrane since the transmembrane domain is missing. Other significant mutations were not found for the entire coding regions and splice/donor sites.


Subject(s)
Codon, Nonsense , Insulin Resistance/genetics , Mutation, Missense , Receptor, Insulin/genetics , Adolescent , Adult , Amino Acid Substitution , Codon/genetics , Female , Humans , Male , Sequence Analysis, DNA
3.
Acta Histochem ; 102(2): 151-7, 2000 May.
Article in English | MEDLINE | ID: mdl-10824608

ABSTRACT

Anti-rat CD45RA monoclonal antibody (MAb) has been used as a marker for rat B-lymphocytes (B-cells). When we applied the MAb to identify B-lymphocytes among immune cells infiltrating pancreatic islets of the BB rat, which is an animal model for human type 1 diabetes mellitus, a subpopulation of islet cells was immunostained as well. Our immunohistochemical investigations demonstrated that the stained islet cells are pancreatic alpha-cells and the MAb cross-reacts with glucagon.


Subject(s)
Antibodies, Monoclonal/immunology , Glucagon/immunology , Leukocyte Common Antigens/immunology , Animals , Antibody Specificity , B-Lymphocytes/immunology , Cross Reactions , Immunohistochemistry , Islets of Langerhans/pathology , Mice , Mice, Inbred NOD , Pancreas/pathology , Protein Tyrosine Phosphatase, Non-Receptor Type 1 , Rats , Rats, Inbred BB , Rats, Inbred Lew
4.
J Pediatr Endocrinol Metab ; 13(1): 91-8, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10689643

ABSTRACT

Nonobese diabetic mice develop type 1 diabetes in an age-related and gender-dependent manner. Th1 (IFN-gamma and TNF-beta) and Th2 (IL-4 and IL-10) cytokine mRNA expression was analyzed in pancreatic islets isolated from female NOD mice with a high incidence of diabetes and male NOD mice with a low incidence of diabetes. The levels were measured at 5 time points from the onset of insulitis until the development of overt diabetes, using a semiquantitative reverse transcriptase PCR (RT-PCR) assay. IFN-gamma mRNA levels were significantly higher in the islets obtained from females than those of males, from 10 weeks of age. TNF-beta mRNA was expressed in both females and males between 5 and 15 weeks of age. However, TNF-beta mRNA levels were decreased in males at 20 weeks of age. In contrast, IL-4 mRNA levels were lower in females than in males. These results suggest that islet beta-cell destruction and diabetes in female NOD mice correlates with IFN-gamma and TNF-beta production in the islets, and that male NOD mice may be protected from autoimmune beta-cell destruction by down-regulation of these cytokines. Furthermore, our findings also suggest that insulitis and beta-cell destruction are independently regulated: TNF-beta is more important in forming and maintaining the insulitis, while IFN-gamma has a more important role in beta-cell destruction.


Subject(s)
Cytokines/genetics , Diabetes Mellitus, Type 1/metabolism , Gene Expression , Islets of Langerhans/metabolism , RNA, Messenger/analysis , Animals , Female , Interferon-gamma/genetics , Interleukin-10/genetics , Interleukin-4/genetics , Lymphotoxin-alpha/genetics , Male , Mice , Mice, Inbred NOD , Reverse Transcriptase Polymerase Chain Reaction , Sex Characteristics
5.
J Pediatr ; 136(1): 111-3, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10636984

ABSTRACT

A very young male infant with Omenn's syndrome had acquired hypothyroidism that was most likely caused by autoimmune thyroiditis. The hypothyroidism appeared at 3 months of age. These 2 rare conditions have not previously been reported occurring together. This case suggests that autoimmune thyroiditis may be another abnormal finding in Omenn's syndrome.


Subject(s)
Histiocytic Sarcoma/complications , Hypothyroidism/etiology , Follow-Up Studies , Histiocytic Sarcoma/drug therapy , Humans , Hypothyroidism/drug therapy , Immunosuppressive Agents/therapeutic use , Infant , Male , Thyroiditis, Autoimmune/drug therapy , Thyroiditis, Autoimmune/etiology , Thyroxine/therapeutic use
7.
Transplantation ; 65(12): 1543-8, 1998 Jun 27.
Article in English | MEDLINE | ID: mdl-9665068

ABSTRACT

BACKGROUND: Previous reports on experimental islet transplantation in animal models of human insulin-dependent diabetes mellitus show that islet grafts are susceptible to autoimmune destruction similar to that seen in native pancreatic islets. In this study, we demonstrated a lack of disease recurrence in diabetic BioBreeding (BB) rats after syngeneic and allogeneic islet transplantation. METHODS: Four hundred to 1200 islets from BB (RT1u) and Lewis (RT1(1)) donors, isolated with stationary collagenase digestion and Ficoll density purification, were intraportally transplanted into spontaneously diabetic BB rats. The recipients received no immunologic manipulations before or after islet transplantation. RESULTS: When more than 900 syngeneic islets or when more than 600 allogeneic islets were transplanted, BB recipients remained normoglycemic for over 280 days, irrespective of age at onset, duration of exogenous insulin treatment, or age at transplantation. When at least 500 islets were transplanted, the recipients survived for a long period with normoglycemia or in a noninsulin-dependent diabetic state. Upon histological examination, mononuclear cell infiltration was observed in every islet graft examined, but the severity of infiltration in most of the grafts was mild to moderate. These results indicate that the islet grafts in the BB recipients were destroyed extremely slowly. CONCLUSIONS: It is conceivable that in our BB colony, a state of immunologically low responsiveness that allows diabetic animals to accept syngeneic or allogeneic islet grafts, occurs around the onset period and becomes more pronounced with aging. Our BB rat colony can be considered to be a novel substrain with unique immunological characteristics.


Subject(s)
Diabetes Mellitus, Type 1/prevention & control , Islets of Langerhans Transplantation , Animals , Male , Rats , Rats, Inbred Lew , Recurrence , Transplantation, Homologous , Transplantation, Isogeneic
8.
J Pediatr Endocrinol Metab ; 11(2): 267-72, 1998.
Article in English | MEDLINE | ID: mdl-9642642

ABSTRACT

This report describes the results of IGF-I treatment in a NOD mouse colony with a high incidence of overt diabetes. The animals were treated with IGF-I 17.9 nmol/day at 28-41 days of age and 35.9 nmol/day at 42-69 days of age and observed up to 280 days of age. Three of 12 (25%) IGF-I-treated animals developed diabetes compared with 8 of 11 (73%) controls (P < 0.05). The severity of insulitis at the conclusion of the follow-up was less pronounced in non-diabetic treated animals than in non-diabetic controls. These data support previous findings that IGF-I treatment protects the pancreatic beta-cells from destruction by diabetic autoimmunity in NOD mice.


Subject(s)
Diabetes Mellitus, Type 1/prevention & control , Insulin-Like Growth Factor I/therapeutic use , Animals , Female , Insulin/blood , Insulin-Like Growth Factor I/administration & dosage , Male , Mice , Mice, Inbred NOD
10.
Diabetes Res Clin Pract ; 34(1): 7-11, 1996 Sep.
Article in English | MEDLINE | ID: mdl-8968685

ABSTRACT

It has been shown that prophylactic exogenous insulin treatment prevents the development of insulin-dependent diabetes mellitus (IDDM) in animal models and humans. In this study, we examined whether the development of diabetes and insulitis in female non-obese diabetic (NOD) mice could be affected by prophylactic administration of insulin-like growth factor I (IGF-I), which shares structural homology with insulin and has insulin-like metabolic effects. Two experiments which differed in duration and dosage of IGF-I treatment were carried out. In the first experiment, animals were treated from 4 to 9 weeks of age with IGF-I (17.9 nmol/day at 4-5 weeks of age and 35.9 nmol/day at 6-9 weeks of age) and observed up to 34 weeks of age. In the second experiment, the animals were treated from 4 to 34 weeks of age with IGF-I (1.79 nmol/day at 4-5 weeks of age, 3.59 nmol/day at 6-9 weeks of age, and 5.38 nmol/day at 10-34 weeks of age). The former treatment could significantly delay the onset of diabetes (P < 0.05) and decrease the insulitis score at 10 weeks of age (P < 0.01). On the other hand, the latter treatment did not affect the incidence of diabetes, the age at onset or the insulitis score. Our results suggest that the IGF-I treatment at the early age may provide protection against autoimmune beta-cell destruction in NOD mice.


Subject(s)
Aging , Diabetes Mellitus, Type 1/prevention & control , Insulin-Like Growth Factor I/pharmacology , Islets of Langerhans/pathology , Analysis of Variance , Animals , Blood Glucose/drug effects , Blood Glucose/metabolism , Diabetes Mellitus, Type 1/genetics , Diabetes Mellitus, Type 1/pathology , Female , Incidence , Insulin/blood , Islets of Langerhans/drug effects , Mice , Mice, Inbred NOD
11.
J Pediatr Endocrinol Metab ; 9(3): 429-33, 1996.
Article in English | MEDLINE | ID: mdl-8887155

ABSTRACT

We report a child with a female phenotype possessing a karyotype of 46,XY,13p+. The child had female external genitalia, and manifested severe mental retardation, pulmonary atresia and multiple congenital abnormalities. Laparoscopy revealed the presence of streak gonads and Müllerian structures. Histological examination of the gonads showed ovarian-like stroma with immature seminiferous tubules. Chromosome and gene analyses demonstrated Xp11.23 (or 11.3)-pter duplication and an intact sex determinating factor of Y (SRY). The findings of this case suggest that duplication of Xp causes sex reversal in the presence of SRY.


Subject(s)
Disorders of Sex Development/genetics , Nuclear Proteins , Sex Chromosome Aberrations , Transcription Factors , X Chromosome , DNA-Binding Proteins/genetics , Disorders of Sex Development/pathology , Female , Genitalia/pathology , Humans , Infant, Newborn , Karyotyping , Male , Multigene Family , Ovary/pathology , Polymerase Chain Reaction , Polymorphism, Single-Stranded Conformational , Seminiferous Tubules/pathology , Sex-Determining Region Y Protein
13.
Biosci Biotechnol Biochem ; 60(2): 309-15, 1996 Feb.
Article in English | MEDLINE | ID: mdl-9063979

ABSTRACT

The ompC gene expression is induced by increasing temperature as well as osmotic pressure. In this study, a mutant (TD2) defective in this thermoresponse was isolated with transposon Tn10; the mutation was complemented by pMAN55 or pMAN56 containing micF and mapped at 48 min on Escherichia coli K-12. Furthermore, a new gene (hrsA) that suppressed the mutation was cloned. Its nucleotide sequence was analyzed and it was located close to the suc operon at 16.7 min corresponding to #18F11 (Kohara bank) on E. coli genome. In TD2 containing the hrsA on a multicopy plasmid, the ompC expression was induced and dependent on OmpR with increased temperature. The HrsA was found to have Enzyme IIA, IIB, and IIC domains that are homologous to Enzyme II, involved in the fructose-specific PTS (phosphotransferase system). The putative phosphorylation sites (His87 and Cys192) were also conserved in HrsA.


Subject(s)
Escherichia coli/genetics , Genes, Bacterial , Amino Acid Sequence , Bacterial Outer Membrane Proteins/biosynthesis , Bacterial Outer Membrane Proteins/genetics , Base Sequence , Cloning, Molecular , Gene Expression Regulation, Bacterial , Hot Temperature , Molecular Sequence Data , Mutation , Sequence Homology, Amino Acid
14.
Acta Paediatr Jpn ; 36(6): 637-41, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7871973

ABSTRACT

The inhibitory effects of diazoxide or polymyxin B on 3-O-methylglucose uptake were studied in isolated rat erythrocytes or adipocytes to elucidate the mechanisms of the actions of these agents. One to three mmol/L diazoxide significantly inhibited 3-O-methylglucose uptake into erythrocytes by 11-33% without altering the equilibrium space, while 0.3 mmol/L diazoxide did not. The inhibitory effect was exerted in a dose-dependent manner in this concentration range. To test whether polymyxin B affects the process of insulin action or the glucose transport activity recruited by insulin, adipocytes prestimulated with insulin and exposed to 2 mmol/L potassium cyanide (KCN) were employed since the cells, on which glucose transporters recruited by insulin were located quiescently, were useful to estimate the effect of an agent on glucose transport activity per se. Polymyxin B (100 micrograms/mL) inhibited the insulin-stimulated uptake activity in this transport system by 22.5% while it inhibited the insulin-stimulated uptake activity in intact adipocytes which were not exposed to KCN by 32.2%. These results suggest that diazoxide inhibits the function of the erythrocyte glucose transporter, GLUT1 (classified by Bell et al.), and indicate that the inhibition of the glucose transport activity recruited by insulin is the major effect of polymyxin B (100 micrograms/mL) and the inhibition of the process of insulin action is rather small.


Subject(s)
Adipocytes/metabolism , Diazoxide/pharmacology , Erythrocytes/metabolism , Methylglucosides/antagonists & inhibitors , Methylglucosides/pharmacokinetics , Polymyxin B/pharmacology , Rats, Wistar , 3-O-Methylglucose , Adipose Tissue/drug effects , Animals , Culture Techniques , Dose-Response Relationship, Drug , Insulin/pharmacology , Male , Potassium Cyanide/pharmacology , Rats
15.
Jpn J Antibiot ; 47(11): 1565-75, 1994 Nov.
Article in Japanese | MEDLINE | ID: mdl-7853687

ABSTRACT

Blood and urine levels of cefozopran (CZOP) were determined, and its efficacy and safety profile was evaluated in the field of pediatrics. The results of this study are summarized as follows. 1. Blood levels of CZOP peaked in 30 minutes to 1 hour (initial blood collection) after intravenous administration at a dose of 20 or 40 mg/kg. Its blood levels at 6 hours after intravenous administration were 1.6 micrograms/ml (HPLC) or 1.9 micrograms/ml (bioassay) at a dose of 20 mg/kg and 2.9 to 9.1 micrograms/ml (HPLC) or 2.9 to 8.4 micrograms/ml (bioassay) at a dose of 40 mg/kg. The half-lives were 1.58 to 2.27 hours (HPLC) and 1.53 to 1.85 hours (bioassay), respectively. The rate of recovery of CZOP in the urine in the first 8 hours after intravenous administration at a dose of 20 mg/kg was 61.5% (HPLC) or 54.6% (bioassay), and urine levels of CZOP at 6 to 8 hours after administration were 157.3 micrograms/ml (HPLC) and 129.7 micrograms/ml (bioassay). 2. When CZOP was administered to 16 patients with respiratory tract infections, 2 patients with urinary tract infections, 2 patients with acute enteritis, 1 patient with skin soft tissue infection, and 1 patient with purulent lymphadenitis, the responses were excellent in 68% of patients and good in 32% with an overall efficacy rate of 100%. 3. Bacteriological effect of CZOP was excellent and the rate of bacterial eradication was 100% (9/9). 4. MICs of CZOP against clinical isolates (Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Streptococcus pneumoniae, Escherichia coli, Moraxella (Branhamella) catarrhalis) were compared to those of other injectable cephems ceftazidime (CAZ), cefuzonam (CZON), flomoxef (FMOX), cefmetazole (CMZ). The MICs of cefozopran (CZOP) against Gram-positive organisms, S. aureus, MRSA, and S. pneumoniae, were nearly as low as those of CZON and were clearly lower than those of CAZ. MICs of CZOP against Gram-negative organisms were examined and the MIC against E. coli was as low as those of other antibiotics but the MIC of CZOP against M. (B.) catarrhalis was higher, at 1.56 micrograms/ml, than those of CAZ, FMOX, and CMZ. 5. Diarrhea was experienced by 1 of 22 patients as a side effect from CZOP, and abnormal laboratory tests including increases of eosinophil counts in 2 patients (9.1%), a decrease of neutrophil counts in 1 patient (4.5%), thrombocytosis in 1 patient (4.5%), and an elevation of GPT in 3 patients (13.6%).(ABSTRACT TRUNCATED AT 400 WORDS)


Subject(s)
Bacterial Infections/drug therapy , Cephalosporins/therapeutic use , Bacteria/drug effects , Bacteria/isolation & purification , Bacterial Infections/metabolism , Bacterial Infections/microbiology , Cephalosporins/pharmacokinetics , Cephalosporins/pharmacology , Child , Child, Preschool , Drug Resistance, Microbial , Female , Humans , Infant , Injections, Intravenous , Male , Cefozopran
16.
Acta Paediatr Jpn ; 36(4): 412-5, 1994 Aug.
Article in English | MEDLINE | ID: mdl-7942006

ABSTRACT

A case of a 6 year old boy with Kabuki make-up syndrome with central diabetes insipidus and growth hormone neurosecretory dysfunction is reported. Magnetic resonance imaging revealed abnormal findings of the pituitary gland and stalk. Good catch-up growth was obtained by treatment with growth hormone. These findings suggest that hypothalamic-pituitary dysfunction might be involved in Kabuki make-up syndrome.


Subject(s)
Abnormalities, Multiple , Diabetes Insipidus/complications , Facial Expression , Growth Hormone/metabolism , Child , Humans , Hypothalamo-Hypophyseal System/physiopathology , Male , Pituitary Gland/abnormalities , Syndrome
17.
Acta Paediatr Jpn ; 36(2): 128-32, 1994 Apr.
Article in English | MEDLINE | ID: mdl-8203255

ABSTRACT

The effect of diazoxide on 3-O-methylglucose (3-O-MG) transport was studied in isolated rat adipocytes to elucidate its extrapancreatic action. Diazoxide (0.3-3 mmol/L) significantly inhibited 3-O-MG uptake into adipocytes in a basal state or an insulin-stimulated state. The inhibitory effect was mainly due to the inhibition of insulin responsiveness for 3-O-MG uptake. The insulin responsiveness is determined by the capacity in the process of insulin action and in the final glucose transport activity, and diazoxide mainly inhibited the 3-O-MG transport activity itself. Based on these findings, this extrapancreatic action of diazoxide is considered to contribute partially to raising the blood glucose level in children receiving the drug. Diazoxide, as a glucose transport inhibitor, may be a useful tool for studying the issues related to glucose transport or insulin action.


Subject(s)
Adipocytes/metabolism , Diazoxide/pharmacology , Methylglucosides/pharmacokinetics , 3-O-Methylglucose , Adipocytes/drug effects , Animals , Biological Transport/drug effects , Cells, Cultured , Rats , Rats, Wistar
18.
Acta Paediatr Jpn ; 36(1): 20-4, 1994 Feb.
Article in English | MEDLINE | ID: mdl-8165903

ABSTRACT

The effects of peroxovanadate or tungstate on 3-O-methylglucose uptake were characterized using isolated rat adipocytes to elucidate the mechanism(s) of their actions. The stimulatory effect of peroxovanadate was observed from 1 mumol/L and reached the maximum at about 100 mumol/L. The concentration showing the half-maximal effect was approximately 16 mumol/L. The maximal response of peroxovanadate was 1.19 times higher than that of insulin significantly (P < 0.01). On the other hand, the stimulatory effect of tungstate was seen only at the higher concentrations of 10-30 mmol/L. Judging from the experiments using different tungsten compounds, tungstic acid (WO4(2-)) appeared responsible for the effect. The effects of 20 mmol/L tungstate and 20 nmol/L insulin were not additive. The stimulatory effects of 1 mmol/L peroxovanadate, 20 mmol/L tungstate or 20 nmol/L insulin were not seen in the adipocytes deprived of ATP by exposure to 2 mmol/L KCN. The adipocytes which had been stimulated with insulin and further exposed to 2 mmol/L KCN were used to test whether or not peroxovanadate works directly on the function of glucose transporters. In such cells on which GLUT4-rich transporters were rendered immobile, the effect of peroxovanadate was not observed. These results indicate that the effects of peroxovanadate or tungstate are ATP or energy dependent and may be exerted through the mechanism analogous to that of insulin action, and suggest that peroxovanadate does not directly activate the function of GLUT4.


Subject(s)
Adipocytes/metabolism , Glucose/metabolism , Tungsten Compounds/pharmacology , Vanadates/pharmacology , Animals , Biological Transport/drug effects , Cell Separation , Male , Rats , Rats, Wistar
19.
Diabetes Res Clin Pract ; 22(2-3): 147-54, 1994 Jan.
Article in English | MEDLINE | ID: mdl-8200296

ABSTRACT

Autoimmunity in Type 1 (insulin-dependent) diabetes mellitus was assessed by measuring thyroglobulin antibodies (TGA) using a highly sensitive enzyme immunoassay in 65 young patients with Type 1 diabetes mellitus, 83 healthy first-degree relatives of the patients, 37 healthy control subjects and 67 healthy parents of the control subjects. TGA were found in 78.5% (51/65) of patients and were significantly more frequent in patients than in control subjects (40.5%, 15/37; P < 0.01). The prevalence of TGA in patients showed no correlation with age at onset, duration of diabetes or sex. Among the first-degree relatives the prevalence of TGA was significantly increased in mothers of patients than in mothers of the control subjects (80.0% vs. 54.3%, P < 0.05), while not significantly between fathers of patients and fathers of control subjects or between siblings of patients and control subjects. Comparing the TGA levels of TGA-positive subjects, the TGA levels in patients, their parents and their siblings were significantly higher than those in the corresponding control subjects (P < 0.05, P < 0.05 and P < 0.01, respectively). In the present study we thus more clearly demonstrated autoimmune diathesis in patients with Type 1 diabetes and in their first-degree relatives.


Subject(s)
Autoantibodies/blood , Diabetes Mellitus, Type 1/genetics , Diabetes Mellitus, Type 1/immunology , Thyroglobulin/immunology , Adolescent , Adult , Age of Onset , Child , Child, Preschool , Diabetes Mellitus, Type 1/blood , Female , Humans , Immunoenzyme Techniques , Male , Nuclear Family , Reference Values , Sensitivity and Specificity , Sex Factors
20.
Diabetes Res Clin Pract ; 20(1): 1-5, 1993 Apr.
Article in English | MEDLINE | ID: mdl-8344124

ABSTRACT

The effect of amiloride on 3-O-methylglucose (3-O-MG) uptake was studied in isolated rat adipocytes to define to what extent amiloride inhibited the process of insulin action or glucose transport. Amiloride (1 mM), which did not change the intracellular water space of adipocytes, inhibited by 43.3% the insulin-stimulated uptake of 3-O-MG, while it did not appear to inhibit the basal uptake. To distinguish the inhibitory effect on glucose transport activity from that on the process of insulin action, the effect of amiloride was evaluated in the transport system using adipocytes deprived of ATP, in which glucose transporters were considered immobile. Amiloride (1 mM) inhibited this transport by 32.8% in an insulin-stimulated state, which was obtained using adipocytes that had been treated with 20 nM insulin and exposed to 2 mM KCN, whereas it did not inhibit the transport system at the basal state. In the inhibitory effect, 76% was thus attributable to the inhibition of glucose transport activity recruited by insulin and 24% to the inhibition of the action of 20 nM insulin itself. These results indicate that amiloride can not be used as a specific inhibitor of the insulin action itself.


Subject(s)
Adipose Tissue/metabolism , Amiloride/pharmacology , Insulin/pharmacology , Methylglucosides/metabolism , 3-O-Methylglucose , Adipose Tissue/drug effects , Animals , Cells, Cultured , Dose-Response Relationship, Drug , Intracellular Fluid/drug effects , Intracellular Fluid/metabolism , Kinetics , Male , Potassium Cyanide/pharmacology , Rats , Rats, Wistar
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