bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vivo pH of Induced Soft-Tissue Abscesses in Diabetic and Nondiabetic Mice
Authors: Bessman Alice N , Page Jettie , Thomas Lyell J
Published: September 2013

Infections in the diabetic host have been shown to persist longer than those in the nondiabetic host. To investigate whether intra-abscess milieu might be a contributing factor to this persistence, the in vivo intra-abscess pH was measured in induced soft-tissue abscesses in diabetic and nondiabetic mice. Two models (female genetically obese insulin-resistant and male streptozocin-induced diabetic mice) were used with appropriate controls. The bacteria injected to produce the soft-tissue abscesses were Bacteroides fragilis and Enterococcus (B + E), Staphylococcus epidermidis and Enterococcus (S + E), and S. aureus (SA). Intra-abscess pH measured on day 3 was consistently and significantly lower in all diabetic mice compared with their controls. In the diabetic mice, the pH of an abscess induced with B + E, S + E, and SA was 6.28 (n = 17), 6.79 (n = 10), and 6.52 (n = 10), respectively; the pH in the controls was 7.21 (n = 20), 7.30 (n = 10), and 7.17 (n = 10), respectively. Differences in all groups between diabetic and nondiabetic mice were significant. The blood glucose values of the diabetic mice averaged 722 mg/dl, and in the nondiabetic mice were 210 mg/dl. No animals were ketotic. There were no significant differences in total colony counts between any groups. In conclusion, there is a significantly lower pH in the abscess of the diabetic host compared with the nondiabetic host that is not related to the numbers or types of causative bacteria.
Characterization of Insulinlike Growth Factor I Produced by Fetal Rat Pancreatic Islets
Authors: Scharfmann Raphaël , Corvol Maité , Czernichow Paul
Published: September 2013

Pancreatic islets were prepared from 22-day-old rat fetuses. After 5 days of culture in dishes allowing cell attachment, neoformed islets were kept free floating in RPMI-1640 medium (16.5 mM glucose, 1% fetal calf serum). The islets were then pulsed with [3H]leucine and [35S]methionine for 24 h. The conditioned medium was acidified with acetic acid (final pH 2.7), desalted, concentrated, and gel filtered on Bio-Gel P100 in acid conditions. The radioactive material that comigrated with immunoreactive insulinlike growth factor I (IGF-I) produced by the islets was pooled, concentrated, and further characterized by reverse-phase high-performance liquid chromatography on a C18Bondapak column with a linear gradient of acetonitrile (20–80%). The radioactive material that eluted as pure IGF-I (40% acetonitrile) was further studied by chromatofocusing on a Pharmacia PBE 94 column. A sharp radioactive peak containing [3H]leucine and [35S]methionine was eluted at pH 8.55. This material was immunoprecipitated with an antiserum to IGF-I. This study demonstrated that fetal islet cells synthesize molecules that are, by several criteria, equivalent to native IGF-I.
Metabolic Effects of Long-Acting Somatostatin Analogue (Sandostatin) in Type I Diabetic Patients on Conventional Therapy
Authors: Osei Kwame , O'Dorisio Thomas M , Malarkey William B , Craig Elson L , Cataland Samuel
Published: September 2013

We evaluated the effectiveness of a more potent and longer-acting somatostatin analogue (SMS 201–995) as an adjunct to insulin therapy, in a double-blind placebo-controlled randomized study of 26 C-peptide-negative type I (insulin-dependent) diabetic patients (20 women, 6 men, aged 22–40 yr) on their conventional drug regimens for 12 wk. Eight patients received a low dose (10 μg) of the analogue, 9 received a high dose (50 μg) of the analogue, and 9 received placebo subcutaneously before breakfast and dinner. Twenty-four-hour serum glucose, free insulin, plasma growth hormone (GH), and glucagon profiles were obtained before and during treatment at 4-wk intervals. The mean age, duration of diabetes, daily insulin dose, and body weight were not significantly different among the groups. The mean weekly capillary blood glucose values and exogenous insulin requirements were not changed by the SMS 201–995 therapy. Mean glycosylated hemoglobin A1 levels were unchanged in both the analogue- and placebo-treated groups at wk 12. Basal and postprandial glucose, free insulin, GH, and glucagon profiles were not influenced by the SMS 201–995 therapy throughout the study. Nocturnal glucose turnover rates (D-[3-3H]glucose technique) remained unaltered by the analogue therapy. Dose-dependent gastrointestinal (GI) adverse effects (e.g., diarrhea) were documented in the analogue-treated patients. Visual acuity and fundic photomicrographs of our patients were not changed by the analogue therapy. In conclusion, the prominent adverse GI effects our patients experienced preclude the use of larger doses of the analogue that may be necessary to suppress GH and glucagon and improve glucose control in type I diabetic patients.
Plasma 1,5-Anhydro-D-Glucitol as New Clinical Marker of Glycemic Control in NIDDM Patients
Authors: Yamanouchi Toshikazu , Minoda Susumu , Yabuuchi Masahiko , Akanuma Yasuo , Akanuma Hiroshi , Miyashita Hideo , Akaoka Ieo
Published: September 2013

To elucidate the value of using plasma 1,5-anhydro-D-glucitol (AG) as a marker of glycemic control in diabetic patients, the relationship between the plasma concentration of AG and glucosuria was examined in 152 patients with non-insulin-dependent diabetes mellitus (NIDDM). After recovery from the deterioration of glycemic control in NIDDM patients had started, AG began to increase day by day. The recovery of plasma AG showed a constant linear increase curve when excellent glycemic control was attained. The ordinary daily recovery rate of plasma AG was estimated to be 0.3 μg/ml, which was independent of body weight, sex, age, the difference in treatment, the duration of diabetes, or the level of plasma AG among NIDDM patients. This rate decreased according to the increase in urinary glucose. When we calculated the decrease rate of plasma AG (ΔAG), assuming 0.3 μ/day to be the maximum increase rate in a day, we found a high correlation between βAG and urinary glucose at almost all AG levels except the normal range and observed that plasma AG ((A)) times urinary glucose (G) was relatively constant. The formula A × G = 16 is a simple equation for rough estimation of urinary glucose from the plasma AG concentration in a stable glycemic-controlled NIDDM patient, and we call it the A ⋅ G index. The plasma AG also correlated significantly with fasting plasma glucose (r = −.810) and glycosylated hemoglobin (r = −.856) in the same stable glycemic-controlled NIDDM patients. Based on these observations, we propose that plasma AG can serve as a new marker that may provide sensitive and analytical information about glycemic control.
Effects of Interrupted Insulin Treatment on Fetal Outcome of Pregnant Diabetic Rats
Authors: Eriksson Roger S M , Thunberg Lennart , Eriksson Ulf J
Published: September 2013

Streptozocin-induced diabetic female rats became normoglycemic after subcutaneous insertion of insulin-releasing osmotic minipumps. These female rats were mated with normal males from the same Sprague-Dawley substrain. In this substrain, the offspring of diabetic rats show a markedly increased congenital malformation rate compared with fetuses of nondiabetic rats. The pregnant diabetic rats were subjected to removal and insertion of pumps at defined gestational days that marked the beginning or end of a 2- or 4-day period of insulin withdrawal. Evaluation of the offspring on day 20 of pregnancy included fetal/placental weights, estimated number of implants, resorptions, and morphological assessment of congenital malformations. Resorptions occurred in all interruption groups, but malformations were found only in animals with insulin withdrawal on gestational days 4–8, 6–8, 6–10, 8–10, and 8–12. The highest resorption (42%) and malformation (17%) rates were found in the rats subjected to insulin withdrawal during gestational days 6–10. Because manifestly diabetic rats with no insulin treatment showed similar resorption (39%) and malformation (17%) rates, this study suggests that a teratogenic period in diabetic rat pregnancy occurs during gestational days 6–10, a period corresponding to postconceptional wk 2–4 in human pregnancy. Interruption of insulin treatment induced similar maternal weight loss and similar maternal serum concentrations of D-glucose, cholesterol, urea, and creatinine in rats with and without malformed offspring. Although the teratogenic agents of diabetic pregnancy in this animal model remain to be identified, the simultaneously high levels of serum β-hydroxybutyrate and triglycerides in the rats with the highest malformation rate suggest that the teratogenic environment may include a severe disturbance in maternal lipid metabolism in addition to glucose dysregulation.
Control of Glycogen Synthase and Phosphorylase in Hepatocytes From Diabetic Rats: Effects of Glucagon, Vasopressin, and Vanadate
Authors: Rodríguez-Gil Joan E , Gómez-Foix Anna M , Ariño Joaquín , Guinovart Joa J , Bosch Fátima
Published: September 2013

Although glycogen synthase is present in a highly inactivated state in hepatocytes from streptozocin-induced diabetic rats, glucagon, vasopressin, and vanadate are still able to further decrease the basal activity of the enzyme. This inactivation was observed with the low-to-high glucose 6-phosphate activity ratio assay. The inactivation of glycogen synthase occurred concomitantly with the activation of glycogen phosphorylase. When hepatocytes from diabetic rats were incubated with [32P]phosphate and then with the agents and when the 32P-labeled glycogen synthase was immunoprecipitated, we observed that the 32P bound to the 88,000-M subunit increased in all cases. All the [32P]phosphate was located in two cyanogen bromide fragments of the enzyme, indicating that the enzyme was phosphorylated at multiple sites. The fragments were precisely those phosphorylated by glycogenolytic hormones in hepatocytes from normal rats. These results demonstrated that hepatic glycogen synthase, although highly inactive, is under potential hormonal control in diabetes and that the enzyme has not reached its maximal level of phosphorylation. Furthermore, they indicated that vanadate behaves as a glycogenolytic agent regarding its effects on glycogen-metabolizing enzymes in hepatocytes from diabetic rats.
Insulin and Glucagon Secretion After Pancreatectomies Correlation of Secretion and Hormonal Contents of Remaining Pancreas
Authors: Gotoh Mitsukazu , Monden Morito , Okamura Jun , Mori Takesada , Shima Kenji
Published: September 2013

We studied whether insulin and glucagon secretory capacities change in relation to the corresponding hormonal contents in the pancreas remnant after pancreas resection. The following groups of dogs were used: sham operated (S-O), left pancreatectomized (L-Px), right pancreatectomized (R-Px), subtotal pancreatectomized (St-Px), and total pancreatectomized (T-Px). Endocrine functions were assessed by intravenous glucose tolerance test (IVGTT) and insulin tolerance test (ITT) in each dog under anesthesia before surgery and 1 wk after. In these five groups, the insulin secretory capacities, assessed as the integrated incremental secretion of immunoreactive insulin (ΣΔIRI) from the IVGTT, decreased to 95 ± 11, 78 ± 9, 48 ± 8, 12 ± 8, and −4 ± 4% of the respective preoperative values, and these values were proportional to the percentage residual weight (100, 64 ± 2, 35 ± 2, 13 ± 2, 0%) and IRI content (100, 59 ± 4, 45 ± 3, 10± 2, 0%) of the pancreas remnant. After surgery, glucagon secretory capacity, the integrated incremental secretion of immunoreactive glucagon (ΣΔIRG) during the ITT, decreased significantly in the L-Px, St-Px, and T-Px groups but not in the R-Px group. The ΣΔIRG values as percentages of the preoperative values were 109 ± 25, 46 ± 11, 89 ± 13, 19 ± 11, and 3 ± 3%, respectively, for the five groups. These values were proportional to the percentage residual IRG contents of the pancreas remnants (100, 48 ± 6, 65 ± 8, 12 ± 2, 0%) rather than to the percentage residual pancreatic weights. Significant correlations were found between the percentage ΣΔIRI and IRI contents (r = .876, P <.001) and the percentage ΣΔIRG and IRG contents (r = .775, P <.001) after surgery in individual dogs. The results indicate that the hormonal secretory capacity of these dogs was influenced by the hormone-containing functional mass rather than the weight of the pancreas itself after surgery and that the uneven distribution of glucagon in the pancreas (predominantly concentrated in the tail of the pancreas) should be taken into consideration when discussing hormonal deficiency after pancreatectomy.
Erythrocyte O2 Transport and Metabolism and Effects of Vitamin B6 Therapy in Type II Diabetes Mellitus
Authors: Solomon Lawrence R , Cohen Kenneth
Published: September 2013

The effects of vitamin B6 on erythrocyte metabolism, erythrocyte hemoglobin O2 affinity (P50), and nonenzymatic glycosylation were studied in 15 Caucasian men with type II (non-insulin-dependent) diabetes mellitus. A control group of 13 healthy Caucasian men was also evaluated. Before treatment, diabetic subjects had low mean cell hemoglobin concentration values and increases in both erythrocyte 2,3-diphosphoglycerate (2,3-DPG) levels and erythrocyte hexokinase activities. Although all three of these changes are associated with a decrease in hemoglobin O2 (Hb-O2) affinity, P50 values were normal in diabetic subjects. Moreover, P50 values normalized to pH 7.4 (P507.4) were inversely related to the level of glycosylated hemoglobin (HbA1c). Both erythrocyte 2,3-DPG and erythrocyte ATP were also inversely related to HbA1c. Vitamin B6 nutriture, as determined by erythrocyte aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities, was normal in all diabetic subjects before vitamin B6 therapy. Nonetheless, HbA1c levels decreased after 6 wk of treatment with 150 mg/day pyridoxine and increased again during placebo administration. These changes were not explained by changes in fasting blood glucose. Pyridoxine therapy also decreased P507.4values and increased erythrocyte AST and ALT activities but had no effect on 2,3-DPG, ATP, or the activities of hexokinase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase. These observations suggest that 1) nonenzymatic glycosylation may play a role in regulating both erythrocyte metabolism and Hb-O2affinity in diabetic subjects, and 2) vitamin B6 therapy may modify nonenzymatic glycosylation of hemoglobin in this population.
Genetic Studies in Inbred BB/Wor Rats: Analysis of Progeny Produced by Crossing Lymphopenic Diabetes-Prone Rats With Nonlymphopenic Diabetic Rats
Authors: Guberski Dennis L , Butler Leonard , Kastern William , Like Arthur A
Published: September 2013

BB/Wor diabetes-prone (DP) rats are lymphopenic and frequently develop insulin-dependent diabetes. Diabetes-resistant (DR) BB/Wor rats are not lymphopenic and become diabetic rarely and at a significantly younger age. To examine the genetic basis for diabetes, lymphopenia, and age at onset of diabetes among inbred BB/Wor rats, we crossed nonlymphopenic diabetic rats with lymphopenic DP animals and studied F1, F2, and backcross progeny. F, rats were neither diabetic nor lymphopenic. Diabetes (both types) and lymphopenia reappeared among F2 rats, confirming the permissive association of diabetes and lymphopenia and the recessive nature of both. The absence of diabetes in F1 rats also suggested that the combination of genes responsible for diabetes among lymphopenic and nonlymphopenic rats may be distinct. Nonlymphopenic parental, F1, and F2 rats revealed normal lymphocyte subsets, including CD8+and RT6+ T-lymphocytes. Lymphopenic parental and F2 rats revealed the absence of CD8+ and RT6+ cells, indicating that these T-lymphocyte abnormalities of lymphopenic DP rats segregate with the lymphopenia gene. The distribution of the ages at onset of diabetes among F2 lymphopenic and F2 intercross rats was significantly earlier than among lymphopenic parental and backcross animals, suggesting that the age of diabetes onset is a heritable trait and that the gene(s) or genetic modifier(s) responsible for the earlier onset of F2 diabetes was acquired from the nonlymphopenic parents. Our genetic studies also confirmed the observations that the 2-and 7-kilobase Bam HI fragments of the MHC class I region do not correlate with diabetes or lymphopenia.
Reciprocal Allogeneic Bone Marrow Transplantation Between NOD Mice and Diabetes-Nonsusceptible Mice Associated With Transfer and Prevention of Autoimmune Diabetes
Authors: LaFace Drake M , Peck Ammon B
Published: September 2013

Reciprocal allogeneic bone marrow transplantations were carried out between diabetes-susceptible nonobese diabetic (NOD) and diabetes-nonsusceptible C57BL/6 or B10.BR/cd mice to examine the role of the immune system and host environment in the development of autoimmune diabetes. Serotyping of lethally irradiated hosts reconstituted with allogeneic bone marrow showed the hematopoietically derived cells to be of donor origin. Our results showed that lethally irradiated NOD mice reconstituted with a B10.BR/cd hematopoietic cell system remained totally free of insulitis, failed to develop diabetes, and thrived to old age. In contrast, lethally irradiated C57BL/6 or B10.BR/cd mice reconstituted with an NOD hematopoietic cell system all developed insulitis, but only ∼10% progressed to overt diabetes. Direct adoptive transfer of insulitis and diabetes by mature T-lymphocytes apparently was not required; analogous results were obtained when diabetes-nonsusceptible hosts were reconstituted with NOD hematopoietic cells containing T-lymphocytes or devoid of Thy-1+ cells. The difference in frequency for the development of insulitis versus insulitis plus overt diabetes in C57BL/6 and B10.BR/cd mice suggests that the hematopoietically derived immune cells from NOD mice were sufficient to induce anti-islet reactivity but may require the diabetogenic host environment to develop the frequency and severity of diabetes observed in NOD mice.
Zinc-Dependent Low Thymic Hormone Level in Type I Diabetes
Authors: Mocchegiani Eugenio , Boemi Massimo , Fumelli Paolo , Fabris Nicola
Published: September 2013

Zinc is required for optimal functioning of the immune system. It was recently reported that one of the best-known thymic hormones responsible for the maturation and differentiation of the thymus-derived T-lymphocyte line, i.e., serum thymic factor (STF), is biologically active only when bound to zinc ions; in this form it has been called thymulin (Zn-STF). Because low serum and tissue zinc values have been reported to occur in diabetic conditions, and because defects of T-lymphocyte–dependent functions are also present in diabetic patients, even metabolically well-controlled diabetic patients, we investigated the serum level of zinc and the plasma level of both active Zn-STF and inactive STF thymic hormones in 15 young patients suffering from type I (insulin-dependent) diabetes. Serum zinc levels were significantly reduced in diabetic conditions and did not correlate with the degree of metabolic compensation measured by glycosylated hemoglobin. In diabetes, the active form of thymulin is strongly reduced, whereas the inactive form is abnormally elevated. In vitro zinc addition to diabetic plasma samples also induces zinc saturation of inactive thymic hormone molecules: the total thymic hormone measured in these experimental conditions shows values in diabetic patients comparable with those observed in healthy age-matched individuals, suggesting that low thymulin levels recorded in diabetic conditions are due not to a thymic failure in synthesizing and secreting thymic hormone but to a peripheral defect in zinc saturation of the hormone molecules. The zinc-dependent failure of thymic hormone, present even in fairly compensated diabetic conditions, might account for the apparent insulin-independent immunological abnormalities associated with type I diabetes.
Anti-Sympathetic Nervous System Autoantibodies: Diminished Catecholamines With Orthostasis
Authors: Brown Florence M , Brink Stuart J , Freeman Roy , Rabinowe Steven L
Published: September 2013

The etiology of autonomic neuropathy in insulin-dependent diabetes mellitus (IDDM) is unknown. Previous studies have noted the presence of anti-adrenal medullary antibodies in IDDM. Recently, we have also demonstrated the presence of anti-sympathetic ganglia antibodies in IDDM. We initiated a study to evaluate whether subjects with complement-fixing anti-adrenal medullary (CF-ADM) and anti-sympathetic ganglia (CF-SG) antibodies have a decreased catecholamine response to change in posture. Seven IDDM subjects aged 19–41 yr with duration of disease 5–21 yr at the time of the posture study were evaluated. Serums collected longitudinally were evaluated for the presence of CF-ADM and CF-SG antibodies. Three IDDM subjects were CF-ADM− and CF-SG− at all testing intervals (Ab− group). Four IDDM subjects were CF-ADM+ and/or CF-SG+ on at least one testing date (Ab+ group). Baseline mean norepinephrine and epinephrine levels were not significantly different in Ab+ and Ab− subjects. Norepinephrine levels 5 min after standing were mean ± SD 227 ±16 and 419 ± 48 pg/ml for Ab+ and Ab− subjects, respectively (P < .03). The means of the 5-min minus basal norepinephrine levels were 88 ± 42 (Ab+) and 207 ± 26 (Ab−) pg/ml (P < .03). Mean epinephrine levels after 5 min of standing were 35 ±16 (Ab+) and 101 ± 44 (Ab−) pg/ml (P < .03). The means of the 5-min minus basal epinephrine levels were 1 ± 5 (Ab+) and 43 ± 38 (Ab) pg/ml (P < .03). Mean change in systolic blood pressure on standing was not different in the two groups. This suggests that CF-ADM and CF-SG are associated with a decreased catecholamine response to change in posture.
Inhibition of Polymorphonuclear Leukocyte Respiratory Burst by Elevated Glucose Concentrations in Vitro
Authors: Nelson Christopher P , Hindson David A
Published: September 2013

Although impaired polymorphonuclear leukocyte (PMN) function may be a cause of infectious complications in diabetic patients, the mechanisms of altered cell function are not understood. Our studies of PMN function in healthy subjects demonstrated significant reduction in the respiratory burst after 30 min of in vitro cell exposure to glucose concentrations >11 mM (200 mg/dl). The respiratory burst was reduced 28 ± 5 and 74 ± 7% in PMNs incubated with 11 and 56 mM glucose, respectively. The impairment was independent of the cell stimulus (chemotactic peptide, calcium ionophore, or phorbol ester) and was not affected by sorbinil or myo-inositol. Because both D- and L-glucose had similar inhibitory effects, a nonenzymatic mechanism appeared to be the cause of impaired PMN function. Although mannitol and sorbitol did not affect cell function, monosaccharides (glucose, mannose, fructose) that form Schiff-base adducts with protein inhibited PMN function. These findings suggest a potential role for protein glycosylation in glucose-induced impairment of PMN function.
Lack of Teratogenic Effect of Brief Maternal Insulin-Induced Hypoglycemia in Rats During Late Neurulation
Authors: Buchanan Thomas A , Sipos George F
Published: September 2013

We have previously shown that 1 h of maternal insulin-induced hypoglycemia is teratogenic to rat embryos during the initial stages of neurulation, when they are dependent on uninterrupted glycolysis (day 9.5–9.7 of development). To determine whether this vulnerability persists in later stages of neural tube and cardiac development, we infused insulin into 16 conscious pregnant rats for 1 h beginning after embryos had developed the capacity for aerobic glucose metabolism (day 10.6 of development). Half of the pregnant animals were allowed to become hypoglycemic (44 ± 2 mg/dl) during the insulin infusions. The other half received glucose infusions to maintain normoglycemia (130 ± 3 mg/dl). Normal plasma glucose levels were maintained in all animals after the insulin infusions. Embryos were examined on day 11.5 of development. At that time, 1 of 111 embryos from the normoglycemic group and 1 of 109 embryos from the hypoglycemic group were grossly malformed (P > .5). Means of embryo crown-rump length (4.15 ± 0.03 vs. 4.14 ± 0.03 mm), somite number (29.7 ± 0.1 vs. 29.8 ± 0.2), and total protein content (320 ± 5 vs. 326 ± 6 μg) were also similar in the two groups (P > .5). Thus, we could not detect an embryotoxic effect of 1 h of maternal insulin-induced hypoglycemia beginning at day 10.6 of development. This finding is in contrast to our prior demonstration that a similar period of hypoglycemia occurring earlier in neurulation (day 9.7) caused growth retardation and developmental anomalies in embryos. Our results indicate that the teratogenic effects of brief maternal insulin-induced hypoglycemia in vivo do not extend past early organogenesis in rats. Based on these findings and on clinical data indicating that maternal hypoglycemia is not teratogenic during later portions of the first trimester, we suggest that efforts to determine whether maternal insulin-induced hypoglycemia is teratogenic in humans should focus on the first 3 wk of intrauterine development.
Polymorphic Human Insulin-Responsive Glucose-Transporter Gene on Chromosome 17p13
Authors: Bell Graeme I , Murray Jeffrey C , Nakamura Yusuke , Kayano Toshiaki , Eddy Roger L , Fan Yao-Shan , Byers Mary G , Shows Thomas B
Published: September 2013

Glucose uptake by heart, skeletal muscle, and adipose tissue is acutely regulated by insulin, which stimulates facilitative glucose transport, at least in part, by promoting the translocation of transporters from an intracellular pool to the plasma membrane. cDNAs encoding the major human insulin-responsive glucose transporter have been isolated and indicate that the insulin-responsive glucose transporter expressed by heart, skeletal muscle, and adipose tissue is a 509–amino acid protein having 65.3, 54.3, and 57.5% identity with the erythrocyte/HepG2, liver, and fetal muscle glucose transporters, respectively. The gene encoding the insulin-responsive glucose transporter (designated GLUT4) was mapped to the p11 → p13 region of the short arm of human chromosome 17 by analyzing its segregation in a panel of reduced human-mouse somatic cell hybrids. In situ hybridization to prometaphase chromosomes indicated that GLUT4 was in band p13. A common two-allele restriction-fragment–length polymorphism (RFLP) was identified with Kpn I, and linkage of this RFLP to other polymorphic DNA markers in this region of chromosome 17 provides a set of probes that will be useful for examining the role of this gene in the pathogenesis of diabetes mellitus.
Type II Diabetes Mellitus and Polymorphism of Insulin-Receptor Gene in Mexican Americans
Authors: Raboudi Soufia H , Mitchell Braxton D , Stern Michael P , Eifler Clayton W , Haffner Steven M , Hazuda Helen P , Frazier Marsha L
Published: September 2013

Resistance to insulin action is a well-established feature of type II (non-insulin-dependent) diabetes and is believed by many to contribute to the etiology of this condition. We therefore characterized restriction-fragment–length polymorphisms of the insulin-receptor gene with the restriction enzyme Rsa I in 242 Mexican Americans and non-Hispanic Whites with type II diabetes and 202 age-, sex-, and ethnicity-matched control subjects who participated in a population-based study in San Antonio. Alleles of 6.7 kilobases (kb) (A allele), 6.2 kb (B allele), and 3.4 kb (C allele) were identified. The C allele was observed in Mexican Americans only, where its frequency among nondiabetic control subjects was 17.7%. Diabetic Mexican Americans were twice as likely as control subjects to be homozygous for the C allele. The crude odds ratio for diabetes in CC homozygotes compared with the other two genotypes was 2.22, although this result was not statistically significant (x2 = 1.57, P = .21). The Mantel-Haenszel odds ratio, adjusting for age, however, indicated a 4.71-fold increased risk of diabetes among Mexican Americans with the CC genotype compared with Mexican Americans without this genotype (X2M-H = 5.38, P = .020). The age of onset of diabetes was also slightly younger in CC homozygote cases (45.4 ± 9.2 yr) than in CX or XX cases (47.7 ± 9.0 and 48.6 ± 9.6 yr, respectively), although this difference was not statistically significant (P .467). The C allele may be involved directly in the etiology of type II diabetes, or it may be in linkage disequilibrium with a functionally significant region of the insulin receptor gene.
Decreased Activation Rate of Insulin-Stimulated Glucose Transport in Adipocytes From Obese Subjects
Authors: Molina Joseph M , Ciaraldi Theodore P , Brady David , Olefsky Jerrold M
Published: September 2013

Recent studies from our laboratory have shown that the rate at which insulin activates glucose disposal in vivo is much slower in obese subjects compared with lean controls. To determine if this was caused by an abnormality in activation of insulin-stimulated glucose transport at the cellular level, we measured the rate at which insulin stimulated glucose transport in human adipocytes from obese volunteers. Basal rates of 3-O-methylglucose transport in the absence of insulin were lower (0.20 ± 0.04 vs. 0.40 ± 0.11 pmol · 10−5 cells · 10 s−1 P <.25) in adipocytes from obese subjects (n = 10) than in lean control subjects (n = 5), but this did not achieve statistical significance. Maximal insulin-stimulated (4300 pM insulin) glucose transport rates were significantly decreased in obesity (2.81 ± 0.81 vs. 1.15 ± 0.20 pmol · 10−5 cells · 10 S−1 P < .005). It took longer for adipocytes from obese subjects to achieve half-maximal activation of insulin-stimulated glucose transport than those from lean subjects (15 ± 2 vs. 9.4 ± 1.2 min, P< .05). The slower overall rates of activation of maximal insulin-stimulated glucose transport observed in adipocytes from obese subjects mirror the slower rates of stimulation of glucose disposal in vivo, which suggests that the in vivo findings are caused by a cellular abnormality in insulin action at a step beyond the binding of insulin to its receptor. The decreased maximal rates of glucose uptake plus the slower rates of activation demonstrated in these studies combine to form an even greater degree of insulin resistance than might be expected from static measurements alone.
Effect of Galactose and Glucose Levels and Sorbinil Treatment on myo-Inositol Metabolism and Na+-K+ Pump Activity in Cultured Neuroblastoma Cells
Authors: Yorek Mark A , Dunlap Joyce A , Leeney Ellen M
Published: September 2013

Neuroblastoma cells were used to analyze the effect of galactose supplementation on myo-inositol metabolism, polyol accumulation, and Na+-K+ pump activity. Culturing cells in 30 mM galactose for a minimum of 1 wk led to a large accumulation of intracellular galactitol and a >50% decrease in myo-inositol content. The effect of galactose on the intracellular content of galactitol and myo-inositol was concentration dependent. Extracellular myo-inositol accumulation and incorporation into phospholipid decreased by 20–30% in cells grown in 30 mM galactose. The decrease in myo-inositol accumulation is apparently due to a noncompetitive inhibition of high-affinity myo-inositol uptake. Treatment of the galactose-containing media with 0.4 mM sorbinil partially prevented the galactose-mediated decreases in myo-inositol metabolism and content. The galactitol content of the sorbinil-treated cells was significantly reduced compared with the galactitol levels in cells cultured in 30 mM galactose; however, galactitol levels remained significantly elevated over control cells. Exposing neuroblastoma cells to 30 mM galactose causes a decrease in the levels of phosphatidylinositol that is partially restored by the addition of sorbinil. The activity of the Na+-K+ pump was decreased by 20% in cells cultured in 30 mM galactose and was partially protected by sorbinil treatment. The effects of long-term galactose supplementation on myo-inositol metabolism, polyol accumulation, and Na+-K+-ATPase transport activity in cultured neuroblastoma cells are similar to the effects of high concentrations of glucose. These results provide additional evidence that the accumulation of polyol by neuroblastoma cells is partially responsible for alterations in myo-inositol metabolism and decreases in Na+-K+-ATPase transport activity
Contribution of Partial Pancreatectomy, Systemic Hormone Delivery, and Duct Obliteration to Glucose Regulation in Canine Pancreas: Importance in Pancreas Transplantation
Authors: Burg Michael P M Van Der , Gooszen Hein G , Guicherit Onno R , Jansen Jan B M J , Frölich Marijke , Haastert Frans A Van , Lamers Cornelis B H W
Published: September 2013

Our aim was to isolate and determine the contribution of partial pancreatectomy, systemic delivery of pancreatic hormones, and duct obliteration to glucose regulation after segmental pancreas transplantation in dogs. Fasting, postprandial, and intravenous glucose-stimulated glucose, insulin, glucagon, pancreatic polypeptide (PP), and cholecystokinin (CCK) and intravenous bombesin-stimulated PP levels were studied in beagles at three successive intervals in a crossover design. The first was 6 wk after partial (∼70%) pancreatectomy with intact regular enteric exocrine drainage from the duodenal pancreatic remnant, the next was 2 wk after venous transposition with systemic delivery of pancreatic hormones, and the third was 6 wk after in situ duct obliteration of the remnant. With partial pancreatectomy, K values were modestly diminished (30%), and a concomitant reduction of second-phase intravenous glucose-stimulated insulin release was observed. Other parameters were not significantly affected. Venous transposition doubled peripheral plasma levels of insulin under all conditions. Fasting glucose, PP, and CCK levels decreased slightly. Other parameters were not affected. Duct obliteration of the systemic draining pancreatic remnants seriously impaired glucose sensitivity, resulting in a 50% reduction of K values and fasting and sustained postprandial hyperglycemia (∼8 mM) and a 70–50% reduction (acute and overall responses, respectively) of intravenous glucose-stimulated insulin. Fasting hormone and postprandial insulin, glucagon, and CCK levels were not affected. The postprandial PP response was severely reduced, and bombesin-stimulated PP release was abolished by duct obliteration. We conclude that histological changes associated with duct obliteration are the major determinants of glucose regulation in segmental pancreas transplantation. The defective acute insulin response to intravenous glucose is probably secondary to obliteration-induced intrinsic denervation of the islets, as supported by an abolished PP response to bombesin. The difference in the effect of duct obliteration on the insulin response to intravenous glucose and a meal may be related to the postprandial activation of the enteropancreatic axis.
Demonstration of Heterogeneity of Autoantibodies to Insulin Receptors in Type B Insulin Resistance by Isoelectric Focusing
Authors: Tsushima Toshio , Omori Yasue , Murakami Hitomi , Hirata Yukimasa , Shizume Kazuo
Published: September 2013

With isoelectric focusing, we examined heterogeneity of autoantibodies to insulin receptors in serums of two patients with insulin-resistant diabetes and one patient with hypoglycemia. Immunoglobulins were prepared by ammonium sulfate precipitation and ion-exchange chromatography with DEAE-Sepharose and subjected to isoelectric focusing for separation into 30 fractions. The fractions were tested for their ability to inhibit 125I-labeled insulin binding to human placental membranes, immunoprecipitate solubilized insulin receptor cross-linked with 125I-insulin, and mimic or inhibit the action of insulin in rat adipocytes. The results varied among the three patients. In the first patient, inhibition of 125I-insulin-binding activity (IBA) and insulin-receptor-precipitating activity (IPA) were distributed almost identically, but the distribution of insulinlike bioactivity (ILBA) was somewhat different. In the second patient, some fractions exhibited potent IBA without IPA, and these fractions inhibited the action of insulin in rat adipocytes. In the third patient, all of the isoelectric fractions showed IBA without IPA and were insulin antagonists. These observations indicate that some patients have antibodies with pure insulin-antagonist properties and provide further evidence that autoantibodies to insulin receptors are polyclonal and recognize different antigenic sites on insulin-receptor molecules. The findings also suggest that the ability of antibodies to elicit ILBA is linked to the ability to immunoprecipitate 125I-insulin-cross-linked and solubilized receptors, whereas antibodies that only inhibit insulin binding behave as insulin antagonists.
Insulinomimetic Properties of Trace Elements and Characterization of Their In Vivo Mode of Action
Authors: Rossetti Luciano , Giaccari Andrea , Klein-Robbenhaar Eveline , Vogel Leslie R
Published: September 2013

Lithium and vanadate have insulinomimetic actions in vitro. In this study, we examined the in vivo effects of lithium and vanadate on glucose metabolism in diabetic (90% partial pancreatectomy) rats. Four groups of chronically catheterized rats were studied: control, diabetic, diabetic treated with lithium (plasma concn 1.0 ± 0.1 meq/L) and vanadate (0.05 mg/ml in drinking water), and diabetic treated with lithium, vanadate, zinc, and magnesium. Postmeal plasma glucose was increased in diabetic versus control rats (18.7 vs. 7.7 mM, P < 0.01) and was normalized by addition of lithium and vanadate (8 mM) or lithium, vanadate, zinc, and magnesium (7.4 mM). Euglycemic insulin-clamp studies were performed 2 wk posttreatment; insulin-mediated glucose uptake was reduced in diabetic compared with control rats (142 ± 4 vs. 200 ± 5 μmol · kg−1 · min−1 P < 0.01), returned to normal with lithium and vanadate (206 ± 6 μmol · kg−1 · min−1), or increased to supranormal levels with lithium, vanadate, zinc, and magnesium (238 ± 6 μmol · kg−1 · min−1). During the insulin clamp, muscle glycogenic rate was severely impaired in diabetic versus control rats (18 vs. 70 μmol · kg−1 · min−1) and was normalized by lithium and vanadate (91 μmol · kg−1 · min−1) or lithium, vanadate, zinc, and magnesium (93 μmol · kg−1 · min−1). Whole-body glycolytic rate (conversion of [3H]glucose to 3H2O) accounted for 55% of glucose disposal in control (106 ± 5 μmol · kg−1 · min−1), 72% in diabetic (103 ± 3 μmol · kg−1 · min−1), 49% in lithium- and vanadatetreated diabetic (98 ± 4 μmol · kg−1 · min−1), and 56% in lithium-, vanadate-, zinc-, and magnesium-treated diabetic (132 ± 4 μmol · kg−1 ± min−1) rats. We conclude that, in diabetic rats, 1) insulin-mediated glucose disposal is markedly impaired, and this primarily reflects a defect in muscle glycogen synthesis, whereas glycolytic flux is not decreased; 2) combined lithium and vanadate treatment normalizes insulin sensitivity and muscle glycogen synthesis; 3) the addition of zinc and magnesium further improves glucose disposal, primarily by stimulating glycolysis. These results suggest that trace-element therapy, either alone or in combination, may prove effective in the treatment of non-insulin-dependent diabetes in humans.
Genetic Control by I-A Subregion in H-2 Complex of Incidence of Streptozocin-Induced Autoimmune Diabetes in Mice
Authors: Tanaka Shun-Ichi , Nakajima Shigeru , Inoue Shuji , Takamura Yutaro , Aoki Ichiro , Okuda Kenji
Published: September 2013

An experimental autoimmune diabetes in mice characterized by delayed-onset hyperglycemia with lymphocytic infiltrations of the pancreatic islets can be induced by multiple administrations of low doses of streptozocin (STZ). We report on the influence of the MHC (H-2 complex) on this autoimmune diabetes by comparing the susceptibilities of various congenic and recombinant strains with a B10 background. In congenic strains, C57BL/10 (H-2b) and B10.BR (H-2k) mice showed a high incidence of diabetes, whereas B10.D2 (H-2d) and B10.S (H-2S) mice showed a low incidence. Therefore, we suggest that the H-2 complex influences diabetes susceptibility and that both b and k are high-susceptibility alleles, whereas d and s are low-susceptibility alleles. In recombinant strains, those with the same haplotypes on the K E S, and D subregions of the H-2 complex showed undefined (high and low) susceptibilities, indicating that the diabetes-susceptibility genes are located outside these loci. Strains possessing I-Ab or I-Ak gene products (C57BL/10, B10.BR, B10.TL, B10.A, and B10.A(2R)) showed high incidences, whereas strains possessing I-Ad or I-As (B10.D2, B10.S, B10.S(7R), B10.S(9R), and B10.GD) showed low incidences. In addition, administration of anti-1-M monoclonal antibody prevented the manifestation of diabetes in STZadministered mice. Passive transfer of STZadministered T lymphocytes to mice given minute doses of STZ induced significant hyperglycemia. This successful transfer was only observed in H-2–compatible mice. Thus, we conclude that one gene coding for susceptibility to this experimental diabetes was located in the I-A subregion within the H-2 complex.
Effect of Insulin on Oxidation of Intracellularly and Extracellularly Derived Glucose in Patients With NIDDM: Evidence for Primary Defect in Glucose Transport and/or Phosphorylation but Not Oxidation
Authors: Butler Peter C , Kryshak Edward J , Marsh Michael , Rizza Robert A
Published: September 2013

Insulin-stimulated glucose oxidation is decreased in patients with non-insulin-dependent diabetes mellitus (NIDDM). It is not known whether this decrease is due to a primary defect in the oxidative pathway or is secondary to impaired glucose transport and/or phosphorylation. To address this issue, glucose oxidation was measured under steady-state conditions at low (∼270 pmol) and high (∼17 μmol) insulin concentrations in seven patients with NIDDM and seven healthy nondiabetic subjects matched for sex, age, and obesity. Glucose oxidation was measured simultaneously by indirect calorimetry and the isotopedilution technique. Although glucose oxidation and nonoxidative storage were lower (P < 0.05) in diabetic than nondiabetic subjects during the low- and highdose insulin infusions, oxidation of intracellularly derived glucose, estimated by subtracting the rate of oxidation measured isotopically (i.e., glucose oxidation derived from the extracellular space) from that measured by indirect calorimetry (i.e., total glucose oxidation), did not differ in diabetic and nondiabetic subjects during the low-dose insulin infusion (3.3 ± 0.1 vs. 3.0 ± 0.1 μmol · kg−1 · min−1). Both techniques provided identical estimates of glucose oxidation during the high-dose insulin infusion. Impaired oxidation of extracellularly but not intracellularly derived glucose strongly suggests that the cause of decreased glucose oxidation in patients with NIDDM is secondary to impaired glucose transport and/or phosphorylation rather than a primary abnormality in the oxidative pathway.
Inhibition of Hepatic Glucose Production by SDZ 51641
Authors: Young Douglas A , Ho Robert S , Bell Philip A , Cohen Diana K , McIntosh Raymond H , Nadelson Jeffrey , Foley James E
Published: September 2013

The new oral hypoglycemic agent SDZ 51641 was evaluated in nondiabetic rats and a rat model of human non-insulin-dependent diabetes mellitus. Diabetes was induced with a single injection of 37.5 mg/kg streptozocin, and the rats exhibited hyperglycemia in the fed state with normal insulin levels. Treatment of nondiabetic animals with 100 mg/kg SDZ 51641 given orally significantly decreased serum glucose and ketone levels within 4 h without affecting insulin levels. Nonesterified fatty acids increased more than twofold during the same period. Its effect on ketone and fatty acid levels suggests that SDZ 51641 acts as an inhibitor of fatty acid oxidation. Diabetic rats treated with SDZ 51641 exhibited a significant acute hypoglycemic response, which was more pronounced after 3 days of treatment. The compound also significantly decreased serum cholesterol and triglyceride levels 27 and 53%, respectively. When endogenous hepatic glucose production was assessed in nondiabetic and diabetic animals via continuous infusion of [3-3H]glucose, we found that hepatic glucose production was elevated 43% in diabetic compared with control animals. When diabetic rats were treated with 100 mg/kg SDZ 51641, hepatic glucose production decreased to normal levels within 6 h. Hyperinsulinemic-euglycemic clamp studies indicated that SDZ 51641 had no effect on insulinstimulated glucose utilization. Measurement of [1-14C]oleate oxidation in isolated hepatocytes demonstrated that SDZ 51641 inhibited long-chain fatty acid oxidation in a concentration-dependent manner. The compound was ineffective at inhibiting longchain fatty acid oxidation in epitrochlearis or soleus muscles. In summary, SDZ 51641 is a new oral hypoglycemic agent that is very effective in decreasing blood glucose levels in nondiabetic and diabetic rats. This is accomplished at least partially by inhibition of hepatic glucose production in vivo, with no effect on peripheral glucose utilization. In addition, the ability of SDZ 51641 to decrease serum ketone, cholesterol, and triglyceride levels suggests that inhibition of hepatic glucose production is linked to inhibition of fatty acid oxidation.
Insulinlike Activity of New Antidiabetic Agent CP 68722 in 3T3-L1 Adipocytes
Authors: Kreutter David K , Andrews Kim M , Gibbs E Michael , Hutson Nancy J , Stevenson Ralph W
Published: September 2013

We examined the in vitro effects of CP 68722, a novel antidiabetic agent, in 3T3-L1 adipocytes. CP 68722 stimulated 2-deoxyglucose uptake in the absence of insulin. At least 30 min of incubation were required for stimulation of uptake. This effect increased over 5 h and was sustained up to 72 h. The stimulation of 2-deoxyglucose uptake by CP 68722 could be inhibited ∼60% by inhibition of protein synthesis with cycloheximide. Half-maximal and maximal responses to CP 68722 at 72 h of incubation were observed at 10 and 100 μM of drug, respectively, with a threefold stimulation of uptake at 100 μM approximating the maximal response of these cells to acute insulin stimulation. CP 68722 was able to overcome insulin resistance induced by dexamethasone in 3T3-L1 cells. The effect of drug, like that of insulin, was primarily to increase the Vmax of 2-deoxyglucose uptake. The stimulation of uptake by CP 68722 or insulin could be prevented by incubating the cells at 10°C, a temperature that impedes translocation of glucose transporters to the plasma membrane. Therefore, it appears that CP 68722, like insulin, stimulates glucose uptake by a mechanism that involves translocation of intracellular glucose transporters to the plasma membrane and de novo protein synthesis. We compared the effect of CP 68722 with the sulfonylureas, the primary drugs used in the treatment of non-insulin-dependent diabetes mellitus (NIDDM). CP 68722 was a more potent and effective stimulator of 2-deoxyglucose uptake in 3T3-L1 cells than either first- or second-generation sulfonylureas. Our results suggest that CP 68722 could be an effective therapeutic agent for the treatment of NIDDM.