bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-Range Implications for the Mother: The Aberdeen Experience
Authors: Stowers John M , Sutherland Hamish W , Kerridge David F
Published: September 2013

One hundred twelve women with impaired glucose tolerance (IGT) diagnosed by intravenous glucose tolerance test (IVGTT) after pregnancy were followed up for a period of up to 22 yr (mean 12.9 yr). About one-third have been treated with chlorpropamide and the others by diet only. At the final assessment, approximately 35% had abnormal intravenous glucose tolerance and less than 7% overt diabetes. Chlorpropamide did not prove significantly more effective than diet only. Factors associated with deterioration in glucose tolerance were age at diagnosis and follow-up and the initial fasting plasma glucose (FPG) level (≥5.8 mM), but obesity was less important, although it was associated with an increased rate of vascular complications. Tests for islet cell antibodies (ICA) were weakly positive in 12.5% of 72 subjects and in only 0.5% of an unselected population; they did not correlate with the final state of glucose tolerance. Only three patients developed insulindependent diabetes (IDDM) and did so before the ICA study was started. A comparison is made between the results reported by O'Sullivan in patients diagnosed as having gestational diabetes, only 2% of whom still had abnormal oral glucose tolerance postpartum, and the results of our patients, all of whom had IGT after pregnancy. In spite of differences of technique and in the populations studied, the prevalence of IGT and overt diabetes at follow-up was significantly less in the Aberdeen series, who were initially a higher risk group. It seems probable that this is mainly attributable to dietary treatment in the follow-up period as O'Sullivan's cases were treated only during pregnancy.
Is There an Animal Model for Gestational Diabetes?
Authors: Hellerström Claes , Swenne Ingemar , Eriksson Ulf J
Published: September 2013

This article reviews the effects of pregnancy on carbohydrate metabolism and insulin production in the normal rat and discusses some animal models of potential value for the study of gestational diabetes mellitus (GDM). Against the background of current clinical and laboratory experiences it is suggested that GDM reflects a deficiency in islet B-cell proliferation in response to the increased insulin requirement during pregnancy. Although this hypothesis lends itself for testing in animal experiments, a suitable animal model for GDM needs to be described.
Antepartum Fetal Surveillance in Gestational Diabetes Mellitus
Authors: Landon Mark B , Gabbe Steven G
Published: September 2013

Pregnancy in patients with gestational diabetes mellitus (GDM) is associated with increased perinatal morbidity. Whether the perinatal mortality rate, particularly the fetal death rate, is greater in these patients remains controversial. The present study was undertaken to review the role of antepartum fetal monitoring in 69 patients with GDM controlled by diet only (class A) and 28 women requiring insulin therapy (class AB). Hypertension complicated 21.6% of these pregnancies.

Antepartum fetal surveillance included outpatient nonstress testing, urinary estriol assays, maternal assessment of fetal activity, and clinical estimation of fetal weight. All insulin-requiring patients as well as fourteen class A patients with identifiable risk factors underwent testing. No perinatal deaths occurred. Only six patients required intervention for suspected fetal jeopardy and four of these women had hypertension. Macrosomia was correctly identified in only 6 of 16 infants weighing 4000 g or more.

This study suggests that, in GDM, an outpatient program of fetal testing, using primarily the nonstress test and maternal assessment of fetal activity, can be employed in patients requiring insulin as well as class A patients with identifiable risk factors. This protocol resulted in a low rate of unnecessary intervention and good perinatal outcome. The risks for abnormal antepartum testing results appear increased in GDM with hypertension and prolonged pregnancy.
Geographic, Ethnic, and Racial Variations in the Incidence of Gestational Diabetes Mellitus
Authors: Hadden D R
Published: September 2013

The prevalence of diabetes and of gestational diabetes varies considerably between countries and within countries. There are also major national and international differences in the important end points of fetal or neonatal death and congenital fetal abnormality. These differences relate to multiple factors, of which diabetes or gestational diabetes represents only a part of the total pathologic effect.

There is also international disagreement on the most appropriate diagnostic criteria for gestational diabetes. The main uncertainty is whether to adopt the World Health Organization figures, e.g., venous plasma glucose 2 h after 75 g glucose ≥ 140 mg/dl (8.0 mmol/L) as gestational impaired glucose tolerance, and ≥200 mg/dl (11.0 mmol/L) as gestational diabetes, or to use the Boston figures, e.g., venous plasma glucose 2 h after 100 g glucose ≥ 165 mg/dl (9.5 mmol/L) as gestational diabetes. It is hoped that standards for pathologic hyperglycemia in pregnancy can be agreed on for use in all countries for all populations.
Reversal of D- and A-Cell Insensitivity to Glucose in Alloxan-diabetic Dogs by Treatment with the Artificial Beta Cell (Biostator)
Authors: Hermansen K , Schmitz O , Ørskov H
Published: September 2013

Insulin-deficient diabetes in man as well as in experimental diabetes is associated with islet cell insensitivity to glucose. The present study was designed to determine whether this abnormality could be counteracted either by increasing the intraislet insulin level or by normalizing the diabetic state by a glucose-controlled insulin infusion system (GCIIS: Biostator, Life Science Instruments, Elkhart, Indiana). Using the isolated, perfused pancreas of dogs with moderate, untreated alloxan diabetes of 4 days duration, we found that 5 mM arginine (N = 4) and 5 mM calcium (N = 4) stimulated D- and A-cell secretion, whereas an increment in glucose from 1.3 to 11 mM (N = 4) had no effect on islet hormone secretion. In the pancreas from untreated alloxan-diabetic dogs, acute infusion of large amounts of insulin (25 mU/ml) in vitro simultaneously with an elevation of perfusate glucose from 1.3 to 11 mM failed to restore the glucose sensitivity. In contrast, treatment of alloxan-diabetic dogs (N = 3) by a GCIIS for 24 h revived some responsiveness of the glucagon, insulin, and somatostatin to glucose (1.3–11 mM) of the subsequently perfused pancreas. It is concluded that the insensitivity to glucose of islet cells in insulin-deficient diabetes is not ascribed to an intra-islet insulin deficiency per se but rather to an abnormal metabolic state secondary to insulin deficiency. The results also indicate that the glucose receptor dysfunction is not due to a direct lesion by the diabetogenic drug.
The Metabolic Clearance of Insulin and the Feedback Inhibition of Insulin Secretion Are Altered with Aging
Authors: Fink R I , Revers R R , Kolterman O G , Olefsky J M
Published: September 2013

Elevated basal and stimulated insulin levels have been previously demonstrated in elderly human subjects. To see whether these elevated insulin levels are due to alterations in either the metabolic clearance rate (MCR) for insulin or the feedback inhibition of insulin secretion, we have studied 14 elderly and 19 nonelderly subjects, mean age 70 ± 2 and 35 ± 2 yr, respectively. Fasting serum insulin and C-peptide levels were elevated in the elderly compared with the nonelderly, 17 ± 2 versus 11 ± 1 μU/ml, P < 0.01 and 0.95 ± 0.12 versus 0.47 ± 0.07 pmol/ml, P < 0.001. Euglycemic hyperinsulinemia created by insulin infusion rates of 15, 40, and 1200 mU/m2/min with glucose held constant resulted in steady-state serum insulin levels of 65 ± 4, 109 ± 8, and 11,316 ± 890 versus 34 ± 2, 96 ± 5, and 11,083 ± 1079 μU/ml in the elderly and nonelderly subjects, respectively. The MCR of insulin was decreased by 46% in the elderly compared with the nonelderly (10.1 ± 0.7 versus 18.7 ±1.4 ml/kg/min) at the insulin infusion rate of 15 mU/m2/min with no difference observed between the two groups at the higher insulin infusions. Steady-state suppression of C-peptide by exogenous insulin was similar, 73 ± 2% versus 72 ± 2% and 70 ± 3% versus 64 ± 5% in the nonelderly and elderly groups during the 15 and 40 mU/m2/min insulin infusions, respectively. However, 50% suppression was achieved within 30 min in the nonelderly group compared with 70 min in the elderly group during the low-dose infusion. While the maximal percent C-peptide suppression was comparable for the nonelderly and elderly, absolute C-peptide levels were increased at all times in the elderly during both infusions. In elderly subjects, a significant inverse relationship (r = −0.81, P < 0.01) was observed between the MCR of insulin and the total insulin response during a 7-h meal tolerance test. In summary, (1) aging is associated with a decrease in the MCR of insulin at low physiologic insulin levels. At higher serum levels, this effect is blunted, possibly due to a decreased role of hepatic uptake as a primary removal mechanism. (2) The decreased clearance rate of insulin and a defect in feedback inhibition of insulin secretion may also contribute to the hyperinsulinemia associated with aging.
Effect of E-Series Prostaglandins on Cyclic AMP-dependent and -independent Hormone-stimulated Glycogenolysis in Hepatocytes
Authors: Brass Eric P , Garrity Maureen J
Published: September 2013

The effect of E-series prostaglandins (PGE) on hormone-stimulated glycogenolysis was studied in isolated rat hepatocytes. As previously reported, the physiologically active analogue 16,16-dimethyl-PGE2 inhibited glucagon-stimulated glycogenolysis. This effect could be reproduced by repetitive addition of PGE2 to compensate for PGE2 catabolism. In contrast, glycogenolysis stimulated by N6,O2′-dibutyryladenosine-3/5′-cyclic monophosphate (dibutyryl-cAMP) was unaffected by either PGE2 or 16,16-dimethyl-PGE2 (rate of glycogenolysis with 0.34 μM dibutyryl-cAMP plus 1.7 (μM 16,16-dimethyl-PGE2 = 99 ± 6% of rate with 0.34 μM dibutyryl-cAMP alone; mean ± SEM, N = 5). Similarly, glycogenolysis stimulated by 8-bromoadenosine-3′,5′-cyclic monophosphate was not inhibited by PGE2 or 16,16-dimethyl-PGE2.

Epinephrine-stimulated glycogenolysis was inhibited by 16,16-dimethyl-PGE2 in a dose-dependent manner. PGE inhibited the cAMP-independent stimulation of glycogenolysis resulting from phenylephrine or angiotensin II exposure (rate of glycogenolysis with 8 μM phenylephrine + 1.7 μM 16,16-dimethyl-PGE2 = 65 ± 10% of rate with 8 μM phenylephrine alone, N = 4, P < 0.05; 4.9 μM angiotensin 11 + 1.7 μM 16,16-dimethyl-PGE2 = 75 ± 7% of rate with 4.9 μM angiotensin II alone, N = 4, P < 0.05). Glycogenolysis stimulated by the calcium ionophore A23187 was also inhibited by PGE (rate of glycogenolysis with 0.55 μg/mlA23187 + 1.7μM16,16-dimethyl-PGE2 = 83 ± 5% of rate with 0.55 μg/ml A23187 alone, N = 7, P < 0.05).

Thus, PGE can inhibit both cAMP-dependent and cAMP-independent hormone-stimulated glycogenolysis. The results suggest two sites of inhibition, one consistent with inhibition of adenylate cyclase stimulation and a second inhibiting calcium-mediated stimulation at an undefined site.
Assay for Islet Cell Antibodies: Protein A—Monoclonal Antibody Method
Authors: Srikanta S , Rabizadeh A , Omar M A K , Eisenbarth G S
Published: September 2013

Assays for islet cell antibodies (ICA) are finding increasing application in clinical diabetology. We have developed a new islet cell antibody assay system (ICA-pA), whose salient features include: (1) utilization of fluorescein-conjugated staphylococcal protein A as a standard second-step reagent, the advantages of this approach being improved “signal” (islet)/“noise” (acini) ratio due to reduction of interfering background acinar pancreatic staining, and facilitation of assay standardization provided by the use of a chemically pure conjugated protein A reagent; (2) monoclonal antibody counterstaining with rhodamine-conjugated BISL-32 for the rapid identification of islets in pancreatic sections; and (3) quantitation of circulating serum ICA by microimmunofluorometric techniques.
Prevention of Kidney Graft Diabetic Nephropathy by Pancreas Transplantation in Man
Authors: Bohman S -O , Tydén G , Wilczek H , Lundgren G , Jaremko G , Gunnarsson R , Östman J , Groth C G
Published: September 2013

Kidney graft biopsies were performed 2–3 yr after transplantation in eight type I (insulin-dependent) diabetic patients who had previously been subjected to kidney transplantation (six patients) or combined kidney and segmental pancreas transplantation (two patients). In five of the six patients that had undergone only kidney transplantation, light microscopic examination of the graft biopsy revealed changes compatible with diabetic nephropathy, and electron microscopic morphometry showed a thickening of the glomerular basement membrane (GBM). In the two patients who had been subjected to combined pancreas and kidney transplantation, the kidney graft biopsy showed no light microscopic changes suggestive of diabetic nephropathy, and electron microscopy showed no thickening of the GBM. Thus, it appears to be possible to prevent the recurrence of diabetic nephropathy in human kidney allografts by simultaneous pancreas transplantation.
Studies of Retinopathy: Methodology for Assessment and Classification with Fundus Photographs
Authors: Davis Matthew D , Hubbard Larry D , Trautman James , Klein Ronald ,   The Kroc Collaborative Study Group
Published: September 2013

A major goal of the study was to assess the methodologies available for the quantification of retinal lesions suitable for application in trials of metabolic management. We describe the methods used for grading stereoscopic color fundus photographs. Overall retinopathy severity level for each eye ranging from normal (level 10) to high-risk category (level 70) was assigned on the basis of gradings of individual lesions. Change in retinopathy severity level over the 8-mo period was detected in 3–62% of patients, depending on the method used and the definition of change. Lesions responsible for change in level were mainly retinal infarcts (soft exudates) and intraretinal microvascular abnormalities.
Assessment of Fluorescein Angiograms
Authors: Kohner E M , Lawson P M , Ghosh G , Testa M ,   The Kroc Collaborative Study Group
Published: September 2013

Quantitation of the earliest changes in abnormal retinal morphology using fluorescein angiography is potentially superior to retinal photography. However, the critical importance of flawless technique, limitations in the size of the field available for detailed study, and observer variability constitute major disadvantages. A protocol describing standards of photography and of injection was developed. Methodology for counting microaneurysms (Ma) was developed at a central laboratory and applied in suitable photographs obtained at 0 (baseline), 4, and 8 mo in 68 patients. Counts of “definite” or “possible” Ma were made on films projected under standard conditions by two observers known to achieve consistently reproducible results. Semiquantitative assessment of diffusibility of fluorescein reflecting capillary leakage was performed in 61 patients. Leakage was graded according to three degrees of severity permitting study of observer variation, concordance of change in pairs of eyes, and treatment effects.

The average number of Ma at baseline was slightly higher in the continuous subcutaneous insulin infusion (CSII) group than in the conventional insulin treatment (CIT) group, but the difference was not statistically significant at the 0.05 level. At both 4 and 8 mo, definite Ma were more prevalent in the CSII group, and the difference was statistically significant at the 0.05 level using both parametric and nonparametric tests. In 27 CSII and 23 CIT patients having complete sets of 0, 4, and 8-mo photographs, Ma counts increased during the 0–4–mo interval. During the 4–8-mo interval, a further increase occurred in the CSII group but contrasted with a decrement observed in the CIT group, which showed no net change from baseline. Stratification of baseline data showed no influence of differing baseline Ma counts on these changes. Reproducible quantitation of fluorescein leakage was accomplished by one of three observers. In the CSII group, increased leakage was statistically significant in the right eyes only during the 0–8-mo interval (P < 0.05).

These data suggest that CSII does not benefit and may produce deterioration in early diabetic retinopathy during 8 mo of treatment. The relatively slower rate of progression of the CIT group could not be explained on the basis of increasing nonperfusion with consequent poor filling of Ma. Nevertheless, changes in hemodynamic factors may explain these changes, which suggest short-term deterioration of early diabetic retinopathy. Whether this response is protracted will be apparent from long-term studies of effects of nearnormoglycemia.
Clinical Predictors of Retinopathy and Its Progression in Patients with Type I Diabetes During CSII or Conventional Insulin Treatment
Authors: Testa Marcia A , Puklin James E , Sherwin Robert S , Simonson Donald C ,   The Kroc Collaborative Study Group
Published: September 2013

Data from 70 type I diabetic patients with nonproliferative retinopathy participating in a multicenter clinical trial of control and complications were analyzed to test for associations of clinical variables with baseline levels and 8-mo changes in retinopathy. Predictor variables included age, duration of diabetes, systolic blood pressure, inpatient and outpatient plasma glucose levels, glycosylated hemoglobin (HbA1), M-values, serum cholesterol, serum triglycerides, and creatinine clearance. Retinopathy was assessed by fundus photography and graded at the Fundus Photograph Reading Center according to a detailed protocol. For the entire group, baseline retinopathy was positively correlated (P < 0.05) with baseline systolic blood pressure, plasma glucose, HbA1, serum cholesterol, and duration of disease and negatively correlated with creatinine clearance. Conversely, during treatment, progression of retinopathy was negatively correlated (P < 0.05) with mean levels during treatment of plasma glucose, HbA1, M-values, serum cholesterol, and with changes during treatment in plasma glucose and serum triglycerides. Two-group and three-group multivariate classification analysis of progression of retinopathy (improved or unchanged versus worsening—mild or moderate) indicated lower plasma glucose as the single best predictor of worsening of retinopathy (P < 0.05), correctly classifying 71% of patients with positive progression. Decreased creatinine clearance during therapy was found to be the best discriminator between mild and moderate progression. Other multivariate models yielded specificity values of up to 71% and sensitivity values of up to 92%.

We conclude that associations among clinical predictors and retinopathy during short-term glycemic control differ strikingly from those at baseline. Furthermore, results from the classification analysis suggest that the progression of retinopathy is influenced by a complex interaction of clinical variables, rather than by glycemic control alone.
Insulin Secretion in Mammosomatotropic Tumor-bearing and Pregnant Rats: A Role for Lactogens
Authors: Sorenson Robert L , Parsons Jonathan A
Published: September 2013

The experiments reported here investigate the effects of two conditions of elevated lactogen activity on the threshold of glucose stimulation of insulin secretion and suprathreshold, glucose-stimulated insulin secretion in the isolated, perfused rat pancreas. In both the tumor-bearing animals and pregnant animals, the glucose threshold for insulin release was markedly reduced and the suprathreshold insulin release was elevated over that observed in control pancreata. There was no change on the glucose threshold or extent of release of somatostatin secretion. Altered insulin secretion appears to be readily reversible, since the secretion profile from postlactating animals was not different from the controls. The possible mechanistic role of lactogens is discussed.
Effects of Anti-insulin Receptor Antibodies on In Vivo Insulin Metabolism
Authors: Boden Guenther , Shimoyama Ryushi , Ray Tarun K , Savage Richard C
Published: September 2013

The effects of anti-insulin receptor antibodies (AIRA) on receptor binding and insulin metabolism were studied in two patients with the type B, severe insulin resistance syndrome. Insulin binding was determined using rat hepatocytes in primary culture and the patient's own red blood cells. Plasma and urinary insulin concentrations and metabolic clearance rates (MCR) were determined in the two patients and in four normal controls in response to infusions of insulin for 60–120 min at rates ranging from 1 to 925 mU/kg/min. In patient 1, basal insulin concentration was 1400 μU/ml. After infusion of 1, 10, and 925 mU/kg/min of insulin it rose to 3800, 5500, and 225,000 μU/ml, respectively. Respective MCRs were 19, 110, and 186 ml/min. In patient 2, basal insulin concentration was 440 μU/ml. After infusion of 1, 10, and 100 mU/kg/min of insulin it rose to 720, 2500, and 18,800 μU/ml, respectively. Respective MCRs were 193, 262, and 294 ml/min. In controls, basal insulin concentration was 4 ± 0.3 μU/ml. After infusion of 1 and 10 mU/kg/min of insulin, it rose to 82 ± 17 and 1288 ± 50 μU/ml. Respective MCRs were 950 and 630 ml/min. These data showed that, in patients with AIRA: (1) insulin metabolism took place at the same rate but at higher insulin concentrations than in normal controls, and (2) MCR increased with rising insulin concentration but remained subnormal even at the highest insulin concentrations. In contrast, MCR in normal controls decreased with increasing insulin concentrations.

The data suggest that prevention of insulin binding prevents insulin metabolism at physiologic insulin concentrations and that supraphysiologically elevated insulin concentrations are needed to activate nonreceptor mechanisms.
Glucose-induced Increases in Renal Hemodynamic Function: Possible Modulation by Renal Prostaglandins
Authors: Kasiske Bertram L , O'donnell Michael P , Keane William F
Published: September 2013

Increased glomerular filtration rate and kidney size early in the course of experimental and human diabetes may be important in the pathogenesis of diabetic nephropathy. Factors causing these renal functional changes are unknown. The isolated, perfused rat kidney (IPRK) was used to study the effects of elevated glucose levels on kidneys from normal and diabetic rats in the absence of complex systemic effects of in vivo hyperglycemia. It was found that acute increases in perfusate glucose levels caused sustained dosedependent vasodilatation in both normal and diabetic isolated kidneys. Furthermore, in normal kidneys, raising perfusate glucose to levels seen in moderately severe diabetes caused increased inulin clearance (CIn). In contrast, equal osmolar concentrations of mannitol caused sustained vasoconstriction and a slight decrease in CIn. Prostaglandin synthetase inhibitors reduced glucose-induced vasodilatation by 50% and prevented the increase in CIn that followed the addition of glucose to normal kidneys. Thus, these studies demonstrated that elevated glucose levels caused significant vasodilatation and increased CIn in the IPRK, and these glucose-induced hemodynamic changes were attenuated by prostaglandin synthetase inhibitors. It is possible that these glucose-induced effects may be important determinants of increased glomerular function in early diabetes.
Rapid Effects of Insulin on the Cycling of the Insulin Receptor in a Human Monocyte Cell Line (U-937)
Authors: Livingston James N , Saran Bruce R , Rose Cheryl D , Anderson Clark L
Published: September 2013

The insulin receptor and its regulation by insulin was studied in U-937 monocytes, a human cell line with properties similar to those of normal peripheraf blood monocytes. Treatment of this cell with insulin for 8–16 h produced an overall loss in the insulin receptor, i.e., a loss of receptors from the cell surface and internal pools. In contrast, short-term insulin treatment (15–30 min) caused a reduction in cell surface receptors but an increase in the internal receptors, as judged by pronase treatment at 4°C to distinguish receptor location. After the removal of insulin and pronase, the internalized receptors were rapidly reinserted back into the cell surface after warming to 37°C.

Further studies showed an insulin-mediated increase in fluid-phase pinocytosis as measured by horseradish peroxidase (HRP) uptake. The amount of HRP accumulation and the time course for this stimulation were similar to those for receptor internalization. These features plus other results suggest that the insulin-stimulated internalization of insulin receptors may require an acceleration in the rate of pinocytic vesicle formation.
Insulin Suppresses Rat Growth Hormone Messenger Ribonucleic Acid Levels in Rat Pituitary Tumor Cells
Authors: Melmed Shlomo , Neilson Lorna , Slanina Susan
Published: September 2013

Insulin has been shown to suppress growth hormone (GH) secretion by rat pituitary tumor cells (GH3) independently of glucose utilization. The effects of physiologic doses of insulin were therefore tested on cytoplasmic levels of GH messenger ribonucleic acid (mRNA) sequences. Insulin (3.5 nM) treatment of cells for 5 days suppressed the hybridization of cytoplasmic GH mRNA with 32P-cDNA for rGH by 50%. The three- to fourfold induction of cytoplasmic GH mRNA by hydrocortisone (1 μM) was also suppressed by insulin (3.5 nM) by 40%. The results show a direct suppression of cytoplasmic rGH mRNA concentration by physiologic doses of insulin. These findings may be due to either decreased rate of GH gene transcription, increased intracellular breakdown, or decreased nuclear-cytoplasmic transport of GH mRNA caused by insulin.
Regulation of Ketogenesis by Epinephrine and Norepinephrine in the Overnight-fasted, Conscious Dog
Authors: Steiner Kurt E , Fuchs Howard , Williams Phillip E , Stevenson Ralph W , Cherrington Alan D , Alberti K G M M
Published: September 2013

The effects on ketogenesis and lipolysis of a norepinephrine (0.04 μg/kg-min), epinephrine (0.04 μg/kg-min), or saline infusion were examined in the overnight-fasted, conscious dog. Plasma insulin and glucagon levels were maintained constant by means of a somatostatin infusion (0.8 μg/kg-min) and intraportal replacement infusions of insulin and glucagon. In saline-infused dogs, plasma epinephrine (62 ± 8 pg/ml), norepinephrine (92 ± 29 pg/ml), blood glycerol (87 ± 10μM), and plasma nonesterified fatty acid (NEFA) (0.82 ± 0.17 mM) levels did not change. Total blood ketone body levels tended to rise (62 ± 10 to 83 ± 11 μM) by 3 h as did total ketone body production (1.5 ± 0.4 to 2.2 ± 0.4 (μmol/kg-min) over the same time interval. Norepinephrine infusion to produce plasma levels of 447 ± 86 pg/ml caused a sustained 50% rise in glycerol levels (66 ± 17 to 99 ± 15 μmol/L, P < 0.05) and 53% rise in nonesterified fatty acids (0.53 ± 0.07 to 0.81 ± 0.15 μmol/L, P < 0.05). Total ketone body levels rose by 43% (51 ± 8 to 73 ± 10 μmol/L) and ketone body production rose by a similar proportion (1.5 ± 0.2 to 2.2 ± 0.3 μmol/kg-min), changes that did not differ significantly from control animals. A similar increment in plasma epinephrine levels (75 ± 15 to 475 ± 60 pg/ml) caused glycerol levels to rise by 82% (105 ± 23 to 191 ± 26 (μmol/L) in 30 min, but this rise was not sustained and the level fell to 146 ± 14 (μmol/L by 120 min. Plasma nonesterified fatty acids rose from a basal value of 0.89 ± 0.19 mM to 1.25 ± 0.29 mM during the first 30 min, but fell to 0.60 ± 0.12 mM by 2 h. Ketone body levels remained unchanged (66 ± 10 μmol/L) and ketone body production declined (1.5 ± 0.3 to 1.0 ± 0.2 μmol/kgmin). These data indicate that (1) although the sustained increase in lipolysis caused by norepinephrine was greater than that caused by fasting alone, the ketogenic responses were not different, and (2) epinephrine has a transient lipolytic effect and an antiketogenic effect compared with controls.
Normalization by Sodium Salicylate of the Impaired Counterregulatory Glucagon Response to Hypoglycemia in Insulin-dependent Diabetes: A Possible Role for Endogenous Prostaglandins
Authors: Giugliano Dario , Giannetti Giovanni , Pinto Paolo Di , Cerciello Teresa , Ceriello Antonio , D'Onofrio Felice
Published: September 2013

The present study was undertaken to evaluate the influence of sodium salicylate on the counterregulatory glucagon response to insulin-induced hypoglycemia in both insulin-dependent diabetic subjects (IDDM) and normal controls. The IDDM group consisted of 5 patients with recent onset of disease (<45 days), a normal glucagon response to hypoglycemia, and no detectable insulin antibodies (group 1); and 7 patients with duration of disease between 1 and 5 yr, a reduced glucagon response to hypoglycemia, and no insulin antibodies (group 2). Ten healthy subjects served as a control group. The infusion of sodium salicylate (40 mg/min) during insulin-induced hypoglycemia (1 mil/kg-min for 60 min) in normal subjects caused a significant increase of thecounterregulatory glucagon response both in terms of glucagon peak and integrated areas. Sodium salicylate itself significantly increased basal insulin and decreased glucose, but did not change basal glucagon. In the diabetic subjects of group 1, sodium salicylate amplified the glucagon response to the same degree of hypoglycemia without affecting the rates of glucose fall and recovery. Compared with normals and diabetic subjects of group 1, diabetic subjects of group 2 presented,in basal conditions, a reduced glucagon response to hypoglycemia and a slower rate of glucose recovery. Sodium salicylate normalized both defects. These results indicate that sodium salicylate may augment glucagon responses by improving the recognition of hypoglycemia in both normals and IDDM. Moreover, the restoration by sodium salicylate of a normal glucagon response to hypoglycemia in diabetic subjects of group 2 suggests a role for endogenous prostaglandins in this selective deficiency of the counterregulatory response.
Effect of Sodium 2-Chloropropionate on Glucagon Secretion in the Rat
Authors: Ribes G , Valette G , Dalstein J M , Loubatieres-Mariani M M
Published: September 2013

We have previously shown that, in alloxan-diabetic dogs, the adjunction of sodium 2-chloropropionate (2-CP) with insulin injections resulted in a reduction of both hyperglycemia andhyperglucagonemia. The present studies were designed to more closely examine the glucagon-lowering effect of 2-CP. We investigated whether 2-CP was able to reduce elevated glucagon secretion both in vivo in streptozocin (STZ)-diabetic rats, and in vitro in the isolated, perfused rat pancreas. 2-CP (1 mmol/kg or 108 mg/kg) was given during 2 mo through esophageal tube to diabetic rats deprived of exogenous insulin. The drug induced a significant reduction of hyperglucagonemia (P < 0.05) of blood lactate and alanine levels (P < 0.02) and of plasma triglyceride levels (P < 0.001). Furthermore, 2-CP markedly decreased glucosuria (P < 0.005). In the isolated rat pancreas perfused with 2.8 mmol/L glucose, the continuous perfusion of 2-CP (1 mmol/L) starting before an infusion of arginine or alanine (5 mmol/L) considerably reduced the hypersecretion of glucagon evoked by these amino acids (P < 0.001). These experiments show that sodium 2-chloropropionate can reduce glucagon hypersecretion in the diabetic rat not only in vivo, but acts also directly in vitro on the isolated, perfused pancreas Of normal rats.
Decreased Biologic Activity and Degradation of Human [SerB24]-Insulin, a Second Mutant Insulin
Authors: Haneda Masakazu , Kobayashi Masashi , Maegawa Hiroshi , Watanabe Nobuaki , Takata Yasumitsu , Ishibashi Osamu , Shigeta Yukio , Inouye Ken
Published: September 2013

A second mutant insulin, identified as [SerB24]-insulin, has a highly hydrophilic character. To determine the biologic activity and the degradation of this mutant insulin, human [SerB24]- and [SerB25]-insulin analogues were semisynthesized from porcine insulin by an enzyme-assisted coupling method. All of the following studies on isolated rat adipocytes were performed at 37°C to directly correlate the binding potency and the biologic activity. The ability of these insulins to displace 125I-porcine insulin bound to adipocytes was 0.5–2% and 1–4%, respectively, of porcine insulin. When the ability of these insulins to stimulate glucose transport and glucose oxidation was measured, both analogues had full activity at high concentrations (250 ng/ml). However, ED50 of the porcine, [SerB24]-, and [SerB25]-insulins tostimulate glucose transport was 0.37 ± 0.05, 46.3 ± 5.4, and 23.3 ± 5.5 ng/ml, respectively. Similarly, for glucose oxidation, ED50 was 0.38 ± 0.06, 33.8 ± 3.6, and 16.6 ± 3.4 ng/ml, respectively. Thus, the biologic activity of [SerB24]- and [SerB25]-insulins was reduced to 0.5–2% and 1–4% of that of porcine insulin, which was compatible with our previous studies under different conditions. No antagonistic effects were observed for either analogue. Degradation of 125I-labeled [SerB24]- and [SerB25]-insulins was also decreased to 62.8% and 55.8%, respectively, of 125I-porcine insulin. These results confirm the importance of the hydrophobic residues at B24 and B25 in the biologic activity of insulin; the patient having this hydrophilic insulin was considered to be in an insulinopenic state despite the hyperinsulinemia due to decreased degradation of the mutant insulin.
Dynamics of Glucose-induced Insulin Release During the Spontaneous Remission of Streptozocin Diabetes Induced in the Newborn Rat
Authors: Portha Bernard , Kergoat Micheline
Published: September 2013

Neonatal rats injected with streptozocin (STZ, 100 mg/kg) at birth exhibited an acute diabetes followed by a spontaneous remission. We have previously shown that this recovery from neonatal diabetes is due to B-cell regeneration and reaccumulation of pancreatic insulin stores starting from 3 to 5 days after birth. The B-cell population during this period is heterogeneous with both surviving B-cells that have escaped the toxic effect of STZ and newly formed B-cells. To evaluate to what extent this B-cell population is functionally normal, we have measured in vitro the dynamics of glucose-induced insulin secretion from pancreatic fragments of rats treated with STZ at birth. The insulin responses were tested at intervals after STZ treatment, from day 1 to day 21 using perifusion of pancreatic fragments, and on day 21 and at 5 mo using perfusion of isolated pancreas.

While the glucose-induced insulin release was completely obtunded (2% of the normal response)on day 1 after STZ, it could be demonstrated after day 3. Moreover, it increased as a function of age (6% and 36% of the normal responses on day 5 and day 14, respectively). This restoration of the insulin response to glucose closely paralleled the recovery of pancreatic insulin stores (6% and 51% of normal values, respectively, on day 5 and day 14). In sharp contrast with the lack of glucose response in vitro in the adult, glucose-induced insulin release was still detected on day21 regardless of the in vitro system used (perifusion or perfusion). Furthermore, on day 21 the B-cells of the STZ rats exhibited a tendency toward enhanced insulin response to arginine, which is a prominent feature in adult rats previously treated with STZ at birth.

The present observations make it unlikely that STZ treatment per se causes a chronic loss of the glucosesensitive insulin secretion mechanism in the surviving B-cells or in the newly formed B-cells. Moreover, as we have previously shown that in adult rats given a neonatal STZ treatment the B-cells exhibit a selective insensitivity to glucose in vivo, the present data support the notion that the pathogenesis of this lesion is caused by factors other than a primary toxic effect of STZ.
Lymphoid Cells of BB/W Diabetic Rats Are Cytotoxic to Islet Beta Cells In Vitro
Authors: MacKay Peter , Boulton Andrew , Rabinovitch Alexander
Published: September 2013

Assays were developed to detect cell-mediated immune destruction of pancreatic islet beta cells by lymphoid cells isolated from diabetic BioBreeding/Worcester (BB/W) rats. Splenic lymphoid cells from diabetic (D), diabetes-prone (DP), and diabetes-resistant (DR) BB/W rats were incubated for 2 days with monolayer cultures of major histocompatibility complex (MHC)-compatible Wistar-Furth (WF) rat islet cells or a rat islet cell line (RIN), and islet beta cell survival was determined by measuring insulin content in the cultures. D splenic lymphoid cells significantly decreased insulin content in WF rat islet (−32%) and RIN cultures (−77%). DP cells also significantly reduced the insulin content in WF rat islet (−20%) and RIN cultures (−63%), whereas DR cells had no significant effect. Islet-directed cytotoxicity was detected also by the release of 51Cr from RIN cells incubated for 8 h with BB/W spleen cells. Cytotoxicity was linearly related to the number of effector spleen cells. At a target:effector of 1:20, lysis (mean ± SEM) of RIN target cells by spleen cells from D rats (21.6 ± 2.0%) and DP rats (16.5 ± 4.1%) was significantly greater than the effect of DR spleen cells (5.4 ± 1.0%). D and DP splenic lymphoid cells activated in vitro for 2 days with concanavalin A exhibited a doubling of cytotoxicity to RIN islet cells. These results provide direct evidence for lymphoid cell-mediated immune damage to islet beta cells in diabetic BB rats.
Regulation of Gluconeogenesis in Hepatocytes from Fasted Alloxan-diabetic Rats
Authors: Wernette-Hammond Mary Ellen , Lardy Henry A
Published: September 2013

Hepatocytes from fasted, alloxan-diabetic rats were ipcubated in the absence of gluconeogenic substrates to deplete residual glycogen stores. Glucose production from lactate and pyruvate was enhanced in cells from diabetic rats relative to similarly treated hepatocytes from fasted, nondiabetic control rats. Gluconeogenesis from dihydroxyacetone, fructose, or glycerol was not increased but the formation of lactate plus pyruvate from dihydroxyacetone was decreased.

The stimulation of gluconeogenesis by exogenous fatty acids was decreased by diabetes. The rates of gluconeogenesis in the presence of lactate plus pyruvate plus oleate were equal in hepatocytes from diabetic and control rats and indicate that the maximal rate of gluconeogenesis was not increased.

With lactate plus pyruvate as substrates, stimulation of gluconeogenesis by norepinephrine or dibutyrylcAMP was not altered by diabetes. The catecholamine stimulation of gluconeogenesis from glycerol also was unaffected. In contrast, diabetes decreased the maximal stimulation of gluconeogenesis from dihydroxyacetone by dibutyryl-cAMP, glucagon, or norepinephrine and this decrease was proportional to the decreased production of lactate plus pyruvate. The concentrations of glucagon or norepinephrine required for half-maximal stimulation were not altered by diabetes. Thus, the hormonal stimulation of gluconeogenesis from dihydroxyacetone is decreased by diabetes, probably because of decreased pyruvate kinase activity, but the interaction of glucagon and norepinephrine with hepatocytes and the subsequent stimulation of gluconeogenesis from physiologic substrates is not impaired.
Effect of Norepinephrine on Ketogenesis, Fatty Acid Oxidation, and Esterification in Isolated Rat Hepatocytes
Authors: Oberhaensli Rolf D , Schwendimann Rita , Keller Ulrich
Published: September 2013

Recent studies in man demonstrated a marked ketogenic effect of increased plasma norepinephrine concentrations as observed in diabetic ketoacidosis. Since this effect may have been due either to increased substrate supply for ketogenesis (lipolysis) or to direct hepatic activation of ketogenesis, the latter mechanism was examined in isolated rat hepatocytes. Incubation of hepatocytes with norepinephrine (10−7 to 10−4 M) resulted in a dose-dependent increase in conversion of the long-chain fatty acid [1−14C]palmitate into ketone bodies and CO2. Norepinephrine decreased [1-14C]palmitate conversion into triglycerides without affecting fatty acid uptake.

Norepinephrine enhanced ketogenesis from [1-14C]palmitate in a physiologic range of fatty acid concentrations (0.5–2.5 mM), but failed to affect fatty acid esterification to phospholipids or mono- and diglycerides. In contrast to long-chain fatty acids, oxidation of the medium-chain fatty acid [1-14C]octanoate to ketone bodies was not enhanced by norepinephrine, whereas CO2 production increased. The effect of norepinephrine on [1-14C]fatty acid oxidation was blocked by the a, receptor blocker prazosine. The results demonstrate that norepinephrine diverts long-chain fatty acids into the pathways of oxidation and ketogenesis away from esterification, suggesting enhanced carnitine-dependent mitochondrial fatty acid uptake. The studies using octanoate indicated that norepinephrine also enhanced fatty acid oxidation by increasing the flux of acetyl-CoA through the Krebs cycle.

The data suggest that stress-associated sympathetic activation and norepinephrine discharge, as observed in diabetic ketoacidosis, result in direct activation of ketogenesis in the liver.
U.K. Prospective Diabetes Study: II. Reduction in HbA1c with Basal Insulin Supplement, Sulfonylurea, or Biguanide Therapy in Maturity-onset Diabetes
Authors:   A Multicenter Study
Published: September 2013

Newly presenting maturity-onset diabetic subjects were put on diet and if, after 3–4 mo, their fasting plasma glucose continued >6 mmol/L, they were randomized to three therapies: (1) continuing diet alone, (2) with additional sulfonylurea, or (3) with additional basal insulin supplement provided by ultralente insulin. Obese patients were also randomized to metformin therapy. The aim was to lower the fasting plasma glucose to <6 mmol/L and the degree to which this reduced the hemoglobin A1c (HbA1c) concentration was studied in 195 patients over 1 yr. Sulfonylurea and insulin similarly reduced (P < 0.001) the fasting plasma glucose from 8.3 ± 1.9 to 6.7 ±1.3 mmol/L (mean ± 1 SD) and 8.6 ± 2.2 to 6.8 ±1.4 mmol/L, respectively. This was accompanied by a significant reduction (P < 0.001) of the HbA1c to the high normal range, from 9.1 ± 2.1% to 7.8 ± 1.2%, and from 9.1 ± 1.9% to 8.1 ± 1.3%, respectively, both values at 1 yr being significantly (P < 0.05) lower than in patients randomized to diet alone. Patients randomized to diet alone had little change in fasting plasma glucose (8.6 ± 1.8 to 9.3 ± 2.3 mmol/L) or HbA1c (8.8 ± 1.7% to 9.1 ± 1.6%, respectively). Thus, the simple therapeutic aim of trying to reduce the fasting plasma glucose to <6 mmol/L is an effective means of reducing the HbA1c to a high-normal level. The HbA1c and fasting plasma glucose concentrations were similarly related for all three therapies (HbA1c [%] = 0.47 × fasting plasma glucose [mmol/L] + 4.7). If the fasting plasma glucose concentration after dieting was >10 mmol/L, maximal-dose sulfonylurea therapy rarely reduced the fasting plasma glucose to 6 mmol/L and such patients could be started on maximum sulfonylurea therapy. Similar patients randomized to a basal insulin supplement alone required high insulin doses (mean 25 U/day), and also had mean fasting plasma glucose and HbA1c levels above the normal range.
Plasma and Skeletal Muscle Free Amino Acids in Type I, Insulin-treated Diabetic Subjects
Authors: Borghi Loris , Lugari Roberta , Montanari Alberto , Dall'Argine Paola , Elia Gian F , Nicolotti Vincenza , Simoni Isabella , Parmeggiani Alessandra , Novarini Almerico , Gnudi Angelo
Published: September 2013

Insulin-dependent diabetes mellitus (IDDM) induces plasma amino acid (AA) abnormalities, including low alanine and high branched-chain (BCAA). While insulin treatment restores plasma AA pattern, proline, methionine, valine, isoleucine, and total BCAA remain elevated in skeletal muscle intracellular water. This suggests that the restoration of plasma AA concentrations is not a satisfactory index of recovered AA metabolism in IDDM.
Cytotoxic Islet Cell Surface Antibodies (ICSA) in Patients with Type I Diabetes and Their First-degree Relatives
Authors: Toguchi Yayoi , Ginsberg-Fellner Fredda , Rubinstein Pablo
Published: September 2013

We describe a nonradioactive microcytotoxicity assay for ICSA using a cloned rat insulinoma cell line. This assay system had good reproducibility (r = 0.93) and was suitable for the study of large numbers of samples. The following results were obtained by testing the sera of 111 patients with IDDM (type I diabetes) and all of their first-degree relatives. (1) Thirty-five percent of IDDM patients had ICSA, as compared with only 2% of healthy controls. (2) ICSA was found more frequently in patients within 2 yr of onset (45%) than in those with disease for longer than 2 yr (27%) (P < 0.05). (3) The prevalence of ICSA was associated with the presence of cytoplasmic islet cell antibodies (ICA) (P < 0.05). (4) No association was found between the prevalence of ICSA and specific HLA-DR aileles. Association with the HLA haplotypes in families with ICSA-positive probands, on the other hand, is suggested although not proven by these data. (5) Among the nondiabetic relatives of IDDM patients, 5% of the parents and 14% of the sibs had ICSA. Increased prevalence of ICSA occurred in the unaffected sibs of ICSA-positive probands (31%) but not in those of ICSA-negative probands (4%) (P < 0.001); in fact, therelatives of ICSA-negative probands had ICSA with a frequency not higher than in unrelated controls. (6) Female relatives of ICSA-positive probands were more often ICSA-positive than males, but no such difference was found among probands. (7) In multiplex sibships, ICSA were not associated with disease in the sibs. These results suggest that the persistent presence of ICSA in relativesof IDDM patients is determined by a combination of environmental and genetic factors, including sex.