Glucose tolerance and insulin response in parents of patients with insulin-dependent and juvenile-onset non-insulin-dependent diabetes mellitus.

Glucose tolerance and insulin response were examined using a 100 g oral glucose tolerance test (OGTT) in 108 parents of 23 patients with insulin-dependent (IDDM) and 31 patients with non-insulin-dependent diabetes mellitus (NIDDM), whose age of onset of diabetes was less than 35 years. Thirty-two age-matched healthy volunteers without a family history of diabetes were also examined as a control group. Diabetes and impaired glucose tolerance (IGT) were significantly more frequent in parents of NIDDM (diabetes 34%, IGT 27%) than in parents of IDDM (diabetes 7%, IGT 13%) (P less than 0.001). At least one parent had diabetes or IGT in 30% of IDDM and 84% of NIDDM patients (P less than 0.001), and both parents had diabetes or IGT in 9% of IDDM and 39% of NIDDM patients (P less than 0.02). Even in cases with 'normal' glucose tolerance, the mean plasma glucose was higher in parents of NIDDM than in control subjects, suggesting a high prevalence of abnormal glucose tolerance including the marginal degree of abnormality in the families of NIDDM. The early phase insulin response was decreased more among parents of NIDDM with the greater impairment of glucose tolerance. However, among those with 'normal' glucose tolerance, early phase insulin response did not differ between parents of IDDM and NIDDM, and control subjects. The results confirmed a stronger familial background in NIDDM patients of younger onset than in IDDM. The different patterns of glucose tolerance among two parents of young-onset NIDDM patients suggest heterogeneity of the mode of inheritance of NIDDM among families.     

Urinary C-peptide as an index of unstable glycemic control in insulin-dependent diabetes mellitus (IDDM)

In order to investigate whether urinary C-peptide (UCP) excretion can be a useful index of insulin-dependent diabetes mellitus (IDDM) with unstable glycemic control, UCP was measured in nine IDDM patients with unstable glycemic control, nine IDDM patients with stable glycemic control, and 12 non-insulin-dependent diabetic (NIDDM) patients treated with insulin. The UCPs in overnight urine (U1) and fasting single void urine (U2) in IDDM patients with unstable glycemic control were significantly lower than those in IDDM patients with stable glycemic control (U1: 0.03 +/- 0.03 vs 0.24 +/- 0.20 nmol/mmol-Creatinine, U2: 0.02 +/- 0.01 vs 0.20 +/- 0.20 nmol/mmol-Cr, mean +/- SD, both P less than 0.01). The UCPs in U1 and U2 in both groups of IDDM were significantly lower than those in NIDDM (U1: 0.97 +/- 0.52, U2: 0.73 +/- 0.41 nmol/mmol-Cr, both P less than 0.01). The UCPs in U1 and U2 significantly correlated with incremental C-peptide response to intravenous glucagon injection and with glycemic stability assessed by the standard deviation of 10 previous fasting plasma glucose levels. These results suggest that UCP reflects their residual insulin secretory capacity and that UCP can be a useful index which distinguishes patients with unstable IDDM from those with stable diabetes mellitus.     

Insulin binding to circulating monocytes in children with insulin-dependent and non-insulin-dependent diabetes mellitus

This study describes insulin binding to circulating monocytes in 24 children with insulin-dependent diabetes mellitus (IDDM), five children with non-insulin-dependent diabetes mellitus (NIDDM), and 10 healthy and 12 obese control children. Insulin binding to monocytes was greatly increased in untreated IDDM children with obvious ketoacidosis (5.51 +/- 3.49 vs. 1.91 +/- 0.47 pg/10(6) cells, P less than 0.01), whereas it was decreased in those without obvious ketoacidosis (1.39 +/- 0.30 vs. 1.91 +/- 0.47 pg/10(6) cells, P less than 0.01). Insulin treatment restored insulin binding almost to the level of control children in both ketoacidotic and non-ketoacidotic patients. Insulin binding to monocytes was markedly decreased in untreated NIDDM children with hyperinsulinemia compared with healthy control children (0.73 +/- 0.27 vs. 1.91 +/- 0.47 pg/10(6) cells, P less than 0.01) or obese control children (0.73 +/- 0.27 vs. 1.33 +/- 0.35 pg/10(6) cells, P less than 0.01). These data indicate that changes in insulin secretion and metabolic conditions might be involved in the fluctuation of the number of insulin receptors in IDDM children as well as in NIDDM children.     

Serum insulin-like growth factor I levels in adult diabetic patients: the effect of age

Despite reports of reduced serum insulin-like growth factor (IGF) levels in experimentally diabetic animals, human diabetic patients have been reported to have decreased, normal, or even elevated levels. This study was a cross-sectional examination of the effect of age on immunoreactive IGF-I levels in adult patients with insulin-dependent or noninsulin-dependent diabetes mellitus (IDDM and NIDDM) attending a diabetes out-patient clinic. The patients and normal subjects studied were divided into the age ranges 21-30, 31-40, 41-50, 51-60, and over 60 yr. For all ages combined, the mean IGF-I level (+/- SD) was 0.84 +/- 0.26 U/ml (202 +/- 62 ng/ml) in 133 normal subjects, significantly reduced to 0.41 +/- 0.17 U/ml in 121 IDDM patients, and 0.49 +/- 0.19 U/ml in 46 NIDDM patients (both P less than 0.001). In both groups there was a marked decline in IGF-I with increasing age (P less than 0.01). Except for NIDDM patients aged 21-30 yr (only two patients), IGF-I levels in both IDDM and NIDDM patients were significantly lower in every age range than those in age-matched normal subjects, but did not differ between the two diabetic groups. Glycosylated hemoglobin levels correlated inversely with IGF-I levels only in younger patients with IDDM (r = -0.486; P less than 0.05 for patients aged 21-40 yr). We conclude that factors common to IDDM and NIDDM, perhaps related to relative nutritional deficiency at the cellular level, cause a reduction in serum IGF-I levels, and that this reduction occurs independently of age-related changes in IGF-I.     

Glucose tolerance behaviour before the onset of type I (insulin-dependent) diabetes in young people as a predictor of the further course of the disease: a retrospective analysis of 33 cases

A study was made of glucose tolerance and insulin secretion in 33 persons who later developed insulin-dependent diabetes (aged 4-24 years) and observation continued further in the first years after manifestation. Patients who developed the typical labile type of diabetes were of normal weight and had either normal glucose tolerance tests before diagnosis or had impaired glucose tolerance (IGT) for a short interval of 2-16 months. Subjects with IGT over a significantly (p less than 0.01) longer period of 32.30 +/- 6.25 (normal body weight) or 94.71 +/- 20.62 (obese) months developed a milder form of diabetes with retarded insulin dependency in obese subjects. The severe and mild form of IDDM are distinct with respect to insulin requirement (0.75 +/- 0.03 or 0.28 +/- 0.04 U/kg b.w., P less than 0.01) and glucagon stimulated C-peptide (0.18 +/- 0.05 or 1.41 +/- 0.27, P less than 0.01) in the first 2.5-3.5 years after onset. The two forms were not different regarding HLA-DR antigens. Islet cell surface antibodies investigated in 15 probands at 27 occasions before diabetes onset had no prognostic value. The development of a mild form of IDDM may be expected in cases with pre-existing IGT for more than one year. The insulin secretion is of low predictive value under these conditions. The observation is of practical use and theoretical interest.     

Quantification of the relative impairment in actions of insulin on hepatic glucose production and peripheral glucose uptake in non-insulin-dependent diabetes mellitus

In non-insulin-dependent diabetes mellitus (NIDDM), both liver and peripheral tissues are resistant to insulin, but the relative severity and contribution of these abnormalities to fasting hyperglycemia are poorly understood. We, therefore, determined the dose-response characteristics for insulin-mediated suppression of hepatic glucose production (GP) and stimulation of peripheral glucose uptake (GU) in 14 NIDDM subjects and 14 age- and weight-matched nondiabetic volunteers (NV) using the glucose clamp sequential insulin infusion technique along with isotopic estimation of glucose flux. Postabsorptive rates of both GP (94 +/- 7 v 72 +/- 2 mg/M2/min in NV, P less than .01) and GU (88 +/- 5 v 72 +/- 2 in NV, P less than .01) were significantly increased in NIDDM subjects. The ED50 (half-maximally effective plasma insulin concentration) in NIDDM subjects for suppression of GP (64 +/- 14 microU/mL) and stimulation of GU (118 +/- 20 microU/mL were both increased more than twofold above normal (26 +/- 2 and 58 +/- 5 microU/mL, respectively, both P less than .01) and were significantly correlated with one another (r = .68, P less than .01). Although GP could be totally suppressed in the NIDDM subjects, their maximal GU was reduced 30% (287 +/- 20 v 372 +/- 15 mg/m2/min in NV, P less than .01). Nevertheless, at all physiologically relevant plasma insulin concentrations studied, there was comparable impairment in GP and GU responses. Moreover, fasting plasma glucose concentrations in NIDDM subjects were highly correlated with their increased basal rates of GP (r = .81, P less than .005) but not with their reduced GU.(ABSTRACT TRUNCATED AT 250 WORDS)     

Can insulin resistance exist as a primary defect in noninsulin-dependent diabetes mellitus?

In this study we have attempted to quantify the plasma insulin response to glucose and insulin action in 22 nonobese subjects: 11 with normal glucose tolerance and 11 with mild [mean fasting plasma glucose concentration, 128 +/- (+/- SEM) 5 mg/dL] noninsulin-dependent diabetes mellitus (NIDDM). Estimates of the plasma insulin response were made by determining the plasma insulin concentration at hourly intervals from 0800-1600 h, before and after mixed meals consumed at 0800 h (breakfast) and 1200 h (lunch). Insulin action was assessed by measuring glucose uptake during insulin clamp studies performed at steady state plasma insulin levels of approximately 10 and 60 microU/mL, with the difference between the 2 values defined as insulin-stimulated glucose uptake. Plasma glucose (P less than 0.001) and insulin (P less than 0.001) concentrations were significantly higher in patients with NIDDM throughout the 8-h period (by two-way analysis of variance). However, mean (+/- SEM) insulin-stimulated glucose uptake was markedly reduced (P less than 0.001) in patients with type 2 diabetes mellitus (112 +/- 72 vs. 336 +/- 44 mg/m2 min-1). Thus, patients with NIDDM and mild fasting hyperglycemia were both insulin resistant and hyperinsulinemic compared to normal individuals. These data indicate that a defect in insulin-stimulated glucose uptake can occur in NIDDM in the absence of significant hyperglycemia and/or hypoinsulinemia.     

Effect of insulin antibodies and their kinetic characteristics on plasma free insulin dynamics in patients with diabetes mellitus

To determine the influence of insulin antibodies (and their equilibrium kinetic properties) on the pharmacokinetics of insulin, we examined the relationship between insulin antibody binding and the initial rate of increase, time to peak, and return to baseline of therapeutic doses of insulin injected subcutaneously (0.15 U/kg) and the half-life, distribution space, and metabolic clearance rate of intravenously infused insulin (2 mU/kg/min) in insulin-treated patients with diabetes mellitus. Compared to age-weight-matched nondiabetic subjects, the diabetic subjects had reduced initial rates of increase (0.33 +/- 0.2 v 0.44 +/- 0.03 microU/mL/min, P less than 0.05), delayed time to peak (130 +/- 12 v 86 +/- 8 min, p less than 0.02), and prolonged return to baseline (485 +/- 37 v 313 +/- 13 min, P less than 0.01) of plasma free insulin levels after subcutaneous injection of insulin, and a prolonged half-life (19.8 +/- 5.8 v 4.3 +/- 0.3 min, P less than 0.02), increased distribution space (904 +/- 284 v 109 +/- 10 mL/kg, P less than 0.001), and augmented metabolic clearance rate (28.5 +/- 1.8 v 17.3 +/- 0.7 mL/kg/min, P less than 0.001) after intravenously infused insulin. All of these abnormal parameters were significantly correlated with binding of insulin to insulin antibodies at tracer insulin concentrations (Bo) and with the high affinity of insulin antibody binding sites as determined by Scatchard analysis. However, patients with 125I insulin antibody binding (Bo) less than 10 percent had normal or near normal plasma free insulin pharmacokinetics.(ABSTRACT TRUNCATED AT 250 WORDS)     

Non-insulin-dependent diabetes and renal replacement therapy

Reports of renal replacement therapy in diabetes usually refer to patients with insulin-dependent diabetes mellitus (IDDM) only, and little is known about renal failure in non-insulin-dependent diabetics (NIDDM). A high proportion, 46/141 (32%), of the diabetics treated at our unit since 1974 had NIDDM. They were older at treatment (56 +/- 9 years, mean +/- SD) compared to the IDDM patients (39 +/- 10 years, p less than 0.001), and had a shorter duration of diabetes (13 +/- 8 years versus 23 +/- 8 years, p less than 0.001). Asians and Afro-Caribbeans accounted for 48% of the NIDDM patients (22/46) compared to only 7% of those having IDDM (6/95, p less than 0.0001). Non-diabetic renal disease accounted for the renal failure in 32% (15/46) of the NIDDM patients but only in 10.5% (10/95) of the IDDMs (p less than 0.001). Despite these differences the prevalence of other diabetic complications (retinopathy, neuropathy, and cardiovascular disease) was similar. Patient survival after transplantation was poorer in NIDDM than IDDM (23% and 57%, respectively, at 2 years). Survival on dialysis was equally poor in NIDDM and IDDM. Thus, NIDDM patients treated for renal failure are more commonly non-European and more often have non-diabetic renal disease. Yet other diabetic complications occur to the same extent in both IDDM and NIDDM patients with diabetic nephropathy.     

A comparison of serum C-peptide response to intravenous glucagon, and urine C-peptide, as indexes of insulin dependence

Serum C-peptide (SCPR) at fasting and after intravenous injection of glucagon was evaluated in diabetic patients with various degrees of insulin dependence, and compared with 24 h urine C-peptide (UCPR). Fasting SCPR did not differ between healthy subjects and sulfonylurea-treated patients (SU) who were considered to have definite non-insulin-dependent diabetes (NIDDM); but was significantly lower in patients with insulin-dependent diabetes (IDDM) (0.24 +/- 0.10 ng/ml in IDDM vs. 1.43 +/- 0.61 ng/ml in SU, P less than 0.001). SCPR reached a peak at 6 min after glucagon injection, except for the IDDM group. The SCPR response at 6 min after 1 mg glucagon injection was significantly lower in the SU (NIDDM) group than in the normal group (2.86 +/- 1.21 v. 4.69 +/- 1.47 ng/ml, P less than 0.001). In the IDDM group, there was no increase of SCPR after glucagon injection. Among diabetic patients, SCPR response to glucagon correlated positively to the amounts of UCPR (P less than 0.001). By analysis of the distribution patterns of SCPR response to intravenous glucagon, SCPR of 1.0 ng/ml and the increment of SCPR of 0.5 ng/ml at 6 min are to be used as cut-off points to differentiate IDDM and NIDDM. These values correspond roughly to the UCPR values below 20 micrograms/day and above 30 micrograms/day, which we previously proposed as indexes to differentiate insulin-dependent and non-insulin-dependent diabetes.     

Insulin receptor function and glycogen synthase activity in skeletal muscle biopsies from patients with insulin-dependent diabetes mellitus: effects of physical training

This study was designed to examine the mechanisms causing peripheral insulin resistance in patients with insulin-dependent diabetes mellitus (IDDM) by studying insulin receptor function and glycogen synthase activity in biopsies of skeletal muscle. The results in seven such patients were compared with values obtained in a group of sedentary, age- and sex-matched normal subjects. In addition, since physical training appears to improve insulin sensitivity, the IDDM patients were reexamined after physical training for 6 weeks. The mean maximal glycogen synthase activity was lower in the diabetic than in the normal group [34.5 +/- 10.6 (+/- SD) vs. 45.7 +/- 8.6 nmol/mg protein.min; P less than 0.05], whereas there was no difference in the half-maximal activation constant (A0.5) for glucose-6-phosphate. Likewise, the mean yield of wheat germ agglutinin-purified insulin receptors recovered per mg muscle was 21% lower in the muscle biopsies from the diabetic patients (47 +/- 8 vs. 66 +/- 20 fmol/100 mg; P less than 0.05. However, basal and insulin-stimulated receptor kinase activities, expressed as phosphorylation of the synthetic peptide poly-Glu-Tyr(4:1), were identical in the two groups. After physical training in the diabetic patients the mean maximal oxygen uptake increased from 45.7 +/- 7.4 to 48.9 +/- 9.0 mL O2/kg.min (P less than 0.05), hemoglobin A1c decreased from 7.9 +/- 1.4% to 7.7 +/- 1.5% (P less than 0.05), and insulin requirements decreased from 43 +/- 9 to 38 +/- 8 U/day (P less than 0.05). The number of recovered insulin receptors did not increase, and the receptor kinase activity was similar to the pre-training value. Maximal glycogen synthase activity increased by 15% (P less than 0.02), whereas A0.5 for glucose-6-phosphate did not change. We conclude that insulin binding to muscle-derived insulin receptors is impaired in IDDM patients, whereas receptor kinase function appears to be normal. The capacity for glycogen storage in the diabetic skeletal muscle was reduced. Physical training tended to normalize glycogen synthase activity, but did not improve insulin receptor function significantly.     

Nutritional profile of fibrocalculous pancreatic diabetes and primary forms of diabetes seen in southern India

Plasma levels of retinol binding protein (RBP), prealbumin, total protein, albumin, transferrin and ferritin were estimated in three groups of diabetic patients seen at a diabetes centre in S. India. The groups consisted of patients with fibrocalculous pancreatic diabetes (FCPD), non-insulin-dependent diabetes mellitus (NIDDM) and insulin-dependent diabetes mellitus (IDDM). Mean RBP levels were lower in FCPD and IDDM patients compared to controls but this did not reach statistical significance. Prealbumin levels were normal in FCPD patients, but low in IDDM compared to controls (P less than 0.005) and NIDDM (P less than 0.05). FCPD patients had lower transferrin levels compared to controls (P less than 0.05). There were no differences in the levels of total protein, albumin and ferritin in any of the study groups. The study shows that biochemical evidence of undernutrition is seen in FCPD and IDDM patients while NIDDM patients are not significantly different from non-diabetic control subjects.     

Insulin action kinetics in adipocytes from obese and noninsulin-dependent diabetes mellitus subjects: identification of multiple cellular defects in glucose transport

Recent results from in vivo studies have shown that the kinetics of insulin action are impaired in lean and obese noninsulin-dependent diabetes mellitus (NIDDM) subjects as well as in obese nondiabetic subjects. We have measured the onset and loss of insulin action on glucose transport in adipocytes obtained from obese nondiabetic and obese NIDDM subjects to determine the contributions of obesity and diabetes to these cellular defects in insulin action. Basal and maximally insulin-stimulated rates of 3-O-methylglucose transport in adipocytes from obese and obese NIDDM subjects were reduced to 50% of the values in cells from normal subjects (P less than 0.05). The activation of glucose transport by insulin (4.3 nmol/L) was slower in cells from obese NIDDM patients. Half of the maximal insulin effect (A50) was reached by 23.0 +/- 5.0 min compared to 9.4 +/- 1.1 min in normal cells (P less than 0.05). Conversely, the deactivation of insulin-stimulated glucose transport upon removal of insulin was more rapid in adipocytes from the obese and obese NIDDM subjects. Half of the maximal insulin effect (D50) was lost by 12.4 +/- 1.7 min in obese NIDDM cells and by 8.9 +/- 1.9 min in obese subjects compared to 25.3 +/- 1.9 min in adipocytes from normal subjects (P less than 0.01). In conclusion, 1) basal and insulin-stimulated rates of glucose transport are similarly reduced in adipocytes from obese and obese NIDDM subjects; and 2) adipocytes from obese and obese NIDDM subjects display defects in the kinetics of insulin action, slower activation and accelerated deactivation, that mirror the defects measured in vivo. Both impairments in the kinetics of insulin action may contribute to the insulin resistance in these subject groups.     

Insulin regulates the 35 kDa IGF binding protein in patients with diabetes mellitus

The serum levels of the low molecular form of insulin-like growth factor binding protein (IGFBP) was determined in 56 outpatients with diabetes mellitus by a radioimmunoassay developed for amniotic 35 kDa IGFBP. The mean level of 35 kDa IGFBP was found to be threefold higher in insulin dependent diabetes mellitus (IDDM), 112 +/- 13 ng/ml, than in age matched controls, 37 +/- 2 ng/ml, while the mean level in non-insulin dependent diabetes mellitus (NIDDM), 16 +/- 2 ng/ml, was decreased. In hospitalized IDDM patients there was a significant correlation (r = 0.91, p less than 0.01) between fasting blood-glucose and 35 kDa IGFBP levels, not found in NIDDM patients. During insulin infusion the 35 kDa IGFBP levels declined with a half-life of 60-120 min. The decline in IGFBP continued even after the establishment of steady state B-glucose at 4.7 mmol/l. In conclusion, the elevated 35 kDa IGFBP levels in IDDM can be attributed to insulin deficiency and may reflect a reduced bioavailability of the IGFs at the target cells.     

Relationship between endothelin-1 concentration and metabolic alterations typical of the insulin resistance syndrome

The purpose of the study was to examine the relationship between the endothelin-1 (ET-1) concentration and the metabolic variables characteristic of the insulin resistance syndrome ([IRS] hyperinsulinemia, insulin resistance, hypertriglyceridemia, low high-density lipoprotein [HDL] cholesterol, visceral obesity, and glycemic abnormalities). The measurement of circulating ET-1 is a well-recognized marker of endothelial atherosclerotic and cardiovascular disease. Two hundred subjects were divided into 3 groups. Group 1 included 50 subjects with impaired glucose tolerance (IGT) or non-insulin-dependent diabetes mellitus (NIDDM) with IRS. Group 2 included 50 subjects with IGT or NIDDM without IRS. Group 3 included 100 normal subjects as controls. ET-1 levels were higher in group 1 versus groups 2 and 3 in women (11.2 +/- 0.7 v 7.9 +/- 0.5 and 6.6 +/- 0.4 pg/mL, P < .01) and men (10.1 +/- 0.6 v 6.5 +/- 0.8 and 7.2 +/- 0.3 pg/mL, P < .01). No differences were found between groups 2 and 3. With simple regression analysis, ET-1 levels significantly correlated with insulin, glycosylated hemoglobin, body weight, waist to hip ratio, and triglyceride values. However, with multiple regression analysis, only triglycerides (P < .009) and glycosylated hemoglobin (P < .001) remained independently correlated with ET-1. In conclusion, this cross-sectional study indicates that glycosylated hemoglobin and triglycerides are independently correlated with ET-1 levels in patients with IRS.     

Disproportionately elevated proinsulin in Pima Indians with noninsulin-dependent diabetes mellitus

Fasting serum total immunoreactive insulin (IRI), true insulin, and true proinsulin (PI) were measured in 169 Pima Indians. The relationship of these variables to glucose tolerance, obesity, and parental diabetes was studied. Seventy-seven subjects had normal glucose tolerance, 46 had impaired glucose tolerance (IGT), and 46 had noninsulin-dependent diabetes mellitus (NIDDM) by WHO criteria. In subjects with normal glucose tolerance, the geometric mean ratio of PI to IRI (PI/IRI) was 10.8% (arithmetic mean, 12.5%), similar to that reported in other ethnic groups with lower prevalence rates of NIDDM. Parental diabetes had no effect on PI/IRI. Obese persons (body mass index, greater than or equal to 27 kg/m2) with normal glucose tolerance had PI/IRI of 9.3% compared with 16.3% for the nonobese (P less than 0.001), and PI/IRI was negatively correlated with body mass index (r = -0.34; P = 0.002). Proinsulin was disproportionately elevated in NIDDM (geometric mean PI/IRI, 19.9%; arithmetic mean, 23.6%), and the degree of elevation was related to the severity of hyperglycemia, but not the duration of diabetes. Subjects with IGT were more obese and had higher fasting plasma glucose (5.7 vs. 5.2 mmol/L; P = 0.025), true insulin (250 vs. 125 pmol/L; P less than 0.001), and PI concentrations (26 vs. 15 pmol/L; P less than 0.001) than those with normal glucose tolerance but similar mean PI/IRI (9.4 vs. 10.8%; P = 0.4). These findings indicate that Pima Indians with NIDDM have a disproportionate elevation of PI consistent with the hypothesis that beta-cell dysfunction associated with hyperglycemia leads to the release of proinsulin-rich immature granules.     

C-peptide secretion in calcific tropical pancreatic diabetes

Serum C-peptide levels were measured during a glucagon stimulation test in ten normal nonobese controls and 54 diabetic patients with recent onset of diabetes under 30 years of age. Diabetic patients were comprised of 13 CTPD, 23 IDDM, and 18 NIDDM. As similar to IDDM patients, serum C-peptide concentrations did not rise significantly (P greater than 0.05) in response to glucagon administration in CTPD-patients. Mean baseline and peak serum C-peptide concentrations in CTPD-patients were significantly lower (P less than 0.001) than the values in normal controls and NIDDM patients, but were significantly higher (P less than 0.05) than those in IDDM patients. We conclude that CTPD patients have partial C-peptide reserve, which may protect against ketosis and contribute to ketosis resistance in CTPD. Our results also suggest that CTPD patients require insulin treatment. Neither baseline nor peak C-peptide levels after glucagon could discriminate CTPD from IDDM and CTPD from NIDDM.     

Soluble P-selectin and CD40L levels in subjects with prediabetes, diabetes mellitus, and metabolic syndrome--the Chennai Urban Rural Epidemiology Study

The aim of the study was to determine whether the levels of soluble P-selectin (sP-selectin) and soluble CD40L (sCD40L) are elevated in Asian Indian subjects with impaired glucose tolerance (IGT), diabetes, and metabolic syndrome (MS). Study subjects were recruited from the Chennai Urban Rural Epidemiology Study (CURES), an ongoing population-based study on a representative population of Chennai city in southern India, and were grouped as follows: group 1, normal glucose tolerance (NGT) (n = 60); group 2, IGT (n = 60); and group 3, type 2 diabetes mellitus (n = 60). Normal glucose tolerance, IGT, and diabetes were defined using World Health Organization consulting group criteria. The inclusion criteria were nonsmokers; normal resting 12-lead electrocardiogram; absence of angina, myocardial infarction, or history of any known vascular, infectious, or inflammatory diseases; and subjects not on statins or aspirin. Insulin resistance was calculated using the homeostasis assessment model using the formula: fasting insulin (microIU/mL) x fasting glucose (mmol/L)/22.5. Soluble P-selectin and sCD40L were estimated by enzyme-linked immunosorbent assay. Metabolic syndrome was defined using Adult Treatment Panel III guidelines. Subjects with diabetes and IGT were older (diabetes: 53 +/- 9 years, P < .01; IGT: 51 +/- 10 years, P < .05) compared with the NGT group (48 +/- 10 years). Subjects with diabetes and IGT had higher levels of sP-selectin (diabetes: 162 +/- 79 ng/mL, P < .001; IGT: 102 +/- 37 ng/mL, P < .001) compared with the NGT group (55 +/- 48 ng/mL). Soluble CD40L levels were also higher in those with diabetes and IGT (diabetes: 3.2 +/- 2.0 ng/mL, P < .001; IGT: 2.0 +/- 1.3 ng/mL, P < .001) compared with the NGT group (1.1 +/- 0.9 ng/mL). Subjects with MS had significantly higher levels of sP-selectin (with MS, 118 +/- 76 ng/mL; without MS, 95 +/- 66 ng/mL; P = .028) and sCD40L (with MS, 2.4 +/- 1.8 ng/mL; without MS, 1.9 +/- 1.5 ng/mL; P = .036) compared with subjects without MS. Among subjects with NGT and IGT, the mean levels of sP-selectin (tertile I, 65.0 ng/mL; tertile II, 80.0 ng/mL; tertile III, 91.0 ng/mL) and sCD40L levels (tertile I, 1.2 ng/mL; tertile II, 1.7 ng/mL; tertile III, 1.8 ng/mL) increased with increase in tertiles of homeostasis assessment model-insulin resistance, and the difference reached statistical significance in the last tertile compared with the first tertile (P < .05). This study demonstrates that increased levels of sP-selectin and sCD40L are seen in Asian Indian subjects with IGT, type 2 diabetes mellitus, MS, and insulin resistance.     

Nocturnal elevation of glucose levels during fasting in noninsulin-dependent diabetes

To define the spontaneous diurnal variations in glucose regulation during fasting in noninsulin-dependent diabetes (NIDDM), we measured circulating levels of glucose, insulin, C-peptide, GH, cortisol, and glucagon at 15-min intervals in 11 patients with untreated diabetes and 7 matched control subjects studied during a 24-h period. The rates of insulin secretion were derived from the concentrations of C-peptide by deconvolution using a two-compartment mathematical model for C-peptide distribution and metabolism. In both groups of subjects, despite continued fasting, glucose levels stopped declining in the evening and subsequently rose throughout the night to reach a morning maximum. Elevated levels persisted until noon. The morning glucose maximum corresponded to a relative increase of 23.8 +/- 5.5% above the evening nadir in NIDDM patients and 13.2 +/- 4.6% in nondiabetic subjects (P less than 0.05). In NIDDM patients, insulin levels and insulin secretion rates did not parallel the nocturnal glucose changes. In contrast, in control subjects, this nocturnal glucose rise coincided with a similar increase in insulin secretion rates. Cortisol concentrations in patients with NIDDM were higher than those in control subjects throughout the study period (P less than 0.001) and rose earlier in the evening than in control subjects, thus failing to demonstrate the normal nocturnal suppression. In both groups of subjects, the nighttime glucose elevation was temporally and quantitatively correlated with the circadian cortisol rise. GH secretion was increased in the evening and nighttime periods compared to the daytime values, and in NIDDM patients, but not in control subjects, the size of the morning glucose elevation was directly related to the magnitude of this increase in GH secretion (r = 0.88; P less than 0.01). Glucagon concentrations were similar in both groups of subjects and remained essentially constant throughout the study period. We hypothesize that the nocturnal glucose rise that occurs during fasting represents a normal diurnal variation in the set-point of glucose regulation amplified by counterregulatory mechanisms activated by the fasting condition.     

How insulin resistant are patients with noninsulin-dependent diabetes mellitus?

The study was carried out to quantify the ability of physiological increases in the plasma insulin concentration to stimulate glucose disposal above basal levels in 25 normal subjects and 25 patients with noninsulin-dependent diabetes mellitus (NIDDM). Patients were sex, age, and weight matched, and glucose disposal was determined under basal conditions (plasma insulin, approximately 10 microU/ml) and after plasma insulin levels had been increased to approximately 90 microU/ml. The mean (+/- SEM) glucose disposal rate was significantly greater (P less than 0.001) under basal conditions in patients with NIDDM (110 +/- 5 mg/m2 X min) than in individuals with normal glucose tolerance (77 +/- 4 mg/m2 X min). Glucose disposal rates increased in both normal subjects and NIDDM patients when plasma insulin concentrations were increased to about 90 microU/ml; however, the increment was much greater in normal subjects. Thus, glucose disposal only rose to a mean (+/- SEM) value of 145 +/- 7 mg/m2 X min in patients with NIDDM, representing an approximate 30% increase due to insulin. In contrast, a similar elevation of plasma insulin in normal subjects resulted in an increase in glucose disposal of approximately 300%, reaching a mean (+/- SEM) value of 310 +/- 24 mg/m2 X min. These results indicate that the defect in insulin-stimulated glucose uptake is significantly greater in patients with NIDDM than has previously been found.