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Query: UMLS:C0011854 (type 1 diabetes)
 20,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously demonstrated that hyperinsulinemia can amplify the counterregulatory response to hypoglycemia in normal subjects. The aim of the present study was to determine if differing concentrations of insulin can modify the counterregulatory response to equivalent fixed hypoglycemia in insulin-dependent-diabetic subjects (IDDM). Experiments were carried out in seven lean, overnight-fasted, moderately controlled (hemoglobin A1c, 10.9%; normal range, 5-9) IDDM subjects with a disease duration of 13 +/- 3 yr. All were maintained normoglycemic overnight so that basal plasma glucose (5.6 +/- 0.2 and 5.4 +/- 0.2 mmol/L) and insulinemia (63 +/- 18 and 48 +/- 10 pmol/L) were similar at the start of each study. Insulin was infused for 120 min in two separate randomized protocols, so that steady state levels (mean +/- SE) of 742 +/- 212 pmol/L (low) and 3360 +/- 710 pmol/L (high) were obtained. Glucose was infused during both protocols to ensure that the rate of fall of plasma glucose (0.09 mmol/L.min) and the hypoglycemic plateau (2.8 +/- 0.1 mmol/L) were similar. In response to hypoglycemia, plasma levels of epinephrine, norepinephrine, cortisol, GH, and pancreatic polypeptide increased similarly during both insulin infusions. During the final 30 min, despite similar levels of counterregulatory hormones, hepatic glucose production was significantly reduced in the presence of high compared to low insulin levels (1.7 +/- 2.8 vs. 8.3 +/- 1.7 mumol/kg.min; P < 0.05). Similarly, plasma nonesterified fatty acids (472 +/- 94 vs. 787 +/- 105 mumol/L) and blood 3-hydroxybutyrate levels (30 +/- 12 vs. 106 +/- 29 mumol/L) were significantly reduced (P < 0.05) during high compared to low dose infusions. Cardiovascular parameters (heart rate and systolic, diastolic, and mean arterial pressures) responded similarly during both infusions. We conclude that 1) insulin per se does not amplify the counterregulatory response to equivalent hypoglycemia in individuals with moderately controlled, long duration IDDM; and 2) there may be a relative autonomic adrenomedullary deficit in some IDDM subjects that prevents the amplified epinephrine response to hyperinsulinemia during hypoglycemia.
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PMID:The effects of insulin on the counterregulatory response to equivalent hypoglycemia in patients with insulin-dependent diabetes mellitus. 807 24

From the present review it appears that insulin-dependent diabetes is a common finding in chronic pancreatitis, and impaired secretion of insulin from beta-cells of the pancreatic islets is essential for the development of this form of secondary diabetes. Judged from a positive correlation between insulin secretory capacity and stimulated pancreatic enzyme output, beta-cell function may decrease in parallel with exocrine pancreatic function. However, in patients with insulin-dependent diabetes secondary to chronic pancreatitis beta-cell function was preserved to a greater extent and glucoregulation was better than in comparable Type 1 (insulin-dependent) diabetic patients. Immunological phenomena and associations with certain HLA-alleles characterizing Type 1 diabetes mellitus were not found in insulin-dependent diabetes secondary to chronic pancreatitis. This may contribute to the slower destruction of the beta-cells in chronic pancreatitis than encountered in Type 1 diabetes. The small number of chronic pancreatitis patients who developed totally absence of endogenous insulin production still have some alpha-cell function during i.v. arginine and meal stimulation. However, insulin-induced hypoglycemia and insulin withdrawal did not stimulate glucagon secretion in the secondary diabetic patients in contrast to comparable Type 1 diabetics. Nevertheless, blood glucose counterregulation is intact in the secondary diabetics due to preserved catecholamine secretion. Furthermore, ketonemia develops during dissipation of insulin, in spite of absence of increased glucagon secretion, emphasizing the role of insulin dissipation for the development of ketoacidosis in this form of diabetes. The suggested increased susceptibility to severe hypoglycemia and less tendency to development of ketonemia may further be influenced by altered insulin sensitivity, nutritional factors and concomitant hepatic failure in diabetes secondary to chronic pancreatitis. Pancreatic polypeptide secretion was absent in chronic pancreatitis without endogenous insulin production. Pancreatic polypeptide secreting cells thus seem to be at least as vulnerable as the beta-cells to the destructive processes characterizing chronic pancreatitis, whereas glucagon secreting alpha-cells preserve secretory capacity to a greater extent than PP-cells and beta-cells. No data, however, favour the view that absent pancreatic polypeptide secretion has any major effect on the glucoregulation in diabetes secondary to chronic pancreatitis. Increased plasma concentration of somatostatin was found in patients with insulin-dependent diabetes secondary to chronic pancreatitis. The source of somatostatin in the patients is unknown, but somatostatin may contribute to a reduction in overall blood glucose level in patients without endogenous insulin secretion due to inhibition of glucagon secretion.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Diabetes mellitus secondary to chronic pancreatitis. 849 94

The following studies show that insulin-induced hypoglycaemia increases the gastric emptying rate for both liquids and solid food in healthy volunteers and in patients with IDDM of short duration. This response to low blood glucose concentrations may help protect against sustained hypoglycaemia by increasing the uptake of ingested carbohydrates. The results suggest that gastric emptying in patients with diabetes should be examined under conditions that are standardized with respect to blood glucose concentration. The finding that cholinergic muscarinic blockade with atropine inhibited the hypoglycaemia-induced acceleration of gastric emptying indicates that vagal stimulation plays an important role in this mechanism. The fact that plasma pancreatic polypeptide concentrations were unchanged during hypoglycaemic episodes in the presence of atropine indicates that complete inhibition of the cholinergic transmission was achieved. It is not yet established whether hypoglycaemia directly stimulates vagal activity or whether this is achieved through the activation of hormones or other second messengers. It is likely, however, that vagal activity is an important determinant of the varying rate of gastric emptying at different glycaemic levels. The pancreatic polypeptide response in the atropine-treated subjects resembles that seen in diabetic patients with autonomic neuropathy when exposed to insulin-induced hypoglycaemia. Disturbances of vagal function are frequent in diabetic patients with autonomic neuropathy, and can lead to a reduction in the stimulated gastric output. A failure to increase gastric emptying in response to hypoglycaemia would be disadvantageous when ingestion of oral carbohydrates is used to restore normoglycaemia, and diabetic patients with autonomic neuropathy could therefore be at increased risk for severe hypoglycaemia. The influence of glycaemia on vagal activity and gastric emptying rate probably alters the optimal time interval between insulin injections and postprandial increases in the blood glucose concentration in patients treated with short-acting insulin administered at mealtimes. This may cause variations in blood glucose concentrations. Furthermore, it is possible that drugs that have anticholinergic effects (such as tricyclic antidepressants) may deleteriously decrease the gastric emptying rate during hypoglycaemia in diabetic patients.
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PMID:Hypoglycaemia and gastric emptying. 889 67

Vervet monkeys (Cercopithecus aethiops) used for pancreatic endocrine cell distribution studies were found to have been maintained on different diets. Although the effect of dietary changes on the exocrine pancreas has been described in several animals, little, apart from the effect of malnutrition, has been reported for the endocrine pancreas. Reported here are pancreatic endocrine cell distributions in monkeys on a standard diet (n = 3) compared with monkeys on an atherogenic diet (n = 3). Quantitation of immunolabelled pancreatic endocrine cell types revealed a significant 80% increase in A (glucagon) cell volume in monkeys on an atherogenic diet concomitant with a significant reduction in B (insulin) cell volume to approximately 60% of normal. This reflects a pattern of events that occurs in non-insulin dependent diabetes. An accompanying reduction in PP (pancreatic polypeptide) cell volumes supports our hypothesis that altering A and PP cell volumes could reflect differential gene expression in those cells in the adult in which glucagon and PP are co-localized.
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PMID:The effect of diet on the Vervet monkey endocrine pancreas. 943 24

We tested the hypothesis that as few as two weekly brief episodes of superimposed hypoglycemia (i.e., doubling the average frequency of symptomatic hypoglycemia) would reduce physiological and behavioral defenses against developing hypoglycemia and reduce detection of clinical hypoglycemia in patients with type 1 diabetes mellitus (T1DM). Compared with nondiabetic controls, six patients with well-controlled T1DM (HbA1c, 7.5 +/- 0.7% [mean +/- SD]) exhibited absent glucagon responses and reduced epinephrine (P = 0.0027), norepinephrine (P = 0.0007), pancreatic polypeptide (P = 0.0030), and neurogenic symptom (P = 0.0451) responses to hypoglycemia as expected. In these patients, 2 h of induced hypoglycemia (50 mg/dl, 2.8 mmol/l) twice weekly for 1 month, compared in a random-sequence crossover design with an otherwise identical 2 h of induced hyperglycemia (150 mg/dl, 8.3 mmol/l) twice weekly for 1 month, further reduced the epinephrine (P = 0.0001) and pancreatic polypeptide (P = 0.0030) responses, tended to further reduce the norepinephrine and neurogenic symptom responses to hypoglycemia, and reduced cognitive dysfunction during hypoglycemia (P = 0.0271), all assessed in the investigational setting. In the clinical setting, induced hypoglycemia did not alter overall glycemic control, but did reduce the total number of symptomatic hypoglycemic episodes detected by the patients from 49 to 30 per month and lowered the mean +/- SE self-monitored blood glucose level during symptomatic hypoglycemia from 51 +/- 2 mg/dl (2.8 +/- 0.1 mmol/l) to 46 +/- 3 mg/dl (2.6 +/- 0.2 mmol/l) (P < 0.01). It also reduced the proportion of low regularly scheduled self-monitored values that were symptomatic by approximately 33%. Thus as little as doubling the frequency of symptomatic hypoglycemia further reduced both the key epinephrine response and clinical awareness of developing hypoglycemia, changes reasonably expected to increase the risk of severe iatrogenic hypoglycemia in T1DM.
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PMID:Brief twice-weekly episodes of hypoglycemia reduce detection of clinical hypoglycemia in type 1 diabetes mellitus. 972 37

Duct cell adenocarcinomas may produce neuroendocrine markers such as pancreatic polypeptide, gastrin and gastrin releasing hormones. A 53 year old patient, with a history of insulin dependent diabetes, was found to have a pancreatic mass which was later pathologically demonstrated to be a duct cell adenocarcinoma. The tumor produced elevated circulating neuroendocrine markers specifically gastrin and pancreatic polypeptides. An 111In Octreotide imaging showed definite uptake of Octreotide by the tumor. The patient was subsequently treated with Somatostatin analog which resulted in the reduction of some of the circulating endocrine markers. The patient had essentially six months of asymptomatic clinical remission but then she relapsed. Octreotide scanning could be useful for selected patients with pathologic diagnosis of duct cell adenocarcinoma, because some tumors may have neuroendocrine features and can be imaged, and might even respond to Somatostatin analog therapy.
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PMID:Pancreatic duct cell carcinoma with positive 111In Octreotide uptake. 1096 25

Neuroendocrine responses (adrenaline, noradrenaline and pancreatic polypeptide (PP)) to hypoglycaemia are often diminished in long-term diabetic patients, but the role of autonomic nervous system changes in these reductions is not yet fully clarified. In order to establish whether such changes in neuroendocrine responses occur early in the course of diabetes, we investigated the responses to insulin-induced hxypoglycaemia during the first year of type 1 diabetes. Autonomic and somatic nerve function tests were performed concomitantly. Six type 1 diabetes patients were studied 3 and 12 months after diagnosis of diabetes. Hypoglycaemia was induced by i.v. insulin infusion after an overnight normalization of blood glucose. Autonomic nerve function was evaluated by cardiovascular tests, and somatic nerve function by nerve conduction velocities A 50% reduction was found in adrenaline (p < 0.025) and noradrenaline (p < 0.05) responses to hypoglycaemia; PP, too, was significantly diminished at 12 months compared with 3 months after diagnosis of type 1 diabetes. Rate of glucose recovery did not differ at month 12 compared with month 3. Cardiovascular autonomic nerve function tests did not change and remained within the normal range throughout the study. Altered neuroendocrine responses to hypoglycaemia may occur early in the course of type 1 diabetes. These are unlikely to be due to structural changes (i.e. autonomic neuropathy), but rather to changes in central nervous system activity patterns, i.e. a higher threshold (i.e. a lower blood glucose level) for hypothalamic activation of the sympathoadrenal system.
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PMID:Neuroendocrine responses to hypoglycaemia decrease within the first year after diagnosis of type 1 diabetes. 1176 11

Hypoglycemia-associated autonomic failure (HAAF)-reduced autonomic (including adrenomedullary epinephrine) and symptomatic responses to hypoglycemia caused by recent antecedent hypoglycemia-plays a key role in the pathogenesis of defective glucose counterregulation and hypoglycemia unawareness and thus iatrogenic hypoglycemia in type 1 diabetes. On the basis of the findings that cortisol infusion mimics and deficient or inhibited cortisol secretion minimizes this phenomenon, it has been suggested that the cortisol response to antecedent hypoglycemia mediates HAAF. We tested the hypothesis that any stimulus that releases cortisol, such as exercise, reduces autonomic and symptomatic responses to subsequent hypoglycemia. Thirteen healthy young adults (four women) were studied on three occasions in random sequence: 1) cycle exercise ( approximately 70% peak oxygen consumption) from 0830 to 0930 h and from 1200 to 1300 h on day 1 and hyperinsulinemic (2.0 mU x kg(-1) x min(-1)) stepped hypoglycemic (85, 75, 65, 55, and 45 mg/dl) clamps on day 2, 2) rest on day 1 and identical hypoglycemic clamps on day 2, and 3) hyperinsulinemic-euglycemic clamps. Exercise raised plasma cortisol concentrations to 16.9 +/- 1.9 (0930 h) and 16.6 +/- 1.6 microg/dl (1300 h) on day 1. Compared with rest on day 1, exercise on day 1 was associated with reduced epinephrine (P = 0.0113) responses-but not norepinephrine (P = 0.6270), neurogenic symptom (P = 0.6470), pancreatic polypeptide (P = 0.0629), or glucagon (P = 0.0436, but higher) responses-to hypoglycemia on day 2. However, the effect was small. (The final day 2 hypoglycemia epinephrine values were 765 +/- 106 pg/ml after rest on day 1 and 550 +/- 94 pg/ml after exercise on day 1 compared with 30 +/- 6 pg/ml during euglycemia.) These data are consistent with the hypothesis that the cortisol response to hypoglycemia mediates in part the reduced epinephrine response to subsequent hypoglycemia, one key component of HAAF in type 1 diabetes. However, the small effect suggests that an additional factor or factors may well be involved. These data do not support the hypothesis that the cortisol response to hypoglycemia mediates the reduced neurogenic symptom response to subsequent hypoglycemia, another key component of HAAF in type 1 diabetes.
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PMID:Limited impact of vigorous exercise on defenses against hypoglycemia: relevance to hypoglycemia-associated autonomic failure. 1197 46

A marked sexual dimorphism in neuroendocrine and metabolic responses to moderate, prolonged exercise occurs in healthy humans. It is unknown whether similar differences occur in type 1 diabetes mellitus (T1DM). Fifteen patients with T1DM (7 women and 8 men) were studied during 90 min of euglycemic exercise at 50% of the maximum rate of O(2) consumption. Men and women were matched for age, glycemic control, duration of diabetes, and exercise fitness, and had no history or evidence of autonomic neuropathy. Hypoglycemia was scrupulously avoided during the week preceding tests. Exercise was performed under constant infusion of regular insulin (1 U/h) and a variable 20% dextrose infusion, as needed to maintain euglycemia. At 15-min intervals, neuroendocrine, metabolic (glucose kinetics, intermediate metabolism, lipolysis), and cardiovascular responses were assessed. Indirect calorimetry was performed during the last 10 min of exercise. Plasma glucose and insulin did not differ between genders at baseline or during exercise. Key neuroendocrine responses were significantly reduced in women, compared with men, during exercise (epinephrine, 360 +/- 104 vs. 666 +/- 126 pM; norepinephrine, 2.3 +/- 0.8 vs. 4.1 +/- 1.0 nM; GH, 10 +/- 5 vs. 22 +/- 8 micro g/liter). Glucagon, cortisol, and pancreatic polypeptide responses were similar between genders. Despite reduced catecholamine responses in women, no gender differences were observed in endogenous glucose production (EGP) or exogenous glucose infusion rate during exercise. The lipolytic response to exercise (blood glycerol), on the other hand, was greater in women than in men. In conclusion, a marked sexual dimorphism exists in counterregulatory responses to exercise in T1DM, including key neuroendocrine (catecholamine, GH) and metabolic (lipolysis) responses. Other responses, including glucagon and EGP, were similar between genders, suggesting that the glucagon to insulin ratio may be the primary determinant of EGP during moderate intensity exercise in T1DM.
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PMID:Effect of gender on counterregulatory responses to euglycemic exercise in type 1 diabetes. 1241 85

BACKGROUND: Glucagon-like peptide-1 (GLP-1) and its agonists are under assessment in treatment of type 2 diabetes, by virtue of their antidiabetic actions, which include stimulation of insulin secretion, inhibition of glucagon release, and delay of gastric emptying. We examined the potential of GLP-1 to improve glycemic control in type 1 diabetes with no endogenous insulin secretion. METHODS: Dose-finding studies were carried out to establish mid range doses for delay of gastric emptying indicated by postponement of pancreatic polypeptide responses after meals. The selected dose of 0.63 micrograms/kg GLP-1 was administered before breakfast and lunch in 8-hour studies in hospital to establish the efficacy and safety of GLP-1. In outside-hospital studies, GLP-1 or vehicle was self-administered double-blind before meals with usual insulin for five consecutive days by five males and three females with well-controlled C-peptide-negative type 1 diabetes. Capillary blood glucose values were self-monitored before meals, at 30 and 60 min after breakfast and supper, and at bedtime. Breakfast tests with GLP-1 were conducted on the day before and on the day after 5-day studies. Paired t-tests and ANOVA were used for statistical analysis. RESULTS: In 8-hour studies time-averaged incremental (delta) areas under the curves(AUC) for plasma glucose through 8 hours were decreased by GLP-1 compared to vehicle (3.2 PlusMinus; 0.9, mean PlusMinus; se, vs 5.4 PlusMinus; 0.8 mmol/l, p <.05), and for pancreatic polypeptide, an indicator of gastric emptying, through 30 min after meals (4.0 PlusMinus; 3.1 vs 37 PlusMinus; 9.6 pmol/l, p <.05) with no adverse effects. Incremental glucagon levels through 60 min after meals were depressed by GLP-1 compared to vehicle (-3.7 PlusMinus; 2.5 vs 3.1 PlusMinus; 1.9 ng/l, p <.04). In 5-day studies, AUC for capillary blood glucose levels were lower with GLP-1 than with vehicle (-0.64 PlusMinus; 0.33 vs 0.34 PlusMinus; 0.26 mmol/l, p <.05). No assisted episode of hypoglycaemia or change in insulin dosage occurred. Breakfast tests on the days immediately before and after 5-day trials showed no change in the effects of GLP-1. CONCLUSION: We have demonstrated that subcutaneous GLP-1 can improve glucose control in type 1 diabetes without adverse effects when self-administered before meals with usual insulin during established intensive insulin treatment programs.
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PMID:Glucagon-like peptide 1 improved glycemic control in type 1 diabetes. 1269 69


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