Pulsatile insulin delivery is more efficient than continuous infusion in modulating islet cell function in normal subjects and patients with type 1 diabetes.

The respective modulating effects of continuous and intermittent insulin delivery on pancreatic islet cell function were studied in seven normal men and nine insulin-dependent (type 1) diabetic patients. In the normal men, saline or continuous (0.8 mU kg-1 min-1) or pulsatile (5.

Oxytocin increases arginine-induced A and B cell secretion in normal man and in diabetic subjects.

In previous in Vitro and in Vivo studies oxytocin was shown to stimulate A and B cell secretion. In the present study we show that oxytocin is also able to increase arginine-induced glucagon and insulin secretion in healthy human beings. Similar results were obtained in both insulin-dependent (type-1) and non-insulin dependent (type-2) diabetic subjects.

Plasma glucose lowering effect of sparteine sulphate infusion in non-insulin dependent (type 2) diabetic subjects.

Sparteine sulphate, given i.v. as a bolus of 15 mg/ml plus 90 mg in 0.

Pharmacological doses of oxytocin affect plasma hormone levels modulating glucose homeostasis in normal man.

Pharmacological doses of oxytocin administered in basal conditions evoked a rapid surge in plasma glucose and glucagon levels followed by a later increase in plasma insulin and adrenaline levels. The effects of oxytocin on plasma glucagon and adrenaline levels were potentiated by hypoglycemia. When the endogenous pancreas secretion was suppressed by cyclic somatostatin (150 micrograms/h) and exogenous glucagon (3.

The addition of glipizide to insulin therapy in type-II diabetic patients with secondary failure to sulfonylureas is useful only in the presence of a significant residual insulin secretion.

The present study aimed at 1) investigating the effect of a combined insulin + glipizide treatment on the metabolic control (HbA1c levels) and insulin requirements (Biostator assessment) in ten non-obese Type-II diabetic patients with recent secondary failure to sulfonylureas; and 2) characterizing the relative contributions of changes in endogenous insulin secretion (C-peptide response) and insulin sensitivity (insulin-induced glucose disposal in clamped conditions) to this effect. The patients were treated in a randomized cross-over order with either insulin alone or insulin + glipizide (3 X 10 mg/day) during two periods averaging 6 weeks each. Mean HbA1c levels were similar in both experimental conditions (8.

Impaired insulin-mediated erythrocyte magnesium accumulation in essential hypertension.

1. This study was designed to investigate variations in erythrocyte magnesium in the presence of insulin (0.1 unit/l) in hypertensive subjects.

Prevention of metabolic alterations by insulin supplements administered either before or after 2-h nocturnal interruption of CSII.

To evaluate the efficacy of a bolus insulin injection to prevent the metabolic alterations induced by a 2-h nocturnal interruption of a continuous subcutaneous insulin infusion (CSII), nine type I (insulin-dependent) C-peptide-negative diabetic patients were studied from 2200 to 0800 h during two randomized tests. An insulin bolus (2.1 +/- 0.

Sodium salicylate restores the impaired insulin response to glucose and improves glucose tolerance in heroin addicts.

Plasma glucose, insulin, C-peptide, glucagon and growth hormone responses to intravenous glucose were evaluated in 10 heroin addicts in the basal state and during an infusion of sodium salicylate, an inhibitor of endogenous prostaglandin synthesis. Ten normal subjects, matched for age, sex and weight served as controls. In the basal state, the heroin addicts had markedly reduced insulin responses to intravenous glucose and low glucose disappearance rates (p less than 0.

Role of alpha and beta cells in the impaired glucose tolerance of thalassaemic subjects.

Fifty healthy and 12 thalassaemic subjects underwent both an oral glucose tolerance test (OGTT) and arginine test in order to investigate their alpha and beta cell activity. While basal plasma levels were similar in both group of subjects (82 +/- 4 vs 74 +/- 4 mg/dl, p = NS), following glucose intake impaired glucose tolerance was observed in thalassaemic subjects. These subjects showed impaired insulin secretion either in steady-state conditions or after glucose intake.

Primary role of glucagon release in the effect of beta-endorphin on glucose homeostasis in normal man.

The present study aimed at evaluating the effect of human beta-endorphin on pancreatic hormone levels and on glucose metabolism in normal subjects. Infusion of 143 nmol/h beta-endorphin in 7 subjects caused a significant rise in plasma glucose concentrations (+ 1.7 +/- 0.

Beta-endorphin infusion restores acute insulin responses to glucose in type-2 diabetes mellitus.

To address the possibility that an abnormality in pancreatic beta-endorphin activity might contribute to abnormal insulin secretion in diabetes mellitus, we studied the effects of beta-endorphin infusion on islet function in diabetic patients. The iv infusion of human beta-endorphin at a dose of 0.5 mg/h for 2 h in type-2 non-insulin-dependent diabetic patients (n = 12) raised plasma insulin and glucagon levels and slightly but significantly lowered plasma glucose concentrations.

Greater efficacy of pulsatile insulin in type I diabetics critically depends on plasma glucagon levels.

The aim of this study was to investigate the role of plasma glucagon levels on the blood glucose response to intravenous insulin administered continuously or in a pulsatile manner. Six type I diabetic patients proven to have no residual insulin secretion were investigated. Endogenous glucagon secretion was inhibited by a continuous intravenous infusion of somatostatin (100 micrograms/h) and replaced by exogenous infusions of the hormone at three different rates (7.

Pulsatile hyperglucagonemia fails to increase hepatic glucose production in normal man.

To study the metabolic effects of pulsatile glucagon administration, six male volunteers were submitted to a 260-min glucose-controlled glucose intravenous infusion using the Biostator. The endogenous secretion of the pancreatic hormones was inhibited by somatostatin (100 micrograms X h-1), basal insulin secretion was replaced by a continuous insulin infusion (0.2 mU X kg-1 X min-1), and glucagon was infused intravenously in two conditions at random: either continuously (125 ng X min-1) or intermittently (812.

Effect of sparteine sulphate upon basal and nutrient-induced insulin and glucagon secretion in normal man.

Infusion of a therapeutic dose of sparteine sulphate, increased the basal plasma insulin level and lowered plasma glucose. When an intravenous glucose tolerance test was performed with the infusion, the total insulin AUC was significantly larger than in absence of sparteine (2025 vs 1464 microU/ml X min), plasma glucose levels were lower and improved glucose utilization was observed (kg:1.55 vs 1.

Plasma calcitonin variations in normal women and in women with family history of diabetes during pregnancy.

In eight normal pregnant women and in eighteen women with a family history of diabetes, plasma calcitonin (CT), parathyroid hormone (PTH), insulin and glucagon variations and total plasma calcium levels were investigated. Calcitonin, parathyroid hormone and glucagon were all increased during the 2nd and 3rd trimester of pregnancy in normal women (N.W.

Effect of sparteine sulfate on insulin secretion in normal men.

This study aimed at evaluating the influence of sparteine sulfate either upon basal plasma glucose and insulin or glucose-induced insulin secretion in normal man. Thirteen overnight fasted volunteers took part in this study; five of them were submitted to sparteine sulfate bolus (15 mg in 10 ml of saline solution) followed by a slow infusion (90 mg/100 ml X 60 min) and eight subjects underwent two different glucose pulses (20 gr. i.

Insulin induces opposite changes in plasma and erythrocyte magnesium concentrations in normal man.

Plasma and erythrocyte magnesium levels were measured by atomic absorption spectrophotometry in 10 healthy volunteers during an oral glucose tolerance test and during an euglycaemic hyperinsulinaemic glucose clamp. At min 180 and 210 of the oral glucose tolerance test, a significant decline in plasma magnesium levels (p less than 0.01 and p less than 0.