Insulin and glucagon secretion in diabetic and non-diabetic patients with circulating islet cell antibodies

Summary Thirty-nine patients (14 non-diabetics, 8 chemical diabetics, and 17 overt diabetics) with circulating islet cell antibodies (ICA) were studied. Insulin and glucagon secretion after oral (100 g) and intravenous glucose loading (200 mg/kg bolus injection followed by an infusion of 20 mg/min over 60 min) and arginine infusion (25 g over 30 minutes) were evaluated in these patients and in non diabetic and diabetic ICA-negative controls. In the non-diabetic groups with or without ICA, insulin and glucagon responses to glucose were similar. Moreover, in ICA positive patients the response of these hormones to arginine infusion was reduced. Similar alterations in insulin and glucagon secretion were observed in the ICA positive and negative patients with chemical or overt diabetes. In particular, fasting hyperglucagonaemia and glucagon hyperresponse to arginine are associated with a lack of insulin secretion in the patients with overt diabetes. Hormonal differences between diabetics with and without ICA could not be detected.This work was previously presented at the 12th Meeting of the European Association for the Study of Diabetes, Helsinki, September 1976 and published in abstract form in Diabetologia12, 422 (1976)     

Lack of influence of arginine preloading on the insulin response to I.V. glucagon in children and adolescents

Summary Nine normal children (6 males and 3 females) aged from 7 1/2 to 14 1/2 years underwent a 30-min arginine infusion (0.5 g/kg) followed at 90 min by one bolus i.v. glucagon injection (0.03 mg/kg). On a separate occasion the same children underwent an i.v. glucagononly test. No significant difference was found when the glucose and insulin responses in the two glucagon tests were compared, in contrast to previous findings that preloading with glucose resulted in a significantly increased response of insulin to glucagon. Established Investigator of the Chief Scientist’s Bureau Ministry of Health.     

Abnormal glucagon response to arginine and its normalization in obese hyperinsulinaemic patients with glucose intolerance: importance of insulin action on pancreatic Alpha cells

Summary An excessive glucagon secretion to intravenous arginine infusion was found in obese hyperinsulinaemic patients with glucose intolerance. This study was designed to determine whether the glucagon hyperresponsiveness to arginine in these patients would improve by insulin infused at a high enough dose to overcome insulin resistance. By infusing high dose insulin during arginine infusion, the previously exaggerated glucagon response to arginine could be normalized. To normalize the abnormal glucagon response, insulin doses of 4.2±0.7 and 3.8±0.5 IU were required during arginine infusion in obese hyperinsulinaemic patients with impaired glucose tolerance and Type 2 (non-insulin-dependent) diabetes mellitus, respectively. This achieved plasma peak insulin levels 3 to 4 times higher than those observed in non-obese healthy subjects. Furthermore, we clarified whether or not the effect of normalizing insulin action and/or glycaemic excursions contributed to normalizing the exaggerated glucagon response to arginine in these patients. Blood glucose was clamped while high dose insulin was infused at the same levels as observed during the arginine infusion test with no insulin infusion. As a result, normalization of the exaggerated plasma glucagon response was achieved, whether hyperglycaemia existed or not. These results clearly demonstrate that, similar to non-obese hypoinsulinaemic Type 1 (insulin-dependent) and Type 2 (non-insulin-dependent) diabetic patients, the exaggerated Alpha-cell response to arginine infusion in obese hyperinsulinaemic patients with glucose intolerance is secondary to the reduction of insulin action on the pancreatic Alpha cell, and that the expression of insulin action plays an important part in normalizing these abnormalities.     

Comparative insulinogenic effects of glucose,arginine and glucagon in patients with diabetes mellitus,endocrine disorders and liver disease

Summary In order to compare the insulinogenic effects of glucose, arginine and glucagon, plasma immunoreactive insulin levels following oral glucose loading (50 g), intravenous arginine infusion (30 g for 45 min) and intravenous glucagon injection (1 mg) were determined in patients with diabetes mellitus, various endocrine diseases and chronic hepatitis. In patients with Cushing’s syndrome, plasma insulin responses to all three stimuli were exaggerated, whereas they were low in patients with pheochromocytoma. In other diseases, certain disparities were observed in plasma insulin responses. In patients with mild diabetes mellitus, insulin secretion elicited by glucose seems to be selectively impaired, because arginine and glucagon caused a rise in plasma insulin not significantly different from that in normal subjects. In patients with hyperthyroidism, plasma insulin responses to arginine and glucagon were either absent or limited, although rather a exaggerated response was noted following oral glucose loading. On the contrary, exaggerated responses to arginine and glucagon, and limited response to glucose were observed in hypothyroidism. In patients with chronic hepatitis, the responses of plasma insulin to glucose and arginine were both exaggerated, whereas the response to glucagon was comparable to that in normal subjects. These disparate responses suggest that glucose, arginine and glucagon act on the B-cell via different mechanisms.     

Effect of free fatty acids and amino acids on glucagon and insulin secretions in normal and diabetic ducks

Summary The relationship between two metabolites, free fatty acids (FFA) and amino acids (AA), and the two main pancreatic hormones, insulin and glucagon, was studied by infusing small amounts of these metabolites into normal and diabetic Peking ducks, i. e. two days after subtotal pancreatectomy. Infusion of oleic acid (0.365 g/kg/30 min as an emulsion in plasma) indicated a suppressive effect of free fatty acids on glucagon secretion, but was without effect on insulin secretion, in normal as well as in diabetic ducks, indicating that insulin might not be directly involved in the FFA-glucagon feedback in the duck. Infusions of arginine for one hour (1 g/kg/h) into normal ducks, hyperglycaemic normal birds (as a result of glucose infusion: 1 g/kg/h) and diabetic ducks, suggested the persistence of an amino acid effect on glucagon secretion, and a slight reduction of the effect on insulin secretion in diabetes. This suggests that insulin may not be involved in amino acidinduced glucagon secretion in the duck.     

On the pathogenesis of maturity-onset diabetes mellitus

Conclusions At the 6th IDF Congress in Stockholm in 1967, a hypothesis for the pathogenesis of maturity-onset diabetes under the title ‘What is inherited — what is added?’ was put forward. Investigations over the past 10 years, on the whole, tend to confirm our concept that the capacity of the pancreatic beta-cell to respond to a standardized glucose infusion with insulin production, to a major degree, is genetically controlled. Therefore, our original idea that impaired insulin response to glucose is a marker of genetic diabetes in all its stages (prediabetes, chemical diabetes, manifest diabetes) seems plausible. Accordingly, a malfunction in the transmission of information about the blood glucose level in the extracellular fluid to those sites in the cells which regulate insulin release, would be the primary defect in genetic diabetes. Our studies suggest that, due to increased sensitivity of the liver to insulin in the portal vein, most prediabetics retain a relatively normal — although somewhat low — glucose tolerance. This compensatory mechanism becomes insufficient and glucose intolerance is precipitated, e.g., when the demand for insulin release is increased. This occurs when the sensitivity of the body for insulin diminishes as in the case of obesity, acromegaly and pregnancy and, maybe, also during the process of aging.     

Insulin and glucagon release in the diabetic Chinese hamster: Differences among inbred sublines

Summary Release of insulin and glucagon from perfused pancreases in vitro of 40 normal male and female Chinese hamsters (from one inbred subline) and 110 male and female diabetic hamsters (from three inbred sublines) was measured in response to glucose plus arginine, theophylline alone, or potassium alone, in order to determine if differences in hormone secretion exist among different diabetic sublines. Glucose plus arginine and potassium produced subnormal insulin responses in all three diabetic sublines, whereas theophylline induced normal or above normal insulin responses. Excessive glucagon release was consistently seen in only one diabetic subline. The female normal animals showed greater insulin release than the male normal hamsters in response to glucose plus arginine. This sex difference was not seen in the diabetic animals.     

Evaluation of insulin resistance during inhibition of endogenous insulin and glucagon secretion by somatostatin in non-obese subjects with impaired glucose tolerance

Summary Insulin resistance was studied in seven non-obese male subjects with impaired glucose tolerance and four healthy, age and body-weight matched male control subjects by means of a continuous intravenous infusion of somatostatin, glucose and insulin over 150 min. Glucose tolerance was evaluated by means of a 2-h glucose infusion test. Endogenous insulin (C-peptide), growth hormone, and glucagon secretion were suppressed by somatostatin in both groups. Steady-state plasma insulin and glucose levels were achieved between 90–135 min. Since similar steady-state levels of exogenous insulin were achieved, the resulting steady-state plasma glucose level provided a direct estimate of the ability of insulin to dispose of the infused glucose. The glucose levels were higher in subjects with impaired glucose tolerance with values of 14.6 ± 1.8 mmol/1 compared with 5.1 ± 1.2 mmol/1 in control subjects (p < 0.01), thus indicating insulin resistance. There was a direct correlation between the steady-state plasma glucose level and glucose tolerance suggesting that the degree of glucose intolerance is proportional to the degree of insulin resistance. These results revealed that decreased insulin sensitivity is found in non-obese subjects with impaired glucose tolerance.     

Does glucagon play a role in the insulin resistance of patients with adult non-ketotic diabetes?

Summary Using a constant intravenous infusion technique we have measured in vivo insulin resistance in 17 normal subjects, five patients with chemical diabetes, and 13 non-ketotic diabetic patients with fasting hyperglycaemia (FBS>120 mg/ 100 ml). All of the diabetic patients were non-obese. The results demonstrated that the diabetic patients were insulin resistant compared to normals and that the degree of insulin resistance was greater the more severe the diabetes. No differences in plasma glucagon levels were found among the different groups during the infusion studies. These results demonstrate that non-obese, non-ketotic diabetic patients are insulin resistant and that abnormalities in plasma glucagon concentrations do not account for this insulin resistance.Dr. Olefsky is a Clinical Investigator with the Veterans AdministrationDr. Sperling is a recipient of a Research Career Development Award from the U. S. P. H. S., 1K04-HD 00029Dr. Reaven is a Medical Investigator with the Veterans Administration     

The mechanism of exaggerated glucagon response to arginine in diabetes mellitus

As far as exaggerated arginine-induced glucagon secretion in diabetics is concerned, the authors have shown that both the restoration of blood glucose excursions and physiological insulinemia in response to arginine, obtained from an artificial endocrine pancreas (AEP) could normalize the glucagon secretory responses in diabetes mellitus. To clarify whether or not physiological glycemic excursions and/or plasma insulin profiles contribute to the normalization of the exaggerated glucagon response in diabetes mellitus, the following 4 investigations were conducted on each of 7 non-obese, non-insulin-dependent diabetic (NIDDM), and 8 insulin-dependent diabetic (IDDM) subjects, with the aid of AEP. Arginine was i.v. infused into both diabetic groups (1) in a hyperglycemic state without insulin infusion, (2) in perfect glycemic control with insulin infusion by AEP, (3) in glycemic control with AEP, but with lower plasma insulin profiles (parameters of the insulin infusion algorithm were made smaller than those of (2], (4) in a state where blood glucose levels were clamped at the same levels as obtained in (1) with the aid of glucose infusion controlled by AEP, and where physiological plasma insulin profiles were mimicked by infusing insulin at the same rates used in (2) with a pre-programmable insulin infusion system. The changes in the plasma glucagon (IRG) response in each experiment were compared with those seen in healthy subjects. For both diabetic groups it was found that: in (2) perfect normalization of glucagon response was achieved.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reactive hypoglycaemia following GLP‐1 infusion in pancreas transplant recipients

The aim of the study was to determine whether reactive hypoglycaemia in pancreas transplant recipients that followed administration of glucagon‐like peptide‐1 (GLP‐1) was associated with excessive insulin, insufficient glucagon, or both. Methodology involved six portally drained pancreas recipients who received GLP‐1 (1.5 pmol/kg/min) or placebo infusion on randomized occasions during glucose‐potentiated arginine testing. The second subject developed symptomatic hypoglycaemia [plasma glucose (PG) 42 mg/dl] 1 h after GLP‐1 administration; subsequent subjects received intravenous glucose following GLP‐1, but not placebo, infusion for PG levels <65 mg/dl. Following GLP‐1 vs. placebo infusion, PG was lower (58 ± 4 vs. 76 ± 5 mg/dl; p < 0.05) despite administration of intravenous glucose. During hypoglycaemia, insulin levels and the insulin‐to‐glucagon ratio were greater after GLP‐1 vs. placebo infusion (p < 0.05), while glucagon did not vary. It can be concluded from the study that GLP‐1 can induce reactive hypoglycaemia in pancreas transplant recipients through excessive insulin secretion associated with an increased insulin‐to‐glucagon ratio.     

The metabolic response to norepinephrine in normal versus diabetic man

Summary Norepinephrine was infused for 60 minutes in high physiological concentration (0.08 μg/ kg/min) into seven insulin dependent diabetic subjects with no demonstrable endogenous insulin secretion and into seven normal subjects. Insulin dependent diabetic subjects had a stable, free insulin concentration of 23±5 μU/ml which was unaffected by norepinephrine infusion. In the normal subjects, norepinephrine induced an initial inhibition of insulin secretion which lasted for approximately 20 minutes. Norepinephrine infusion caused a rapid increase in both ketone body and glucose concentrations but this response did not differ between the two groups. In contrast, plasma nonesterified fatty acid and triglyceride concentrations were increased significantly more in the normal than in the diabetic subjects. The increase in plasma glucagon concentrations was similar in the two groups of subjects. The cause of the differential metabolic response to norepinephrine between the normal and diabetic groups was not resolved, but may be related, at least in part, to suppression of endogenous insulin secretion in the normal subjects.     

Metasomatotrophic diabetes and its induction: Basal insulin secretion and insulin release responses to glucose,glucagon, arginine and meals

Summary Growth hormone treatment produced somatotrophic diabetes, with hyperglycaemia, polyuria, glycosuria and elevation in serum non-esterified fatty acids (NEFA) in dogs. Early in this diabetes, fasting serum immunoreactive insulin (IRI) rose 20-fold, the insulin/glucose (I/G) ratio rose 10-fold and in response to glucose infusion, the rise in IRI was twice the normal. In the latter half of the continued growth hormone treatment, the intensity of the diabetes increased, serum IRI declined to the normal level and the I/G ratio became subnormal. Late in the treatment, following glucose infusion, there was no change in serum IRI, no fall in NEFA and further depression of glucose tolerance. In metasomatotrophic diabetes, in which hyperglycaemia, glycosuria and high NEFA level persisted, fasting serum IRI was normal during several months, then became subnormal and the I/G ratio was diminished further. Following glucose IV there was no change in serum IRI, no fall in NEFA and low glucose tolerance. The normally-occurring rises in serum IRI following arginine and glucagon IV and after the ingestion of a meal were absent. These permanently diabetic dogs were responsive to insulin IV. The insulin content of the pancreas was reduced to about 1.2% of the normal after 14 months of this diabetes. From the sequence of change it is concluded that growth hormone induced metasomatotrophic diabetes by causing excessive secretion of insulin under basal and stimulative conditions, leading to permanent loss of function of the beta cells of the pancreatic islets, to such an extent that basal insulin secretion was low and the ability to secrete extra insulin in response to stimuli was lost.     

Glucagon receptor antagonism improves islet function in mice with insulin resistance induced by a high-fat diet

Aims/hypothesis Increased glucagon secretion predicts deterioration of glucose tolerance, and high glucagon levels contribute to hyperglycaemia in type 2 diabetes. Inhibition of glucagon action may therefore be a potential novel target to reduce hyperglycaemia. Here, we investigated whether chronic treatment with a glucagon receptor antagonist (GRA) improves islet dysfunction in female mice on a high-fat diet (HFD). Materials and methods After 8 weeks of HFD, mice were treated with a small molecule GRA (300 mg/kg, gavage once daily) for up to 30 days. Insulin secretion was studied after oral and intravenous administration of glucose and glucagon secretion after intravenous arginine. Islet morphology was examined and insulin secretion and glucose oxidation were measured in isolated islets. Results Fasting plasma glucose levels were reduced by GRA (6.0 ± 0.2 vs 7.4 ± 0.5 mmol/l; p = 0.017). The acute insulin response to intravenous glucose was augmented (1,300 ± 110 vs 790 ± 64 pmol/l; p < 0.001). The early insulin response to oral glucose was reduced in mice on HFD + GRA (1,890 ± 160 vs 3,040 ± 420 pmol/l; p = 0.012), but glucose excursions were improved. Intravenous arginine significantly increased the acute glucagon response (129 ± 12 vs 36 ± 6 ng/l in controls; p < 0.01), notably without affecting plasma glucose. GRA caused a modest increase in alpha cell mass, while beta cell mass was similar to that in mice on HFD + vehicle. Isolated islets displayed improved glucose-stimulated insulin secretion after GRA treatment (0.061 ± 0.007 vs 0.030 ± 0.004 pmol islet⁻¹ h⁻¹ at 16.7 mmol/l glucose; p < 0.001), without affecting islet glucose oxidation. Conclusions/interpretation Chronic glucagon receptor antagonism in HFD-fed mice improves islet sensitivity to glucose and increases insulin secretion, suggesting improvement of key defects underlying impaired glucose tolerance and type 2 diabetes.     

Effect of a long acting glucagon selective somatostatin analogue on plasma glucose,insulin and glucagon levels in the anaesthetized rat during arginine infusion

Summary The effects of somatostatin and a long acting, glucagon selective somatostatin analog (des-Ala¹Gly²[His^4,5-D-Trp⁸]-somatostatin), were studied during arginine tolerance tests in normal anaesthetized rats. Arginine infusion in control animals resulted in a rapid increase in plasma insulin and glucagon, and an increase of 15±5 mg/dl in plasma glucose. Somatostatin infusion (1 mg/kg/h) resulted in suppression of basal insulin secretion and a decrease in arginine-induced insulin and glucagon release. Glucose levels increased rapidly during the combined arginine-somatostatin infusion reaching a peak of 72±10 mg/dl above basal levels. Similar results were obtained when somatostatin was injected SC (1 mg/kg) at times 0, 15, 30, and 45 minutes (arginine infused from 30–60 minutes). A single injection (1 mg/kg) of the long-acting somatostatin analogue resulted in significant inhibition of basal insulin and glucagon release; during arginine infusion glucagon levels rose only slightly, the insulin response was, however, nearly normal, and only a small arginine-induced increase in glucose levels was observed. Carbohydrate absorption was not influenced by either somatostatin or the analogue.     

Previous exposure to glucose enhances insulin and suppresses glucagon responses to argentine in man

Summary The effects of previous exposure to glucose on the insulin, glucagon, growth hormone and blood glucose responses to subsequent stimulation with L-arginine were investigated in normal man. During control conditions (i.e., after 120 min of saline infusion), the i.v. administration of arginine enhanced the release of all three hormones and caused a small and transient rise in blood glucose. When arginine was preceded by i.v. glucose during 0–60 min, followed by a rest period of 60–120 min, the insulin release induced by the amino acid was further enhanced, glucagon and GH release were unaffected and blood glucose depressed below control levels. When arginine was preceded by a small oral glucose load (0.5 g/kg) the initial insulin response to arginine was augmented, the initial glucagon response was slightly but significantly depressed and blood glucose lowered while the growth hormone response was unaffected. Conclusions: (1) a near-physiological intake of glucose increases insulin and depresses glucagon secretion evoked by amino acids resulting in increased glucose disposal; (2) the modifications of the insulin and glucagon responses constitute separate components in the feed-back regulation of glucose homeostasis.     

Diurnal variations in insulin secretion and insulin sensitivity in aged subjects

Summary Glucose tolerance tends to decrease in healthy aged subjects without family history of diabetes. Either reduced insulin secretion or insulin resistance may be responsible. Insulin secretion and insulin sensitivity were studied in 7 aged subjects (68–75 years) and 8 young controls (21–27 years). A 1-mg i.v. glucagon and a 5-U/m² body area i.v. insulin test were run in each subject at 07⁰⁰ and at 19⁰⁰ on two different days to detect diurnal variations. An arginine test was also performed to evaluate pancreatic glucagon behavior. In the evening, young subjects presented a glucose tolerance impairment with significantly decreased plasma insulin levels, and a reduced hypoglycemic effect of exogenous insulin. Resistance to both endogenous and exogenous insulin in the aged was observed in the morning without significant morning/evening variations. Since the response to contra-insular hormones (GH in the insulin test, glucagon in the arginine test) was the same in both age groups, their role in the phenomenon could be ruled out. It is suggested that in the aged a stable reduction in number and/or a change in affinity of insulin receptors may occur. In addition, since again is seen to be associated with the disappearance of diurnal variations in glucose tolerance and insulin secretion and sensitivity, and since a reduction in the receptor level of young healthy subjects in the evening has been reported by some authors, it is suggested that aged subjects may be less able to modulate the binding of insulin to its peripheral receptors in the course of the day.     

Relationship between body fat mass,carbohydrate tolerance and iri response during glucose infusion in subjects with early diabetes

Summary We have studied the interrelationship of total body fat mass, carbohydrate tolerance and IRI response in 17 non-obese and obese subjects, who were suspected of having early diabetes. We carried out an i.v. glucose infusion test consisting of a priming injection of 0.33 g/kg followed by constant glucose infusion of 12 mg/kg/min in all persons. Total body fat mass was estimated by the tritium dilution method. There was a positive correlation of body fat mass, fasting glucose concentration and blood glucose concentration at 150 min as well as a strong correlation between body fat mass and BG area 60–120 min as parameters of carbohydrate tolerance in all subjects, i.e. the degree of carbohydrate intolerance was directly related to the quantity of total body fat mass. A similar correlation was found when the non-obese and obese groups were analyzed separately. In neither group did total body fat mass correlate with parameters of IRI response. In obese subjects with pathological carbohydrate tolerance, however, a positive correlation of basal IRI concentration and total body fat mass was found. Furthermore, a close relation between basal IRI level and parameters of carbohydrate tolerance could be demonstrated in obese subjects. The present study failed to demonstrate any correlation of parameters of carbohydrate tolerance and glucose-induced IRI response in either group. Thus, the significant relationship between body fat mass and degree of carbohydrate intolerance indicates that total body fat mass plays an important role in the disturbance of blood glucose homeostasis in early diabetes with and without obesity. Investigation performed within the medical research project ‘Diabetes mellitus and disturbances of lipid metabolism’, Ministry of Health, GDR.     

Impaired incretin secretion and pancreatic dysfunction with older age and diabetes

Objective

To estimate the impact of aging and diabetes on insulin sensitivity, beta-cell function, adipocytokines, and incretin production.

Methods

Hyperglycemic clamps, arginine tests and meal tolerance tests were performed in 50 non-obese subjects to measure insulin sensitivity (IS) and insulin secretion as well as plasma levels of glucagon, GLP-1 and GIP. Patients with diabetes and healthy control subjects were divided into the following groups: middle-aged type 2 diabetes (MA-DM), aged Type 2 diabetes (A-DM) and middle-aged or aged subjects with normal glucose tolerance (MA-NGT or A-NGT).

Results

IS, as determined by the homeostasis model assessment, glucose infusion rate, and oral glucose insulin sensitivity, was reduced in the aged and DM groups compared with MA-NGT, but it was similar in the MA-DM and A-DM groups. Insulinogenic index, first and second phase insulin secretion and the disposition indices, but not insulin response to arginine, were reduced in the aged and DM groups. Postprandial glucagon production was higher in MA-DM compared to MA-NGT. Whereas the GLP-1 production was reduced in A-DM, no differences between groups were observed in GIP production.

Conclusions

In non-obese subjects, diabetes and aging impair insulin sensitivity. Insulin production is reduced by aging, and diabetes exacerbates this condition. Aging associated defects superimposed diabetic physiopathology, particularly regarding GLP-1 production. On the other hand, the glucose-independent secretion of insulin was preserved. Knowledge of the complex relationship between aging and diabetes could support the development of physiopathological and pharmacological based therapies.     

Failure to adequately adapt reduced insulin sensitivity with increased insulin secretion in women with impaired glucose tolerance

Summary To study the islet adaptation to reduced insulin sensitivity in normal and glucose intolerant post-menopausal women, we performed a euglycaemic, hyperinsulinaemic clamp in 108 randomly selected women, aged 58–59 years. Of the 20 women with the lowest insulin sensitivity, 11 had impaired glucose tolerance (IGT) whereas 9 had normal glucose tolerance (NGT). These women together with 15 women with medium insulin sensitivity and 16 women with high insulin sensitivity and NGT were further examined with arginine stimulation at three glucose levels (fasting, 14 and >25 mmol/l). In NGT, the acute insulin response (AIR) to 5 g i. v. arginine at all three glucose levels and the slope_AIR, i. e. the glucose potentiation of insulin secretion, were markedly increased in the women with the lowest insulin sensitivity and NGT compared to those with medium or high insulin sensitivity. In contrast, in low insulin sensitivity, AIR was significantly lower in IGT than in NGT (at glucose 14 mmol/l p=0.015, and at >25 mmol/l p=0.048). The potentiation of AIR induced by low insulin sensitivity in women with NGT was reduced by 74% (AIR at 14 mmol/l glucose) and 57% (AIR at >25 mmol/l glucose), respectively, in women with IGT. Also the slope_AIR was lower in IGT than in NGT (p=0.025); the increase in slope_AIR due to low insulin sensitivity was abolished in IGT. In contrast, glucagon secretion was not different between women with IGT as opposed to NGT. We conclude that as long as there is an adequate beta-cell adaptation to low insulin sensitivity with increased insulin secretory capacity and glucose potentiation of insulin secretion, NGT persists.Abbreviations NIDDM Non-insulin-dependent diabetes mellitus - AIR acute insulin response - AGR acute glucagon response