Effect of indomethacin on the metabolic and hormonal response to a standardized breakfast in normal subjects

We have investigated the influence of a single oral administration of indomethacin on blood glucose, plasma free fatty acids (FFA), alpha-amino-nitrogen, insulin and glucagon concentrations in young healthy subjects. Two groups of 6 subjects were studied, the first received a standardized 500 kcal mixed meal without any previous drug administration (controls) whereas the second group received 50 mg indomethacin 2 h before ingesting an identical meal. Plasma indomethacin concentration reached its maximum (2.36 +/- 0.36 micro g/ml) 15 min after administration and declined to 0.45 +/- 0.04 micro g/ml after 2 h. Indomethacin ingestion was followed by a significant increase in blood glucose and plasma FFA reaching their maximum value at 45 min and returning to basal levels at 120 min. No simultaneous changes in plasma alpha-amino-nitrogen, insulin or glucagon levels were detected during this period. The meal was followed by a rise in blood glucose and plasma insulin as well as by a decrease in plasma FFA concentration. No significant differences were detected between the controls and the subjects receiving indomethacin. In controls, the meal was followed by a rise in plasma alpha-amino-nitrogen and a modest although significant increase in glucagon levels. In indomethacin-treated subjects, the increment of alpha-amino-nitrogen was less marked and the increase in plasma glucagon was not observed. Thus, indomethacin by itself can exert several metabolic effects; however, it does not deteriorate the blood glucose or insulin profile after a regular meal. The present work is the first to demonstrate that an inhibitor of prostaglandin synthesis inhibits the plasma glucagon rise occurring after a physiological stimulus such as a normal meal. On the basis of previous in vitro experiments, we suggest that this effect results from an inhibition of glucagon secretion by the PG synthesis inhibitor.

Effect of somatostatin in the Syrian hamster bearing a transplantable islet-cell tumor

The influence of somatostatin (SRIF) on blood glucose, plasma insulin and plasma glucagon was studied in hamsters bearing a transplantable islet-cell tumor secreting insulin and glucagon as well as in normal controls. Fed anesthetized animals were infused intraperitoneally either at a dose of 10 microgram in 15 min or of 150 microgram in 30 min, and intravenously at a dose of 250 microgram in 30 min. Blood was withdrawn from the jugular vein before and after infusion. Before the infusions, tumor bearing animals (TB) had lower blood glucose, markedly elevated plasma glucagon and slightly lower plasma insulin by comparison with normal hamsters (N). Both doses of somatostatin infused by the intraperitoneal route produced a slight but significant hypoglycemia in TB hamsters but not in normals. Ten microgram SRIF did not affect insulin and plasma glucagon levels whereas 150 microgram SRIF significantly depressed plasma insulin in both types of hamsters (N and TB). This latter dose of SRIF decreased plasma glucagon in normal but not in tumor-bearing hamsters. Intravenous infusion of 250 microgram SRIF did not reduce the hyperglucagonemia of TB hamsters either. These results indicate that somatostatin does not reduce the hyperglucagonemia due to the transplantable islet-cell tumor but nevertheless decreases blood glucose and plasma insulin.

Effect of bicarbonate on the arginine-induced insulin and glucagon secretion in vitro

The isolated perfused rat pancreas was used to investigate the effect of extracellular bicarbonate concentration (25 and 40 mmol/l) on the arginine-induced insulin and glucagon release with or without 5.5 mmol/l glucose in the perfusate. In the absence of glucose, the insulin response to arginine was increased at 40 mmol/l bicarbonate, while no potentiation by glucose of the arginine-induced insulin release, at this bicarbonate concentration, was observed. At 40 mmol/l bicarbonate, glucose inhibition of basal glucagon release was abolished. In contrast, the glucagon response to arginine was not affected by the bicarbonate concentration in the perfusion medium. These results confirm that the bicarbonate concentration in the medium markedly influences the insulin release from the isolated perfused rat pancreas, while the glucagon response to arginine seems to be less sensitive to changes in extracellular bicarbonate concentration.

B-cell response to a standardized breakfast in end-stage renal failure

Twelve uremic patients (U) on regular hemodialysis were submitted to a standardized test meal. In comparison with normal controls (C), U patients demonstrated a slight increase of HbA1 level and a definite elevation of fasting plasma C-peptide immunoreactivity. They showed glucose intolerance at 60 and 120 min. This was associated with an inappropriate insulin response as evidenced by a significantly lower insulin/glucose index at 60 min. U patients were tested again during a hemodialysis session in order to reduce the 60-min glucose intolerance. Six patients (U1) were selected because they exhibited mean fasting and 60-min glucose values similar to those of the controls. In these conditions, the insulin response at 60 min was significantly decreased in comparison to basal conditions and this could not be accounted for by a concomitant decrease of plasma alpha-aminonitrogen values. It is concluded that, in uremic patients, glucose intolerance is associated with an inappropriately low B-cell response.

Cardiovascular risk factors in a sample of a rural Belgian population: the Bellux MONICA Study

A sample of 1949 subjects of the population of the Belgian province of Luxembourg was screened for levels of cardiovascular risk factors. Cigarette smoking was more prevalent among males (51%) than among females (17%). The relationship between smoking and socio-economic status was inverse in males (M) and direct in females (F). Blood pressure (BP) measurements showed definite high BP in 10% of this sample, and 60% of those with definite high BP were not taking any hypertensive drugs. The average total cholesterol value was 6.49 mmol/L in M and 6.45 mmol/L in F. F had lower values than M at a younger age, but higher values than M at an older age. The high-density lipoprotein cholesterol was higher in F (1.57 mmol/L) than in M (1.27 mmol/L). Diabetes was present in 4.2% of this sample. In nearly half of these participants, the disease had been discovered during the screening. Obesity was especially frequently among F in all three age groups. In conclusion, the main cardiovascular risk factors were found to be at a fairly high level in this population sample.

Immunogenicity of semisynthetic human insulin in man. Long-term comparison with porcine monocomponent insulin

The levels of circulating IgG-insulin antibodies were determined in two groups of diabetic patients before and at 3-month intervals after starting insulin treatment either with monocomponent porcine insulin (n = 17) or with human semisynthetic insulin (SH) (n = 16). Patients were followed during 15.1 +/- 1.0 and 19.9 +/- 1.1 months, respectively (m +/- SEM). In addition, the quality of metabolic control and residual B-cell function were evaluated in the group under treatment with SHI. The percentage of patients who remained antibody-free after 12-21 months of treatment was 67.75% in the human insulin-treated group and only 25-43% in the one receiving porcine insulin (p less than 0.01). Moreover, insulin antibody titers, when present, were usually lower in subjects treated with human insulin. In SHI-treated patients: metabolic control was excellent during the first months of treatment as evidenced by values of mean daily blood glucose (7.3 +/- 0.6 mmol/l), M-index according to Schlichtkrull (7.4 +/- 2.4) and Hb1c (6.8 +/- 0.6%); residual B-cell function, evaluated at 3-month intervals by a circadian profile of plasma C-peptide did not decrease throughout the study; and a significant deterioration of blood glucose control occurred after 18 months of treatment, which might have been due to a less intensive supervision of the patients by the physicians and/or less careful attention by the patients themselves. This observation confirms the need for a continuous education of the patients regardless of the type of insulin used.

[How to explore...the metabolic syndrome by its new IDF definition]

The International Diabetes Federation recently proposed a so-called consensus definition of metabolic syndrome. According to this new definition, a subject has the metabolic syndrome if he/she has abdominal obesity (considered as a prerequisite and assessed, in the European population, by a waist circumference > 80 cm in women and > 94 cm in men) and, in addition, at least two other risk factors among 1) elevated fasting triglycerides > or = 150 mg/dl; 2) low HDL cholesterol HDL < 50 mg/dl in women and < 40 mg/dl in men; 3) increased arterial blood pressure > or = 130/ 85 mm Hg; and 4) elevated fasting plasma glucose concentration > or = 100 mg/dl. We will discuss the advantages and limitations of this new definition as well as the consequences of its use on the prevalence of the metabolic syndrome in the Belgian population.

[Non-insulin-dependent diabetes: from physiopathology to treatment]

Non-insulin-dependent (or type 2) diabetes mellitus is a common, underdiagnosed and growing disease in our society. It is responsible for increased morbidity and mortality and represents an important public health problem. This polygenic disease is often expressed late in life and its evolution is accelerated by environmental factors leading to obesity. It combines defects in both insulin secretion and insulin action, and such defects are present in various proportions according to the type of patient and the stage of the disease. Diet and physical activity recommendations are the basis of the treatment. Current pharmacological approaches aim at improving insulin secretion and/or insulin cellular action. After secondary failure to oral drugs, insulin therapy should be initiated, the patient becoming "insulin-requiring". A synergy should be searched in the combination of various therapeutic modalities in order to improve the glycaemic control.

Effects of gastroplasty on body weight and related biological abnormalities in morbid obesity

Obesity is a prevalent metabolic disorder associated with high morbidity and mortality rates. Medical treatment rarely succeeds, and bariatric surgery has been proposed as an alternative therapy. The purpose of this non-controlled retrospective study was to evaluate time-course changes in body weight in severely obese patients who underwent vertical ring gastroplasty or adjustable silicone gastric banding, and to assess the prevalence and potential reversibility of several of the biological abnormalities associated with morbid obesity. From an initial cohort comprising 658 patients, regular body weight measurements and biological data were obtained in 505 patients [419 females, 86 males; age 36 +/- 11 years; body mass index 42.7 +/- 6.9 kg/m2; (mean +/- SD)] with a mean follow-up of 26 +/- 14 months. Mean weight loss was 32 +/- 16 kg. Most weight reduction occurred within the first 6 months, followed by near-stabilisation or even slight weight regain. Most biological parameters were obtained before surgery and after at least 6 months of follow-up. The high prevalence and severity of metabolic disturbances associated with the insulin resistance syndrome (hyperglycaemia, hyperinsulinaemia, decreased HDL cholesterol, hypertriglyceridaemia, elevated fibrinogen levels and hyperuricaemia) before gastroplasty were significantly decreased after weight loss. No major biological deficiencies were observed following gastroplasty, except low iron serum levels. It is concluded that marked weight loss associated with gastroplasty involved a remarkable reduction in the prevalence and severity of several biological abnormalities classically considered as cardiovascular risk factors.

[Lack of benefit from the intermittent administration of insulin in treatment using subcutaneous perfusion pump in type 1 diabetes]

Our study is based on two constatations: 1) Hyperinsulinaemia, a possible atherogenic factor, is frequent under continuous subcutaneous insulin infusion. 2) Pulsatile intravenous insulin delivery improve the insulin's hypoglycaemic activity. To test if equivalent metabolic control can be obtained with a reduced intermittent subcutaneous infused insulin dose, we compared nocturnal metabolic control of 8 c-peptide negative type 1 diabetic patients under three experimental conditions: Continuous usual dose test (1.0 +/- 0.1 u/h); Intermittent half dose test (1.0 +/- 0.1 u/h, 30 min/h); Continuous half dose test (0.5 +/- 0.05 u/h) Five parameters were monitored: blood glucose, plasma free insulin and beta-hydroxy-butyrate, free fatty acid and glycerol plasma level. No significant differences were found between intermittent and continuous half-dose tests. We conclude that, in our experimental conditions, intermittent subcutaneous insulin infusion does not reduce the metabolic degradation induced by insulin dose reduction.

Glucagon secretion by the transplantable islet-cell tumor of the Syrian hamster

The transplantable islet-cell tumor of the golden hamster has already been shown to produce hypoglycemia and hyperinsulinemia in the receptor animal. The present study demonstrates that the plasma pancreatic glucagon concentrations are significantly increased in the tumor-bearing animals but that this hyperglucagonemia is not abolished by administration of glucose or of diazoxide. It is also unresponsive to arginine administrations. In these animals, increased peripheral glucagon plasma concentrations are observed along with a reduced porto-aortic glucagon gradient. Moreover, plasma glucagon in the vena cava is usually higher than that in the aorta and a significant quantity of glucagon is found in the tumor. We conclude that glucagon release from the tumor is in fact responsible for the observed hyperglucagonemia.

[Role of insulin and counter-regulatory hormones in the metabolic changes caused by insulin deprivation in diabetic patients]

In eight insulin dependent diabetic patients treated by continuous subcutaneous insulin infusion (1.1 +/- 0.2 U/h), the levels (measured hourly from 23 h to 05 h) of blood glucose, non esterified fatty acids (NEFA), glycerol and 3-OH-butyrate (3-OH-B) have been correlated to the circulating levels of free insulin (FIRI), glucagon, growth hormone or cortisol, in two experimental conditions: A. Insulin being infused as usual (physiological FIRI levels) and B. Progressively declining FIRI levels (insulin infusion arrested at 23 h). In condition A, blood glucose levels correlated significantly to both insulin and glucagon; NEFA, glycerol and 3OH-B correlated only to insulin. In condition B, blood glucose was significantly correlated to insulin but not to glucagon while NEFA, glycerol and 3-OH-B were significantly correlated to both hormones but not to growth hormone or cortisol. Therefore, on the metabolic deterioration that follows insulin withdrawal, growth hormone and cortisol seem to play a minor role, the main role being played by the decrease in circulating insulin levels and to a lesser extent by the increase in glucagon levels.

Effect of protein-supplemented fasting on the fuel-hormone response to prolonged exercise in obese subjects

This study aimed at investigating the influence of protein-supplemented fasting (PSF) on the tolerance and the fuel-hormone response to endurance exercise in the severely obese subject. For this purpose, eight obese men (27 +/- 2 yr, 182 +/- 7 per cent of ideal body weight) exercised on a horizontal treadmill (4 km/h) during 3 h before and after 13 d of PSF (Alburone, 70 g protein/day). Because of the 8.9 +/- 0.7 kg weight loss and the corresponding lower energy cost, exercise oxygen consumption decreased from 1.6 +/- 0.1 (before PSF) to 1.4 +/- 0.1 l/min (after PSF). In contrast, mean exercise heart rate was identical (119 +/- 5/min) in both conditions, resulting in a lower oxygen pulse after PSF. The mean respiratory quotient measured during exercise was lower after PSF (0.72 +/- 0.01 vs 0.75 +/- 0.01 2 P less than 0.05), thus demonstrating a higher fat utilization. This was supported by a higher exercise-induced plasma free fatty acid (FFA) mobilization after PSF (delta plasma FFA: + 675 +/- 101 vs + 376 +/- 121 mumol/l, 2 P less than 0.05). This metabolic adaptation mainly results from two mechanisms: a significantly lower plasma IRI at rest and during exercise after PSF (5.7 +/- 0.8 vs 11.4 +/- 1.4 microunits/ml, 2 P less than 0.001); and a lower basal blood glucose (4.2 +/- 0.2 vs 4.6 +/- 0.1 mmol/l) and an earlier decrease of glucose (30th vs 90th min) during exercise after PSF, suggesting a relative depletion of the carbohydrates stores. The lipolytic hormones (glucagon, epinephrine, norepinephrine, cortisol, growth hormone) did not significantly increase during exercise after PSF when compared to exercise before PSF; thus, their role in the enhanced FFA mobilization appears less important. Only two of our eight subjects were unable to achieve the third hour of exercise after PSF; however, no major clinical events or electrocardiographical disturbances were observed in any of the eight subjects. In conclusion, moderate exercise can be tolerated at least for 2 h during PSF when appropriate fluid, mineral and vitamin therapy is given. Under these conditions it induces a preferential utilization of fat-derived substrates and selectively augments fat mobilization which favors weight loss. For these reasons, moderate exercise can be recommended under strict medical supervision as part of all weight reduction therapy.

[How I evaluate...diabetic nephropathy. First part: micro- and macroalbuminuria]

Diabetic nephropathy (DN) appears in about 30% of patients with type 1 diabetes (D1) and 15 to 60% of patients with type 2 diabetes (D2). It is preceded by microalbuminuria. Microalbuminuria is defined as an albumin excretion rate between 30 and 300 mg/24 h (on a 24-hour urine collection) or between 20 and 200 micrograms/min (on an overnight collection) in at least two out of three consecutive collections made within a 6-month period. Alternative screening techniques use either dipstick (Micral-Test II) or the albumin to creatinine ratio on an early morning urine sample (30-300 mg/g creatinine). Once persistent microalbuminuria is confirmed, 80% of type 1 diabetic patients and 20 to 50% of type 2 diabetic patients will progress to DN. In D2, microalbuminuria also represents a powerful predictor of early mortality from cardiovascular disease. Macroalbuminuria (AER > 300 mg/24 h, corresponding to a total protein excretion > 500 mg/24 h) will eventually lead to a end-stage renal insufficiency within 10 to 20 years. In D2, numerous patients will die from cardiovascular disease before reaching end-stage renal failure. Angiotensin-converting enzyme inhibitors can slow down the evolution toward DN when prescribed when microalbuminuria appears. Screening for microalbuminuria should therefore be a part of the annual clinical assessment in every diabetic patient.

Impaired immune responses in diabetes mellitus: analysis of the factors and mechanisms involved. Relevance to the increased susceptibility of diabetic patients to specific infections

The reasons why diabetic patients present with an increased susceptibility to frequent and protracted infections remain unclear. The virtual absence of epidemiological studies of the independent risk factors involved contrasts with the multitude of in vitro models focused on the metabolism and function of immune cells from diabetic patients. This review analyzes some of these models and their clinical relevance. The different levels of diabetes pathogenesis: genetic (Type 1), autoimmune (Type 1) and metabolic (Type 1 and Type 2) are responsible for immune abnormalities demonstrated in in vitro models. The participation of genetic and autoimmune factors has been mainly characterized on T lymphocyte function. The B8 DR3 haplotype is associated with several minor immunologic abnormalities in vitro. However, the high frequency of this haplotype in healthy individuals argues against its involvement in significant defects of antimicrobial immunity. Genetic deficiency of C4, present in 25% of Type 1 diabetic patients could, on the other hand, be responsible for opsonization defects against encapsulated pathogens. Several immunological abnormalities related to the autoimmune process preceding the onset of Type 1 diabetes mellitus, such as the depletion of memory CD4+ cells and the defective natural killer activity could transiently impair host defences against viral diseases. Several in vitro functional defects of the immune system have been correlated with the metabolic control of diabetic patients. This suggests the involvement of insulinopenia in some of the abnormalities observed. Insulinopenia-induced enzymatic defects have often been proposed to inhibit energy-requiring functions of phagocytes and lymphocytes. However, the relevance of this mechanism could be confined to patients with extremely severe metabolic abnormalities. The importance of systemic consequences of insulinopenia such as hyperglycaemia and ketosis has also been addressed. Usually, the defects induced in vitro by these factors are slight and require supraphysiologic concentrations of glucose or ketone bodies. Recent studies have shown abnormalities of signal transduction mechanisms in which insulinopenia itself and other factors such as circulating immune complexes could be involved. Despite numerous controversies, many in vitro studies of the immune cells of diabetic patients have demonstrated significant defects which bear quantitative similarities with abnormalities described in other immunodeficiency syndromes. Furthermore, several mechanisms have been proposed to link the different defects observed with the specific infections encountered in diabetic patients.

The intra-nasal administration of insulin induces significant hypoglycaemia and classical counterregulatory hormonal responses in normal man

The present study aimed at investigating the metabolic and hormonal consequences of intra-nasal administration of insulin in normal man. Lyophylisated regular porcine insulin (Insuline Ordinaire Organon) diluted with a non ionic detergent (Laureth-9 0,25%) was administered intra-nasally in 8 overnight fasted healthy volunteers using a calibrated aerosol delivery device (90 microliters = 9 U of insulin/spray) up to a total insulin dose close to 1 U/kg body weight. After intra-nasal insulin administration, plasma insulin levels rose from 5 +/- 1 to 38 +/- 10 mU/l (2p less than 0.01) at min 15, blood glucose concentrations decreased from 4.4 +/- 0.2 to 3.2 +/- 0.3 mmol/l (2p less than 0.01) at min 45, plasma C-peptide levels diminished from 327 +/- 31 to 174 +/- 28 mumol/l (2p less than 0.01) at min 60 and plasma free fatty acids concentrations fell from 336 +/- 109 to 130 +/- 31 mumol/l (2p less than 0.05) at min 30. The fall in blood glucose resulted in a prompt increase in plasma glucagon levels (from 78 +/- 28 to 150 +/- 24 ng/l at min 45; 2p less than 0.05) and in later rises in plasma growth hormone and cortisol concentrations. There was a close relationship between the individual maximal decreases in blood glucose levels and the individual maximal increases in plasma insulin (r = 0.81), glucagon (r = 0.88), cortisol (r = 0.87) and growth hormone (r = 0.76) concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of insulin sensitivity by the minimal model method using a simplified intravenous glucose tolerance test: validity and reproducibility

This study aimed at testing whether 12 rather than 26 plasma glucose and insulin determinations can be used to calculate the indices of insulin sensitivity and of glucose effectiveness using Bergman's minimal model during a simple intravenous glucose tolerance test performed without tolbutamide injection. Two intravenous glucose tolerance tests (separated by 1 week) were performed in 7 lean normal subjects and a single test was performed in 9 severely obese non-diabetic subjects. Intra-subject reproducibility of insulin sensitivity was not significantly different when 26 or 12 time-points were analyzed (CV = 16.8 +/- 3.4 versus 18.9 +/- 3.8% respectively). Compared with the insulin sensitivity of the lean subjects, that of obese subjects was significantly (P < 0.001) and similarly reduced when using 12 (2.14 +/- 0.34 versus 7.97 +/- 1.29 10(-4)min-1/mU.1-1) rather than 26 determinations (2.13 +/- 0.42 versus 6.95 +/- 1.12 10(-4) min-1/mU.1-1) respectively. Glucose effectiveness was less reproducible than insulin sensitivity and was slightly diminished by the reduction of blood samples (relative error: -9.7 +/- 4.4%; P < 0.05). Finally, glucose effectiveness tended to be slightly lower in the morbidly obese subjects than in the lean controls with both modes of calculation. In conclusion, in non-diabetic subjects, the insulin sensitivity index can be accurately measured during a simple intravenous glucose tolerance test, without tolbutamide injection and with only 12 blood samples. The possibility of performing a simplified test should contribute to increase the use of the minimal model method for estimating insulin sensitivity in clinical practice.