Interindividual variability in the expression of surfactant protein A and B in the human lung during development.

The surfactant complex, thanks to its multiple actions including decrease of surface- tension and antimicrobial activity, plays a fundamental role in newborn survival, lowering the risk of respiratory distress syndrome. The aim of this work was to determine if the synthesis of two surfactant proteins (SP), SPA and pro-SPB, shows some inter-individual variability during lung development in the intrauterine life. Immunoreactivity for SPA and pro-SPB was investigated in the lungs of  40 subjects, including 15 fetuses, ranging from 14 to 22 weeks of gestation, and 25 neonates, from 24 to 41 weeks. Lung samples were formalin fixed, paraffin-embedded and routinely processed. SPA and pro-SPB were detected utilizing commercial antibodies.  A semi-quantitative grading system (1 to 4) was applied, based on the number of reactive cells and the intensity of immunostaining. Surfactant protein immunostaining was found in  three compartments: bronchi, bronchioles and alveoli, starting from 14 weeks of gestation in the bronchial epithelium and from the 21st week in the alveolar spaces. Differences were found regarding SPA and pro-SPB expression in the vast majority of subjects: in some lungs, SPA was more expressed whereas in others pro-SPB showed an higher degree of immunoreactivity. The expression of both surfactant proteins was not strictly correlated with gestational age. Whereas the highest levels of reactivity were detected in at term neonates, on the other hand one case with grade 3 was detected at 22 weeks and one negative case for both proteins was observed at 31 weeks. Our data clearly show a marked inter-individual variability regarding the production of SPA and pro-SPB and suggest the existence of other epigenetic factors, acting during gestation, that might influence surfactant production and, consequently, the survival potential of  neonates at birth.

Low-density lipoproteins are more electronegatively charged in type 1 than in type 2 diabetes mellitus.

Multifactorial etiology is involved in premature atherosclerosis related to diabetes. Most of the mechanisms that are responsible for the etiology in diabetes have remained unsolved so far. Type 1 diabetes is associated with a favorable lipid pattern and with microangiopathy, which is not true for type 2 diabetes, which is related to dyslipidemia and macroangiopathy. The aim of this work was to evaluate the degree of LDL modification related to the types of diabetes. The question is whether the LDL could be differently modified since the pathogenesis of type 1 and type 2 diabetes is different. Thirty-one type 1 (19 male and 12 female) and thirty type 2 (18 male and 12 female) diabetic patients were included in this study. Isolated LDL was analyzed by capillary electrophoresis for diene conjugate content and for electronegativity. LDL from type 1 diabetes subjects showed the highest electrophoretic mobility (P = 0.000). Instead, the diene conjugates contents were higher in the type 2 patients with HbA1c levels > 8% (P = 0.007). In conclusion, the increased diene content in type 2 diabetic subjects in poor glycemic control and the highest LDL mobility found in type 1 subjects show that the LDL undergoes different modifications. In type 2 patients, electronegative LDL are in a state of higher susceptibility to oxidation, whereas in type 1 subjects the finding of electronegative lipoproteins could provide an index of the relative atherogenicity of circulating LDL, especially as LDL has higher electrophoretic mobility than normal subjects.

In vivo oxidizability of LDL in type 2 diabetic patients in good and poor glycemic control.

We aimed to determine if increased non-enzymatic glycosylation of the LDL was sufficient to increase the susceptibility to in vivo oxidation of the LDL particles. Twenty-two type 2 diabetic patients (11 males and 11 females) were included in this study. They were enrolled on the basis of good [glycated hemoglobin (HbA1c) < 7%] and poor glycemic control [(HbA1c) > 8%]. LDL were isolated by sequential ultracentrifugation and analyzed by capillary electrophoresis (CE) for diene conjugate content and for electronegativity. The glyc-LDL levels were increased in all diabetic type 2 patients, peaking in the diabetic subjects in poor diabetic control (17.3 +/- 8.07%). The LDL content of diene conjugates was similar between the two groups (6.65 +/- 0.77% for the patients with good glycemic control versus 6.88 +/- 0.74% for those with poor glycemic control; P = 0.49) as was the electrophoretic mobility ((-1.14544 +/- 0.089) x 10(-4) cm2/(V s) for the patients with good glycemic control and (-1.13666 +/- 0.073) x 10(-4) cm2/(V s) for those with poor glycemic control; P = 0.80). The susceptibility to in vivo oxidation of LDL from type 2 diabetic patients in poor glycemic control did not differ from that of well-controlled diabetic patients. LDL glycosylation was not able to increase the oxidizability of LDL in the diabetic patients with poor glycemic control.

Low adherence of General Practitioners to National Cholesterol Education Program guidelines for the management of hyperlipidaemia.

Aim of our study was to assess adherence to the National Cholesterol Education Program Adult-Treatment Panel II (NCEP-ATP II) in patients cared for by General Practitioners (GPs) in an Italian community. The design of the work was cross-sectional cohort study; the base was an unselected cohort of 1,168 patients cared for by GPs and screened at our lipid clinic in 1994-1995 in the Province of Turin (Italy). Blood samples were collected after 12-hr fast to measure plasma levels of total cholesterol, triglycerides, HDL-cholesterol, glucose and thyroid-stimulating hormone (TSH). LDL-cholesterol was calculated using Friedewald's formula. In patients with body mass index (BMI) >30 kg/m2, an oral glucose tolerance test was performed. Blood pressure was measured in all patients, and a baseline ECG or a stress test was performed in those with unknown cardiovascular disease (CVD), then they were classified following the NCEP-ATP II criteria. Primary hyperlipidaemia accounted for 86.9% of the cohort with most patients requiring pharmacological treatment; in 34.4% of the patients, LDL-cholesterol values were > or = 6.46 mmol/l (250 mg/dl) and in 23.7% with established CVD, LDL-cholesterol levels were > or = 5.68 mmol/l (220 mg/dl). In only 7.3% of patients the NCEP treatment goals were achieved, with 1.3% among those in secondary prevention. We observed great discrepancies between clinical practice and international recommendations for the management of hyperlipidaemia.

Sex differences in incidence of IDDM in age-group 15-29 yr. Higher risk in males in Province of Turin, Italy.

OBJECTIVE: To report the incidence of IDDM in the age-group 0-29 yr in the Province of Turin, Italy (951, 445 inhabitants 0-29 yr of age), over a 5-yr period (1984-1988) according to age, sex, and geographical region within the area and to identify any temporal trend. RESEARCH DESIGN AND METHODS: The survey used as the primary data source the list of all patients attending diabetic clinics, and as secondary data source, used the list of hospital discharges for diabetes. RESULTS: We identified 298 incident cases of IDDM in people 0-29 yr of age. Estimated completeness of ascertainment of the registry was 97%. Age-adjusted (world-standard) incidence rates were 7.40/100,000 (95% CI 6.28-8.71), 5.83 (4.95-6.86), and 6.70 (5.97-7.51), respectively, in the age-groups 0-14, 15-29, and 0-29 yr. Incidence was significantly higher in males than in females in the age-group 15-29 yr (7.36, 6.02-8.98, vs. 4.21, 3.12-5.56). An increasing incidence from rural areas to the greater Turin area (city and its industrial belt) was evident. No significant temporal trend during the study period was found, although year-to-year variability was evident, with the highest incidence in 1984. CONCLUSIONS: This study suggests a high male-to-female ratio of incidence of IDDM after 14 yr; either sex hormones or different exposure to environmental determinants could be involved.

Use of premixed insulin among the elderly. Reduction of errors in patient preparation of mixtures.

OBJECTIVE: To evaluate the accuracy of elderly patients in their mixing of regular and intermediate insulins, to assess the safety and efficacy of premixed insulins compared with extemporarily mixed insulins, and to determine patients' preferences. RESEARCH DESIGN AND METHODS: We conducted a crossover multicenter study of 5 mo duration. Premixed insulins and patient-mixed, human biosynthetic (rDNA) insulins were used among 64 insulin-treated patients with NIDDM. After a 4-wk run-in period, eligible patients were randomly assigned to treatment 1 (extemporarily mixed insulins) or treatment 2 (premixed insulins) for 8 wk. After that period, the two treatments were crossed for an additional 8-wk period. A blood glucose profile was recorded monthly and HbA1c was measured at the beginning and at the end of each treatment period. An in vitro skills test was performed to assess the accuracy and reproducibility of the patient preparation of insulin doses, and a questionnaire was used to determine their personal preferences for premixed versus extemporarily mixed insulin. RESULTS: In our study, the quality of the metabolic control was the same whether patients used self-mixed or premixed insulin. The differences in blood glucose profiles and HbA1c were negligible between type and periods of treatment. The overall number of hypoglycemic episodes increased during the trial in both groups, but the difference between treatments was not significant. The in vitro skills test, however, indicated that the accuracy in the preparation of insulin doses was significantly higher when patients aspirated from one vial compared with preparation from two vials (P < 0.001). The CVs were 3.7% when drawing up a single dose and 5.0% when preparing a mixture, but the ranges were rather elevated (0.1-20.7 and 0.6-35.8%, respectively). Forty-two patients described the preparation of their daily insulin dose as very easy and 21 described it as easy when using premixed insulins versus 11 and 43, respectively, when using extemporarily mixed insulins (P < 0.001). CONCLUSIONS: While the quality of the metabolic control was the same whether patients used self-mixed or premixed insulin, the in vitro skills test indicated that insulin preparation by elderly patients is highly inaccurate. In some patients, a modification of the contents of the insulin is likely to occur in a few days. The use of premixed insulins should lessen the errors that occur in mixing insulins and from the contamination of the second insulin vial. Draw-up errors could partially account for the lack of improvement of glucose control during the period when patients received premixed insulins. A longer observation period probably is needed to assess appreciable changes in the quality of diabetes control.

A population-based prevalence survey of known diabetes mellitus in northern Italy based upon multiple independent sources of ascertainment.

The aims of this survey were (1) to estimate the prevalence of known diabetes mellitus in 1988 in Casale Monferrato (Northern Italy); (2) to validate different data sources available in Italy; (3) to identify a population-based cohort of diabetic patients. Multiple independent data sources were used and the capture-recapture method was applied to estimate the completeness of ascertainment of the survey. The primary data source was the list of all patients attending the diabetic clinic or those referred by family physicians and paediatricians of the area. The secondary data sources were the list of hospital discharges, the prescriptions data source and the list of all people using reagent strips and insulin syringes. On 1 October 1988 (the cut-off date) 2,069 cases of known diabetes were identified. The estimated completeness of ascertainment of the survey was 91%. Prevalence of known diabetes, Type 1 (insulin-dependent), Type 2 (non-insulin-dependent) and insulin-treated diabetes were, respectively, 2.21% (95% CI 2.13-2.29), 0.80/1,000 (0.62-0.98) and 2.10% (2.01-2.19), 2.92/1,000 (2.57-3.27). A higher prevalence of Type 2 diabetes was observed in women (2.30%, 2.18-2.42) than in men (1.88%, 1.76-2.00). Age-specific prevalence of Type 2 diabetes increased with age. Computerized data sources routinely available in the Piedmont Region (hospital discharges and prescriptions data sources) showed a low completeness of ascertainment when considered together (65%, 1,338 of 2,069), indicating the need to involve the diabetic clinic and family physicians in the ascertainment of known diabetes. In conclusion, the prevalence of known diabetes in Italy was lower than in Northern Europe and the United States.

Comparison of the metabolic effects of mixed meal and standard oral glucose tolerance test on glucose, insulin and C-peptide response in healthy, impaired glucose tolerance, mild and severe non-insulin-dependent diabetic subjects.

Dietary constituents other than glucose can influence insulin secretion in non-insulin-dependent diabetes mellitus and administration of a standard mixed meal has been proposed as a more physiological test in regard to human diet for evaluating the patient both at the time of diagnosis and during follow-up. This study was carried out to compare the effects of a standard meal and the oral glucose tolerance test on glucose, insulin and C-peptide plasma levels in four groups of subjects: healthy controls, subjects with impaired glucose tolerance, patients with mild non-insulin-dependent diabetes, and non-insulin-dependent diabetic patients with secondary failure to oral agents. Plasma glucose values were significantly higher after the oral glucose tolerance test than after the mixed meal in all four groups of subjects. Plasma insulin and C-peptide values were similar during the two tests in all groups of subjects except in non-insulin-dependent diabetics with secondary failure (flattened curves). Insulin and C-peptide responses per unit rise in blood glucose were significantly higher after the oral glucose tolerance test than after the mixed meal both in mild non-insulin-dependent diabetics (P less than 0.05 and P less than 0.05) and in non-insulin-dependent diabetics in secondary failure (P less than 0.01 and P less than 0.05). There was significant correlation between oral glucose tolerance test and mixed meal glucose incremental areas (r = 0.511, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin supplement in type 2 diabetic patients with secondary failure to oral agents ameliorates hepatic and peripheral insulin sensitivity but not insulin secretion.

In order to investigate the mechanism of amelioration of metabolic abnormalities with supplementary doses of insulin, islet B-cell function and insulin sensitivity were measured in 10 patients with Type 2 diabetes in secondary failure to oral agents. A small dose of ultralente insulin (0.26 +/- 0.07 U kg-ideal-body-weight-1) was added in the morning before breakfast. After 3 months insulin therapy and progressive improvement of metabolic control (HbA1 from 10.5 +/- 0.4 to 9.0 +/- 0.3% at the end of insulin treatment, p less than 0.001), basal C-peptide and incremental area during an oral glucose tolerance test were unchanged. In vivo peripheral insulin sensitivity (euglycaemic clamp with insulin infusion of 40, 160, and 600 mU m-2 min-1, respectively) was significantly improved (glucose requirement: to 4.7 +/- 1.0 from 3.0 +/- 0.6 mg kg-1 min-1, p less than 0.05 at first insulin level; to 10.8 +/- 0.5 from 9.3 +/- 0.7 mg kg-1 min-1, p less than 0.01 at second level; to 13.3 +/- 0.6 from 11.8 +/- 0.8 mg kg-1 min-1, p less than 0.025 at third level). Basal hepatic glucose production was also significantly reduced (from 4.3 +/- 0.4 to 3.3 +/- 0.3 mg kg-1 min-1, p less than 0.05), and residual glucose production further suppressed after insulin supplement (from 1.1 +/- 0.4 to 0.3 +/- 0.2 mg kg-1 min-1 after 120 min at 100 mU l-1 plasma insulin, p less than 0.05). Specific insulin binding to mononuclear leucocytes was unchanged (from 3.1 +/- 0.3 to 3.5 +/- 0.3%, NS).

Incidence of IDDM during 1984-1986 in population aged less than 30 yr. Residents of Turin, Italy.

The goal of this study was to measure the incidence of insulin-dependent diabetes mellitus (IDDM) during 1984-1986 in residents of Turin, Italy, aged less than 30 yr. The primary data source was the list of all subjects diagnosed with IDDM who attended diabetes clinics in Turin. Other data sources were the general register of death certificates, the list of hospital discharges, and the computerized data base of insulin prescriptions. Eighty incident cases of IDDM were identified during the study in 1,130,284 person-yr for those less than 30 yr of age. Age-adjusted (world standard) incidence rates were 8.05, 8.10, and 6.96/100,000 in the age-groups 0-14, 0-19, and 0-29 yr, respectively. Estimated completeness of the primary data source compared with all other data sources was 91%, whereas the estimated completeness of ascertainment of the registry was 99%. Incidence rates of IDDM in northern Italy compare with those of European countries with low-medium incidence. A population-based register is being established for the province of Turin (951,445 inhabitants aged 0-29 yr) for the collection of incident cases since 1984.

Univariate and multivariate analysis of associated factors of retinopathy in 894 Italian adult diabetics.

The prevalence of diabetic retinopathy and the evaluation of its risk factors is poorly known in Italian population. Therefore, we have studied 894 diabetic outpatients (420 males, 474 females, 27.6% IDDs, 38.1% insulin-treated) in order to investigate the effect of clinical and metabolic characteristics on the frequency of diabetic retinopathy, classified into six different classes. In univariate analyses age, duration of disease, systolic and diastolic blood pressure, blood urea nitrogen, 24 hr proteinuria and fasting glycemia significantly correlated (p less than 0.001) with severity of retinopathy. The significance was confirmed in multivariate analysis for duration, age and systolic blood pressure (p less than 0.001). Stratification by type of diabetes showed that undefined onset of diabetes probably reduced in NID patients the power of duration as an associated factor of retinopathy. Worsening of this complication in three clinical classes of therapy (diet, oral and insulin-treatment) is evident too. Finally, our 11 variables in the step-wise multiple-regression analysis explain only 16.8% of diabetic retinopathy in all patients, but 36.6% in selected ID subjects.

Insulin secretion and insulin sensitivity defects are a common feature of mild, clinically homogeneous, recently diagnosed type II (non-insulin-dependent) diabetics.

Alteration in insulin secretion and reduced peripheral sensitivity to the hormone have been reported in type II diabetes. In this paper, a comparison is made of basal glucose production (3H-6 glucose), insulin secretion and insulin sensitivity in vivo (hyperglycemic clamp) and in vitro (binding to circulating monocytes) in 24 patients with recently diagnosed type II diabetes, matched for age and fasting glycemia and divided into non-obese (14 subjects) and moderately obese (10 subjects), and in 9 non-obese controls. The non-obese diabetics were slightly hyperinsulinemic during fasting (10.8 +/- 1.0 vs 4.8 +/- 0.8 microU/ml in controls, p less than 0.0005), with a significant reduction in early and late insulin secretion (14.0 +/- 1.5 vs 20.8 +/- 2.0 microU/ml, p less than 0.01 and 24.8 +/- 3.3 vs 34.7 +/- 2.14 microU/ml, p less than 0.025). The insulin sensitivity index MCR/I was significantly reduced (2.30 +/- 0.32 vs 4.14 +/- 0.40, p less than 0.005). Endogenous glucose production was significantly increased (107 +/- 10.2 vs 84 +/- 3.7 mg/m2 per min, p less than 0.025) and displayed a positive correlation with fasting glycemia (r = 0.51, p less than 0.05). Insulin binding to monocytes was significantly lower than in controls (2.36 +/- 0.22% vs 4.06 +/- 0.32%, p less than 0.0005). Moderately obese diabetics also were significantly hyperinsulinemic in the fasting state (18.1 +/- 2.8 microU/ml, p less than 0.0005 vs controls) but, typically, lacked the early secretory phase (20.6 +/- 3.6 microU/ml vs baseline, n.s.). A similar increase of hepatic glucose production (107 +/- 11.2 mg/m2 per min, p less than 0.025 vs controls, n.s. vs non-obese diabetics) and decrease of peripheral sensitivity to insulin (MCR/I = 1.78 +/- 0.31, p less than 0.0005 vs controls, n.s. vs non-obese diabetics) was found in moderately obese diabetics, as well as a significant reduction of insulin binding to insulated monocytes (2.62 +/- 0.4% p less than 0.01 vs controls, n.s. vs non-obese diabetics). These results confirm that common defects of both non-obese and moderately obese type II diabetics are: lack of early phase of glucose induced insulin secretion, increase in hepatic glucose production and decrease of peripheral insulin sensitivity together with reduction of insulin binding to circulating monocytes. The hypothesis of a unique defect as a cause of hyperglycemia in type II diabetes in early clinical phase is not borne out by the results of this study. Moderate obesity, even if able to reduce insulin sensitivity, seems to be less important in determining hyperglycemia.

Moderate guar-gum addition to usual diet improves peripheral sensitivity to insulin and lipaemic profile in NIDDM.

The addition of vegetable fibres to the diabetic diet has been reported to ameliorate glycaemic and plasma lipid profiles, and Guar flour seems to obtain the best results. At its usual dose, Guar produces several gastro-intestinal side effects. A lower dose (4 + 4 g/day) was therefore employed in 10 non-insulin dependent diabetics (NIDD). The following parameters were measured at the end of treatment and after a control period: HbA1 levels, hepatic glucose production (3H-Glucose infusion), peripheral sensitivity to insulin and insulin secretion (hyperglycaemic clamp), and specific insulin binding to isolated monocytes. The ultracentrifugal plasma lipid pattern was also measured. No significant body weight change was recorded during the study. A significant glycaemic and insulinaemic decrease in the fasting state was observed after Guar, together with a significant decrease of HbA1 levels (from 8.5 +/- 0.4 to 7.9 +/- 0.4%, p less than 0.05) and amelioration of peripheral sensitivity to insulin (M/I = 14.3 +/- 6.6 versus 24.3 +/- 8.8, p less than 0.025; 50% increase of insulin binding to circulating monocytes) without significant variation of the fasting hepatic glucose production. Decreased B-cell stimulation by flattening post-prandial glycaemic peaks may be an explanation of the reduction of insulin resistance via down-regulation mechanism. As far as the lipid profile is concerned, a significant reduction in total and LDL cholesterol (p less than 0.05 and p less than 0.01) and an increase in HDL-phospholipids (p less than 0.05) were recorded after Guar. These results suggest that Guar in low doses is well accepted and can contribute to a better glycaemic and lipaemic control in NIDDM.

Hyperglycaemic clamp and insulin binding to isolated monocytes before and after glibenclamide treatment of mild type II diabetics.

The therapeutic action of 3.5 mg glibenclamide (HB 420) once a day for six weeks was evaluated in ten mild NID diabetics previously treated with diet only. Stable HbA1, insulin secretion during hyperglycaemic clamp (100 mg/dl over the baseline in the first study, and at the same level in the second one), peripheral sensitivity expressed as the amount of dextrose infused per Kg per min (M-coefficient), the glucose metabolic clearance rate (MCR) and the M/I ratio were measured. Circulating monocytes were separated to assess insulin binding before and after treatment. The results included a significant decrease in HbA1 (7.5 +/- 0.3 against 8.4 +/- 0.4%, P less than 0.005), increased steady-state (100-120 min.) plasma insulin (31 +/- 4.4 against 25.7 +/- 3.9 microU/ml), a significant increase in M-coefficient (4.02 +/- 0.62 against 2.49 +/- 0.31 mg/Kg/min, P less than 0.01), and MCR (1.90 +/- 0.34 against 1.18 +/- 0.18 ml/Kg/min, P less than 0.025) and an increase in the M/I ratio (14.6 +/- 1.9 against 11.2 +/- 1.7). All subjects displayed an increase in total insulin binding (4.03 +/- 0.31% against 2.79 +/- 0.34%, P less than 0.001) and affinity constants (Ke = 8.3 +/- 0.6 against 6.6 +/- 0.4 X 10(7) M-1, P less than 0.05). Since the M/I ratio increased in only 7/10 subjects and since there was no significant correlations between the percentage increase in M and MCR and the plasma insulin increase, whereas the increase in R0 was significant, it is felt that the euglycaemizing action of low doses of glibenclamide is primarily peripheral.(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin resistance in the aged: the role of the peripheral insulin receptors.

In the healthy subject, glucose tolerance tends to decrease with age due to impaired insulin secretion and/or decreased peripheral insulin activity. An oral glucose (100 g) tolerance test was performed on 12 aged (70 +/- 4 yr) and 8 young (32 +/- 7 yr) subjects; these subjects underwent laparatomy for cholecystectomy or the management of abdominal diseases. Subcutaneous adipose tissue was removed during surgery and fat cells, prepared according to a personal modification of Rodbell's method, were incubated in a medium containing monoiodo- and cold insulin to evaluate insulin binding and affinity constants. The results of the tolerance test pointed to an insulin resistant state i.e., impaired glucose tolerance coupled with normal plasma insulin, as previously shown also by us using other methods in the aged subject. The binding study demonstrates a distinct insulin receptor decrease in fat cells from the older subjects (185,000 +/- 19,200 as opposed to 310,000 +/- 12,000), without any change in affinity constants. The result indicates that insulin resistance in the aged may be attributed at least in part to a reduction in the number of insulin receptors on the target cells. This could be a consequence of aging itself, as proposed by other workers in the case of old fat rats.

Diurnal variations in insulin secretion and insulin sensitivity in aged subjects.

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 07(00) and at 19(00) 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 aging 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.

Metabolic and hormonal changes during exercise in healthy, diabetic and obese subjects.

The metabolic and hormonal changes during a standard physical exercise were studied in healthy subjects and in insulin-dependent diabetics well matched for body weight, and therefore submitted to a similar work load in a physiologic range, and in obese subjects that, owing to their weight, faced a significant heavier work in the same environmental conditions. Moderate work load did not lead to significant changes in metabolic and hormonal blood parameters (blood glucose, FFA and glycerol; insulin, glucagon, growth hormone and cortisol) in healthy subjects. A similar substrate homeostatis was seen in insulin-dependent diabetics, that however showed marked hormonal alterations. In these subjects, indeed, higher levels of plasma glucagon and GH were reached during work and in the recovery phase. Obese subjects, submitted to a heavier work load, presented a marked increase in blood glucose and glycerol which agrees with high GH and cortisol levels, and a subsequent increment of IRI which corresponds to a normalization of blood glucose and glycerol. Obese subjects, therefore, show a normal sensitivity to work load. Considerations about the work load in everyday life are discussed.