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Biomedical subjects

O Alpi

Publications and source records attributed to O Alpi.

17 recordsLinked to original sources
PubMed1987

Relationship between blood pressure and plasma insulin in non-obese and obese non-diabetic subjects.

In this study, we have measured plasma insulin at fasting and following an oral glucose load and blood pressure after glucose load in 367 (247 non-obese, 120 obese) normotensive and untreated mildly hypertensive subjects. Overall, there was no independent association between fasting plasma insulin levels and blood pressure values. After controlling for age and body weight, a significant relationship between postglucose plasma insulin levels and diastolic blood pressure was found. When non-obese and obese subjects were examined separately, significant relationships were identified between postglucose plasma insulin levels and both systolic and diastolic blood pressure values in the former but not in the latter. A comparison of sex-, age-, and weight-matched hyperinsulinaemic vs normoinsulinaemic subjects showed that the former had significantly higher values of blood pressure only if not obese. These results demonstrate that the plasma insulin response to glucose is independently correlated with blood pressure.

Adult↗
PubMed1987

Evidence that multiple risk factors for coronary artery disease exist in persons with abnormal glucose tolerance.

Multiple risk factors for coronary artery disease were determined in 50 healthy, non-diabetic persons with an oral glucose tolerance test result that could not be classified as normal by current criteria and 50 sex-, age-, and weight-matched persons with normal oral glucose tolerance. The results indicated that persons with abnormal oral glucose tolerance were hyperinsulinemic, as well as hypercholesterolemic and hypertriglyceridemic. In addition, patients with abnormal results in glucose tolerance tests had significantly elevated systolic blood pressure and heart rates. These data suggest that a cluster of risk factors for coronary artery disease exists in non-diabetic persons with abnormal oral glucose tolerance.

Adult↗
PubMed1987

Influence of the menstrual cycle on glucose tolerance and insulin secretion.

To evaluate the impact of the menstrual cycle on glucose tolerance and insulin secretion, in the present study we have measured the plasma concentrations of glucose, insulin, and C-peptide during a 2-hour oral glucose tolerance test in 110 healthy, nonobese, regularly menstruating women. Fifty-five women were in the follicular phase, and 55 were in the luteal phase of the cycle. The two groups were well matched for age and body weight. Plasma concentrations of glucose, insulin, and C-peptide either in the fasting state or after the oral glucose load did not differ in the two groups. These results suggest that in nondiabetic women the menstrual cycle has no major effect on glucose tolerance and insulin secretion and that the phase of the menstrual cycle should not be considered in programming and interpreting an oral glucose tolerance test.

Adult↗
PubMed1986

Pathogenetic mechanisms of the endogenous hypertriglyceridemia in a nonobese rat model.

Male Sprague-Dawley IVA-SIV rats were compared to male Sprague-Dawley Charles River rats of the same age, body weight, and daily food intake. The IVA-SIV rats demonstrated hypertriglyceridemia (182 +/- 9.4 v 131 +/- 9.4 mg/dL, P less than 0.001), associated with increased fasting plasma glucose (115 +/- 3 v 84 +/- 2 mg/dL, P less than 0.001), and plasma insulin (35 +/- 5 v 19 +/- 2 microU/mL, P less than 0.001) levels. Furthermore, IVA-SIV rats responded to an oral glucose load with higher plasma glucose and insulin levels. Very-low-density lipoprotein (VLDL)-triglyceride (TG) turnover studies were performed, documenting a higher TG production rate, which correlated with the plasma TG concentrations, (r = 0.58, P less than 0.01) in the IVA-SIV rats. Since lipoprotein lipase activity in both adipose tissue and muscle was not significantly different in the two groups of rats, it appears that the hypertriglyceridemia in IVA-SIV rats is due to increased VLDL-TG secretion, associated with hyperglycemia, hyperinsulinemia, and increased plasma FFA levels. The IVA-SIV rats provide a model of endogenous hypertriglyceridemia, independent of obesity.

Adipose Tissue↗
PubMed1986

Effect of age and environmental factors on glucose tolerance and insulin secretion in a worker population.

The effect of age on glucose tolerance, as differentiated from the effects of obesity, work and leisure physical activity, family history of diabetes, and the use of drugs known to adversely affect glucose tolerance and/or insulin secretion, has been analyzed in 732 factory workers aged 22 to 73 years. Glucose tolerance, as evaluated by the plasma glucose response to 75 g of oral glucose deteriorated with age, associated with an increase in plasma insulin levels. However, the age-related decrease in glucose tolerance also correlated significantly with degree of obesity, leisure-time physical activity, and the use of potential diabetogenic drugs. Partial correlation coefficients were calculated to define the effect of age per se on glucose tolerance, controlling for the presence of these other age-related variables. When this was done, the degree of correlation between age and glucose tolerance was reduced, particularly in women, to where it became of marginal statistical significance. The effect of age on insulin response was affected to a greater degree by age-related variables, and was no longer statistically significant when these other factors were taken into consideration. These data suggest that the elevation in plasma glucose and insulin levels associated with age are to a certain extent due to age-related environmental factors, and the deterioration in glucose tolerance with age is relatively modest in magnitude in a generally healthy population.

Adult↗
PubMed1986

Insulin and C-peptide responses to 75 g oral glucose load in the healthy man.

Plasma insulin and C-peptide levels in the fasting state and after a 2-h 75 g oral glucose tolerance test (OGTT) in a large number of healthy subjects are reported. 247 volunteers (134 males, 113 females), aged 13-69 years, who had a negative history of diabetes, no history of significant disease, normal physical examination, normal body weight, normal glucose tolerance, normal blood tests, and who were taking no drugs were studied. Results, mean +/- SEM (range): fasting glucose concentration = 4.64 +/- 0.03 mmol/l (3.10 - 6.10), 1-h glucose concentration = 5.23 +/- 0.10 mmol/l (2.20 - 9.90), 2-h glucose concentration = 4.11 +/- 0.06 mmol/l (2.00 - 6.80); fasting insulin level = 0.088 +/- 0.002 nmol/l (0.03 - 0.28), 1-h insulin level = 0.45 +/- 0.01 nmol/l (0.06 - 1.63), 2-h insulin level = 0.24 +/- 0.01 nmol/l (0.05 - 1.12); fasting C-peptide concentration = 0.60 +/- 0.01 nmol/l (0.14 - 1.34), 1-h C-peptide concentration = 2.17 +/- 0.05 (0.63 - 8.56), 2-h C-peptide concentration = 1.77 +/- 0.04 nmol/(0.35 - 5.74). Fasting insulin and fasting C-peptide concentrations correlated to post-glucose insulin and C-peptide concentrations, respectively. At each sampling-point insulin concentration correlated to C-peptide concentration. After glucose ingestion, both insulin and C-peptide plasma levels correlated significantly with the corresponding glucose levels. During fasting, C-peptide but no insulin level correlated to glucose level.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Evidence for an independent relationship between plasma insulin and concentration of high density lipoprotein cholesterol and triglyceride.

Increased plasma insulin and triglycerides and decreased high density lipoprotein concentrations are primary risk factors in the development of coronary artery disease. The aim of the present study was to verify whether there was an independent relationship between plasma insulin levels and both HDL cholesterol and triglyceride in a worker population of 607 subjects, 389 men and 218 women, aged 23-73 years. An oral glucose tolerance test (75 g) was performed. Plasma glucose, insulin, triglyceride and HDL cholesterol were measured at fasting, plasma glucose and insulin were determined also 1 h and 2 h after glucose load. The results, examined separately in men and women documented a significant negative relationship between plasma insulin and HDL cholesterol level, as well as pointing out that both HDL cholesterol and insulin are significantly correlated to degree of hypertriglyceridemia, degree of obesity and level of glucose tolerance. The partial correlation coefficients between HDL cholesterol and plasma insulin levels at fasting in men and post-glucose load in women, demonstrated an independent relationship between increased plasma insulin and decreased plasma HDL concentration. However, the strongest relationship, revealed by partial correlation coefficient analysis, was between the degree of hyperinsulinemia and hypertriglyceridemia.

Adult↗
PubMed1984

Inhibition of carbohydrate-induced hypertriglyceridemia by metformin.

The ability of metformin to prevent carbohydrate-induced hypertriglyceridemia was studied in fructose fed rats. The results indicated that plasma triglycerides were approximately 50% reduced in the drug treated rats and the reduction was associated with lowered very low density lipoprotein-triglyceride secretion rates and plasma insulin levels. Since the drug does not affect the fructose intestinal absorption, it did not prevent normal rate of weight gain. These results provide further evidence for the existence of a causal relationship between plasma TG concentration and plasma insulin concentration; metformin is able to modify both these variables likely affecting primarily the ambient insulin level.

Animals↗
PubMed1984

Evidence for unimpaired pancreatic secretion and hepatic removal of insulin in healthy offspring of type 2 (noninsulin-dependent) diabetic couples.

The aim of the present study was to investigate the secretion and the hepatic removal of insulin in a group of 14 unaffected offspring of 14 type 2 (noninsulin-dependent) diabetic couples compared to 14 healthy subjects without family history of diabetes mellitus. The two groups, each consisting of 5 obese and 9 nonobese subjects, were carefully matched for sex, age, and body weight. We examined glucose, insulin, and C-peptide levels, as well as C-peptide to insulin ratios and relations during the oral glucose tolerance test. Glucose concentrations and incremental areas were similar in the two groups, as well as insulin and C-peptide levels and areas. C-peptide to insulin molar ratios, both in fasting state and after glucose load, as well as relations between C-peptide and insulin incremental areas were not different. Our results suggest that the healthy offspring of type 2 diabetic couples have a normal response of beta-cell to oral glucose as well as a normal removal of insulin by the liver.

Administration, Oral↗
PubMed1984

Peripheral hyperinsulinemia of simple obesity: pancreatic hypersecretion or impaired insulin metabolism?

Insulin and C-peptide levels in peripheral blood in the fasting state and after an oral glucose load were measured in 65 nondiabetic, obese subjects and 65 age- and sex-matched nondiabetic normal weight subjects. Fasting insulin and C-peptide levels were significantly higher in obese than in nonobese subjects, whereas 1 and 2 h after the oral glucose load only insulin concentrations were significantly higher in the obese subjects. C-peptide to insulin molar ratios, as well as the relation between the incremental areas of the two peptides, were used as relative measures of hepatic insulin extraction. In the fasting state the ratios between C-peptide and insulin were similar in obese and nonobese subjects, whereas after glucose they were significantly lower in the obese individuals. Similarly, the relations between C-peptide and insulin incremental areas were significantly lower in obese than in nonobese subjects. The comparison of the corresponding plasma levels and areas of C-peptide and insulin after glucose showed that for the same C-peptide value, the insulin value was higher in the obese group. Last, in obese subjects the parameter used as an estimate of hepatic removal of insulin after oral glucose inversely correlated with the fasting insulin concentration and the insulin incremental area after glucose. These results suggest that in obesity peripheral hyperinsulinemia depends on pancreatic hypersecretion of insulin in the fasting state and impaired hepatic insulin metabolism after oral glucose loading.

Adult↗
PubMed1984

Secretion and hepatic removal of insulin in the healthy offspring of type 2 (non-insulin-dependent) diabetic subjects.

The aim of the present study was to investigate the secretion and hepatic removal of insulin in the healthy offspring of type 2 (non-insulin-dependent) diabetic subjects. For this purpose, we examined the insulin and C-peptide responses to a 75 g oral glucose tolerance test in a group of 55 healthy subjects each having one parent with type 2 diabetes mellitus, and in a group of 55 individuals without a family history of diabetes. All the 110 subjects in the study were ambulatory volunteers, in good general health, and with normal glucose tolerance. The two groups were carefully matched for sex, age, and body weight. Glucose and insulin concentrations as well as incremental areas were similar in the two groups. C-peptide levels and incremental areas were almost identical. C-peptide to insulin molar ratios both in fasting state and after glucose load, as well as relations between C-peptide and insulin incremental areas did not differ in the two groups. In conclusion, the healthy offspring of only one non-insulin-dependent diabetic parent show a normal beta-cell response to glucose, and normal removal of insulin by the liver.

Adult↗
PubMed1982

The effect of pyridoxine-alpha-ketoglutarate (PAK) on exercise-induced increase of blood lactate in patients with type I diabetes.

Administration of pyridoxine-alpha-ketoglutarate (PAK) to a group of insulin-independent non-ketotic diabetics decreased (p less than 0.01) the plasma concentration of lactate response to isometric exercise. The mechanism of action of PAK could be interpreted as a consequence of changes induced by the drug on the Krebs' cycle with a subsequent reduction of lactate production.

Adolescent↗
PubMedDate not supplied

The response of glucose, insulin and FFA to intravenous glucose and glucagon in elderly subjects in the course of morning and afternoon tests.

The response of glucose, FFA and immunoreactive insulin to intravenous glucose and glucagon was examined in 6 apparently healthy subjects aged 67-77 years at 08(00) and 18(00) with a 3 day interval. The subjects, fasted 12 h before each test, received 0.5 g/kg of glucose i.v. and, 40 min after glucose, 1 mg glucagon i.v. The results confirmed, also in aged subjects, an impaired glucose tolerance in the afternoon test, as previously reported in the adult subject. The insulin response was delayed in the afternoon test, but the total incremental area was not significantly reduced. There was not a clearcut difference in the pattern of FFA response. The results could be a further confirmation of the central role of insulin response as a cause of impaired glucose tolerance in the afternoon also in subjects aged over 65 years.

Aged↗