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Biomedical subjects

M Muggeo

Publications and source records attributed to M Muggeo.

178 records · Page 10Linked to original sources
PubMedDate not supplied

Effect of aging on growth hormone, ACTH and cortisol response to insulin-induced hypoglycemia in type I diabetes.

The influence of age on plasma growth hormone (GH) response to i.v. insulin (0.2 U/kg body weight) was evaluated in clinically stable type I (insulin-dependent) diabetics divided into four age groups (range 18.80 years). ACTH and cortisol were also assayed in two groups of diabetics under and over 50 years of age. A significant reduction with aging in GH response to insulin was observed. On the contrary, the glucose fall was similar in all the groups. ACTH and cortisol responses to insulin were slightly decreased in the older diabetics. Since insulin-induced hypoglycemia was similar in all the age groups, the progressive decline with aging in the GH response to insulin may be attributed to age-related changes of the pituitary gland. The data on ACTH and cortisol are less striking. Our data, as a whole, confirm that growth hormone response to insulin-induced glucose fall is not critical in acute glucose counterregulation in insulin-dependent diabetics. In fact, in spite of a 4-fold difference in GH levels, there was no difference in the 2-h glycemic course after 0.2 U/kg of i.v. insulin between young and aged patients. When a group of 26 type I diabetics with proliferative retinopathy was compared with a group of age-matched type I diabetics without retinopathy and with 30 age-matched normal subjects (injected i.v. with 0.1 U/kg body weight of insulin), no difference was found in GH response to insulin, indicating that GH hypersecretion is not a characteristic finding of diabetic retinopathy.

Adolescent↗
PubMedDate not supplied

Bromocriptine acute effect on insulin, glucagon and growth hormone levels in acromegalic patients.

It has been shown that L-dopa or dopamine administration influences glucose metabolism, as well as insulin and glucagon release in man. In the present study, the effect of bromocriptine (CB-154), a long-acting dopamine agonist, on insulin, glucagon and growth hormone secretion in 32 acromegalic patients was investigated. Glucose, insulin and plasma glucagon levels were not modified following administration of bromocriptine or placebo. Moreover, plasma GH levels were decreased by more than 50% in 18 of the 32 acromegalics. Mean GH levels were significantly lower with respect to levels observed following placebo at 60 min to the end of the test (p less than 0.001). Administration of a double dose of CB-154 (5 mg po) one hour before arginine test did not affect insulin or glucagon secretion with respect to levels observed during arginine alone. In addition, there was a fall in GH levels similar to that observed following administration of bromocriptine alone. These findings suggest that bromocriptine in itself does not exert a direct action on insulin and glucagon release. Improvement in glucose tolerance and reduction in insulin secretion observed following prolonged CB-154 treatment in acromegalic patients are probably due to a simultaneous inhibition of GH secretion or to other peripheral effects of bromocriptine.

Acromegaly↗
PubMedDate not supplied

Plasma C-peptide response to oral glucose load in hyperthyroidism.

Aim of the present study was to evaluate the pancreatic beta cell response to oral glucose load in a group of patients with hyperthyroidism. For this purpose plasma C-peptide at fasting and after a 100 g oral glucose load was measured in 8 newly-diagnosed untreated hyperthyroid patients with fasting normoglycemia, and 8 sex-, age-, and weight-matched healthy controls. As compared to healthy subjects, patients with hyperthyroidism showed higher plasma glucose levels (incremental area 5405 +/- 742 vs 2729 +/- 539 mg/dl x 180 min, p less than 0.05), and slightly reduced plasma C-peptide concentrations (incremental area 166 +/- 12 vs 182 +/- 36 pmol/ml x 180 min, p = NS) following oral glucose load. The ratios between plasma C-peptide and plasma glucose incremental areas were lower in hyperthyroid patients than in controls (3.66 +/- 0.85 vs 10.41 +/- 3.08, p less than 0.05). These data suggest that hyperthyroidism is characterized by a decreased pancreatic beta cell response to oral glucose load.

Administration, Oral↗
PubMedDate not supplied

Plasma renin activity and urinary aldosterone in acromegaly.

The behaviour of the renin-angiotensin-aldosterone system was evaluated in 16 acromegalic patients, of whom 7 were hypertensive. The patients were studied in basal conditions, after suppression with 9alpha-fluorohydrocortisone, and after stimulation with furosemide. Baseline and after furosemide PRA were significantly lower in acromegalic hypertensive patients than in the normotensive group. Mean urinary aldosterone excretion was found at the upper limits of the normal range; it was occasionally elevated, but the values were not satistically different in the two groups. There was a suppression after 9 alpha fluorohydrocortisone in both groups, though it did not reached the 50%. These data show that there is a disorder of the renin-angiotensin-aldosterone system in acromegalic subjects. This defective regulation is sometimes similar to that present in primary aldosteronism. In fact in two patients a typical phlebographic and scintigraphic picture of primary aldosteronism has been found; surgery, performed in both patients, revealed a large cortical adenoma in one case and a macronodular hyperplasia in the second case. However, the relationship between this adrenal abnormalities and hypertension in acromegaly are not yet completely clarified.

Acromegaly↗
PubMedDate not supplied

Growth hormone response to insulin and to arginine in patients with familial hypercholesterolaemia.

Human growth hormone (HGH) response to i.v. insulin (0.1 U/kg body weight) and arginine infusion (25 g of L-arginine for 30 min) was studied in 9 patients (5 males and 4 females) with primary familial hypercholesterolaemia and belonging to 4 families. Mean age was 28 +/- 2 years (range 18-36) and body weight was less than 105% of ideal body weight. Glucose tolerance and insulin response to oral glucose were normal in all patients. HGH release after insulin and after arginine was slightly increased as compared to 21 normal controls, but the differences were not significant. Insulin and glucagon response to arginine in these patients was within the normal range. Plasma glucose and free fatty acids were normal after both insulin and arginine. Moreover, no significant correlation was found between fasting cholesterol and HGH peaks after insulin and after arginine, nor between cholesterol and insulin and glucagon responses. Despite marked hyperlipidaemia, HGH-deficient patients examined by other authors never present signs of atherosclerotic disease. Our data suggest that HGH, in the presence of elevated cholesterol levels, might play an important role in the development of atherosclerotic lesions.

Adolescent↗
PubMedDate not supplied

Effects of clofibrate treatment on arginine-induced insulin secretion in endogenous hypertriglyceridemia.

Arginine-induced insulin secretion was evaluated in 13 patients with endogenous hypertriglyceridemia (Fredrickson's Type IV) before and after a two-month period of Clofibrate therapy. Clofibrate reduced triglyceride, cholesterol and FFA levels by 68, 28 and 15% respectively and provoked a significant reduction in arginine-induced insulin secretion without modifying glucose response. Arginine-induced insulin secretion was also studied in 11 normal subjects during saline and intralipid infusions. Glucose and insulin basal values, and glucose and insulin response to arginine infusion were not influenced by Intralipid infusion in these controls. These results confirm that clofibrate reduces insulin secretion thereby contributing to decreased serum triglyceride levels.

Adult↗
PubMedDate not supplied

Effect of glipizide on insulin secretion and insulin metabolism in obese type II diabetic patients.

This study was designed to explore the short-term effect of glipizide on insulin secretion and metabolism. Plasma insulin and C-peptide levels in the fasting state and after a 100-g oral glucose load were measured in 17 obese newly diagnosed type II (non-insulin-dependent) diabetic subjects before and after 1 mo of treatment with glipizide (15 mg/day). Plasma glucose levels decreased significantly after treatment with glipizide. Plasma insulin and C-peptide concentrations in the fasting state did not change after glipizide treatment. Also, postglucose plasma insulin levels did not change after glipizide, whereas postglucose plasma C-peptide concentrations significantly increased. A significant relationship was found between the increase in C-peptide plasma levels and the decrease in glycemic profile after glucose load following glipizide treatment. The relation between plasma C-peptide and insulin incremental areas after the oral glucose load significantly increased after treatment. These results suggest that in obese type II diabetic patients, 1 mo of treatment with glipizide potentiates the beta-cell response to oral glucose load and increases insulin metabolism, probably within the liver.

Adult↗
PubMedDate not supplied

Chronobiological pattern of growth hormone secretion in normal subjects and in retinopathic diabetics. Lack of suppression by a plurichronocorticoid drug.

Nyctohemeral variations in plasma concentrations of HGH, glucose, and FFA were studied in 22 normal subjects and 48 diabetic patients affected with retinopathy. In the normal subjects, (fourteen males and eight females, mean age 40+/-3 years; body weight less than 110% of I.B.W.) the determinations were made on blood samples drawn every hour. Seven of these normal subjects were examined before and after 10 days of administration of a new plurichronocorticoid drug (administered at 08(00) and 15(00), with a total amount of 14 mg of prednisolone and 15 mg of cortisone). In patients with diabetic retinopathy (32 male and sixteen female patients, mean age 46+/-2 years, body weight less than 110% of I.B.W.) the determinations were made on blood samples drawn every 3 hrs. All the diabetic patients were insulin treated and were under good or discrete metabolic control, and presented advanced retinopathy. Both in the normal subjects and in retinopathic diabetics, the mean HGH curve showed a characteristic elevation during the early nighttime hours (between 21(00) and 02(00). Despite higher values in plasma glucose and FFA, in diabetics the nocturnal elevation of HGH was only slightly lower than in the normals. The comparison between daytime and nighttime determinations, both in the normal subjects and in the diabetics, reveals statistically significant differences. These results suggest that in subjects with diabetic retinopathy, in the phase of good or discrete metabolic control, spontaneous HGH secretion is not increased, and that nocturnal elevation of HGH is not substantially influenced by higher plasma levels of glucose and FFA. Ten days of plurichronocorticoid treatment with a new drug which exhausts its activity before the evening, did not modify the circadian rhythm of HGH.

Adolescent↗