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Biomedical subjects

V Coiro

Publications and source records attributed to V Coiro.

At least 199 records · Page 11Linked to original sources
PubMed1981

Effects of hypophysectomy and thyroidectomy on leucine metabolism in adipose tissue.

Hypophysectomy doubled the rate of oxidation of L-[1-14C]leucine to 14CO2 by segments of rat epididymal adipose tissue. Thyroidectomy, but not adrenalectomy, produced identical results. Acceleration of leucine oxidation occurred even in the presence of glucose and saturating concentrations of insulin and leucine, suggesting that thyroidectomy increased the capacity to degrade leucine. Treatment of thyroidectomized rats with triiodothyronine (T3) decreased leucine oxidation, but at least 4 days were required. Treatment of hypophysectomized rats with T3 for 6 days was ineffective unless growth hormone was also given. A similar acceleration was also seen in the rate of oxidation of alpha-keto[1-14C]isocaproate, the deaminated analogue of leucine, but neither hypophysectomy nor thyroidectomy accelerated the rate of oxidation of isovalerate, the next metabolite in the degradative sequence. These observations suggested that hypothyroidism, whether primary or secondary, might increase the activity of the mitochondrial reaction responsible for the decarboxylation of alpha-ketoisocaproate. Because thyroidectomy failed to modify the rate of oxidation of [1-14C]pyruvate that occurs by an analogue reaction and requires the same cofactors, an effect of thyroidectomy on cofactor availability was ruled out. Direct assay in a cell-free homogenate revealed a nearly twofold increase in the activity of the alpha-ketoisocaproate dehydrogenase enzyme complex. The findings support the conclusion that hypothyroidism increases the amount or activity of the mitochondrial enzyme complex responsible for decarboxylation of branched-chain alpha-keto acids.

Adipose Tissue↗
PubMed1976

Possible interaction of PGF2 alpha with hypothalamus-pituitary-thyroid axis in man.

The possible interactions of PGF2 alpha on the hypothalamus-pituitary-thyroid axis are the object of this study. Firstly a significant direct effect of PGF2 alpha infusion (mg2,5/270 min) on TSH,PRL,LH,FSH and GH pituitary secretion was excluded. Thereafter the possible PGF2 alpha on PRL and TSH pituitary response to TRH was considered: in only two cases PGF2 alpha was able to increase the TSH response. Finally the Authors studied T3 response to endogenous TSH rise induced by TRH: if they consider the mean peak responses of T3 the increase is significant only when PGF2 alpha infusion is performed.

Adolescent↗
PubMedDate not supplied

The GABAergic control of prolactin release is not affected by insulin-dependent diabetes mellitus: evidence from studies with sodium valproate.

In order to evaluate the influence of the GABAergic system in the regulation of PRL secretion in patients with IDDM, serum PRL levels were measured in 7 diabetics and in 7 normal men with sodium valproate (400 mg per os), a drug capable of increasing cerebral GABA concentrations. A significant decrease of serum PRL concentrations was observed between 30 and 120 min after sodium valproate administration in both control and diabetic subjects. The time course and magnitude of the sodium valproate effect were similar in all subjects. These data confirm the inhibitory control of the GABAergic system on PRL secretion in man as evidenced by the GABAergic drug sodium valproate. It is suggested that this system is not altered in diabetic patients.

Adult↗
PubMedDate not supplied

Effect of diet and weight loss on whole blood filterability and plasma fibrinogen values in hypertensive obese postmenopausal women.

The authors evaluated whole blood filterability (VB) in 29 post-menopausal obese women with (n = 14) or without (n = 15) hypertension, and in 22 age matched women with normal body weight. After 3 months of a low-calorie (18 kcal/kg IBW) and moderately low-salt (max 6 g NaCl/day) diet, the obese subjects were restudied. In all women plasma fibrinogen values and various indices of metabolic status were evaluated before and after the diet and correlated to VB values. VB values and plasma fibrinogen concentrations were similar in normal controls and in women with simple obesity, whereas they were, respectively, significantly lower and higher in obese subjects with hypertension. Three months of diet significantly improved whole blood filterability and decreased fibrinogen levels in these patients. Before the diet a significant negative correlation was found between VB and plasma fibrinogen values in hypertensive obese patients. Metabolic parameters did not change in the different groups before and after the diet and did not correlate with VB values. The present study indicates that low-calorie, low-salt diet decreases plasma fibrinogen levels and improves whole blood filterability in elderly obese women with hypertension.

Adult↗
PubMedDate not supplied

Possible role of glucagon in cyproheptadine-induced increase of insulin secretion.

In order to test the hypothesis that insulin secretion may be affected by increased glucagon levels during cyproheptadine (CPH) administration, an arginine-glucose test was performed in 8 normal women and repeated after three days of CPH administration at a dose of 16 mg/day. Both the glucagon and the insulin response were increased by CPH treatment and so were their incremental areas. For glucagon, the increase was present at all times tested, for insulin this rise was significant only during the first 60 min of the arginine test and during the rapid secretory phase following glucose injection. The difference between the incremental areas of glucagon before and after CPH treatment was significantly correlated to the above mentioned insulin areas and to insulin peak values. These data are in agreement with the hypothesis that in vivo CPH action on insulin secretion may be partly mediated by its effects on circulating glucagon levels.

Adolescent↗
PubMedDate not supplied

Whole blood filterability in elderly obese women.

In order to establish whether obesity alters whole blood filterability, the corrected whole blood filtration (VRBC) was measured in 54 elderly obese women (mean age +/- SE = 67 +/- 2 years) without (n = 15) or with associated cardiovascular risk factors such as impaired glucose tolerance (IGT) (n = 11), non-insulin dependent diabetes mellitus (NIDDM) (n = 14) or hypertension (n = 14). Twenty-two age matched women with normal body weight participated as controls. VRBC values were similar in normal controls and obese women with normal glucose tolerance (NGT), whereas they were significantly lower in obese subjects with hypertension, NIDDM or IGT. When subjects with normal and impaired glucose tolerance were combined, a significant negative correlation was found between glucose incretory areas during OGTT and VRBC values. These data demonstrate that obesity per se does not alter whole blood filterability; furthermore, our results indicate that this modification is a precocious and sensitive index of altered glucose metabolism.

Aged↗
PubMedDate not supplied

Effect of lysine vasopressin on basal and TRH stimulated TSH and PRL release in normal men.

In order to test the possible effects of lysine vasopressin (LVP) on basal and TRH stimulated TSH and PRL release, an iv bolus of LVP (0.06 IU/kg bw) was injected alone or just before TRH (20 or 400 micrograms iv) in 18 normal male subjects. The administration of LVP modified neither the basal secretion of TSH and PRL nor the TSH and PRL release induced by 20 or 400 micrograms TRH. These data suggest that in humans, vasopressin is not involved in the control of TSH and PRL release at the anterior pituitary level.

Adult↗
PubMedDate not supplied

Prevalence of migraine and muscle tension headache in depressive disorders.

This study was undertaken in order to evaluate the prevalence of headache and its subtypes (migraine, muscle tension headache, cluster and psychogenic headache) in a population of 160 depressed patients. Headache was present in 83 subjects (51.9%); 36 (22.5%) were affected by migraine, 39 (24.4%) by muscle tension headache, six (3.7%) by psychogenic headache and two (1.2%) by cluster headache. No significant differences in the prevalence of migraine and muscle tension headache were observed among patients with major depression, bipolar depressive disorder and dysthymic disorder. These data speak against a specific correlation among subtypes of headache and depressive disorders.

Adult↗
PubMedDate not supplied

Intravenously infused substance P enhances basal and growth hormone (GH) releasing hormone-stimulated GH secretion in normal men.

The effect of synthetic substance P (SP), infused intravenously (IV) in doses of 0.5, 1, or 1.5 pmol/kg-1/min-1 over 60 min, on GH secretion was evaluated in seven healthy men. Substance P tests and a control test with normal saline were randomly performed at weekly intervals. No untoward side effects or changes in blood pressure were observed during SP infusions. Serum GH concentrations did not change when normal saline, the lowest dose, or the middle dose of SP were infused. In contrast, GH levels rose significantly when the highest dose of SP was given, with a mean peak two times higher than baseline. Further studies were performed to test the possible influence of SP on the GH response to GH-RH. For this purpose, seven other healthy men were tested with GH-RH (1 micrograms/kg body weight in an IV bolus) during saline or SP (1.5 pmol/Kg-1/min-1 x 60 min) infusion. The GH-RH induced a significant GH rise, with a mean peak seven times higher than baseline. When subjects were infused with SP, the GH response to GH-RH was greatly enhanced, with a mean peak 12 times higher than baseline. These results demonstrate for the first time in humans that the systemic infusion of SP stimulates GH secretion, and suggest that SP might interact with GH-RH in the stimulation of GH secretion.

Adult↗
PubMedDate not supplied

Persistence of defective serotonergic and GABAergic controls of growth hormone secretion in long-term abstinent alcoholics.

In order to establish whether long-term abstinence from alcohol reverses the defective serotonergic and GABAergic controls of growth hormone (GH) secretion affecting alcoholic patients, the 5-HT1D serotonergic receptor agonist sumatriptan and the GABAergic agent gamma-hydroxybutyric acid (GHB) were administered to 12 normal men (32-49 years) and 22 non-depressed male alcoholic subjects (38-52 years) after 1-2 years of abstinence from alcohol. All subjects were also tested with placebos. Furthermore, tests with GH-releasing hormone (GHRH) and L-arginine (which releases GH from somatostatin inhibition) were performed to determine whether GH secretion in response to its major determinants is preserved in alcoholics. Administration of placebo did not change plasma GH levels in any subject. Similar GH responses were observed in normal controls and alcoholic subjects when GHRH or arginine were administered. A significant GH increase was observed in normal controls after sumatriptan or GHB injection; in contrast, GH secretion was not modified by sumatriptan or GHB administration in alcoholic patients. These data show a persistent selective loss of 5-HT1D receptor and GHB-mediated neurotransmissions in alcoholics that a long-term abstinence from alcohol is unable to restore.

Adult↗
PubMedDate not supplied

Evaluation of whole blood filterability with increasing age in healthy men and women.

Whole blood filterability, expressed as volume of red blood cells filtered per minute (VRBC), was evaluated in 53 healthy men and 56 healthy women; in each sex, subjects were divided into 4 groups according to their age: adult age (20-50 yr.), advanced adult age (51-60 yr); presenile age (61-70 yr.) and senile age (greater than 70 yr.). In addition, plasma fibrinogen, PCV, white cell and platelet total counts were measured and correlated with VRBC. Whole blood filterability and plasma fibrinogen levels were also correlated with age. VRBC and PCV decreased, whereas fibrinogen levels increased with increasing age. VRBC values showed a significant negative correlation with age and plasma fibrinogen values; a significant positive correlation was found between fibrinogen levels and age. No other examined parameter changed with increasing age nor correlated with VRBC values. These findings indicate that with aging there are modifications of some rheological parameters, such as an increase in plasma fibrinogen levels and a decrease in whole blood filterability.

Adult↗