Endocrine profile and therapeutic employment of a new prolactin-lowering drug, metergoline.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to C Ferrari.
Explore the source record for details and available documents.
It has recently been claimed that the PRL-lowering response to nomifensine administration (200 mg, orally) reliably discriminates patients with PRL-secreting tumors from those with so-called functional hyperprolactinemia. In the present study, this test was performed in 15 healthy controls, 7 hyperprolactinemic subjects without evidence of pituitary tumor, and 16 patients with prolactinoma. A decrease of serum PRL to below 65% of basal levels, which seemed to be the cut-off point in the previous study, was obtained in 11 subjects of the first group, in 4 subjects of the second group, and in 4 subjects of the third group. The decrease of mean serum PRL concentration after nomifensine was only significant in the first and second groups. Analysis of variance showed a significant difference in the PRL inhibition by nomifensine between the tumor group and the two groups without evidence of pituitary adenoma. Nevertheless, this study shows that the nomifensine test is unable to discriminate in the individual patient the tumorous or nontumorous origin of excessive PRL secretion.
Explore the source record for details and available documents.
The effect of 1 week of oral treatment with four antidopaminergic drugs--metoclopramide, sulpiride, haloperidol, and pimozide--on fasting and meal-stimulated serum gastrin levels has been evaluated in healthy subjects. All of the four drugs significantly reduced the gastrin response to a meal, whereas basal concentration was unaffected. It is suggested that this action is mediated by central nervous system dopamine receptor blockade, which might act either via nervous or humoral mechanisms to inhibit gastrin release.
The effects of some imidazole derivatives, H2-antagonists and H2-agonists, with different alkyl groups in 5-position (R = Me, Et, i.Pr), were studied comparatively on cat gastric secretion and guinea-pig gastric fundus. The antagonistic and agonistic activities decrease with increase in the substituent inductive effect, and, in particular, it should be noted that the cimetidine ethyl analog (compound V) is a competitive antagonist of H2-histamine receptors. More hypotheses on the H1- and H2-receptor surfaces are proposed.
The distribution of normal intestinal flora changes in the different gut segments and is influenced by gastric pH, peristalsis, bactericidal activity of Immunoglobulins A (locally produced). Saprophytic bacteria prevent the growth of pathogenous microorganisms, partake in the production of vitamins (K, B group), can be responsible for the production of carcinogens and co-carcinogens by acting on bile-acids, food or drugs ingested, can affect the morphology of the intestinal mucosa. Enteroviruses are transient intestinal microorganisms, responsible for infectious disease whose highest incidence is summer and autumn, whose frequency is particularly elevated in malnourished subjects.
The most recent data concerning the characteristics of hepatitis A virus, as well as epidemiology and prophylaxis of type A hepatitis are described. An epidemic of hepatitis A which occurred in a village near Parma is analysed. The diagnosis was based on the detection, by radioimmunoassay, of specific antibody to hepatitis A antigen (anti-HAV) at the beginning of the infection and during the convalescence. In addition the occurrence of high levels of specific immunoglobulins type M anti HAV, during the acute phase, was a further evidence of the diagnosis. The presence of other agents responsible for acute hepatitis, such as Cytomegalovirus and Epstein-Barr virus, has been excluded by laboratory examination.
The effects of oral administration of the anti-inflammatory drug, (Z)-5-fluoro-2-methyl-1-[p-(methylsulfinyl)-benzylidene]-indene-3-acetic acid (sulindac, Clinoril) 400 mg/d for 8 days, on basal and submaximal (3 micrograms/kg b.2. i.m.) and maximal (6 micrograms/kg b.w.) pentagastrin-stimulated gastric acid secretion as well as on serum gastrin concentration have been evaluated in female patients affected with osteoarthrosis. No significant changes in either gastric acid or gastrin secretion were induced by the treatment. Serum gastrin levels were also unaltered after acute administration of 200 mg sulindac. These results confirm and extend previous observations suggesting that the drug does not exert major actions on the stomach.
Explore the source record for details and available documents.
The effects of acute clonidine infusion (0.15 mg over 10 min) on several endocrine and metabolic variables have been evaluated in 12 hypertensive patients and 12 normotensive controls. Plasma glucose increased significantly in comparison with a placebo study in both groups; serum growth hormone showed a significant increase in healthy subjects but did not rise in hypertensive patients; there was no correlation between the increments in plasma glucose and in serum growth hormone in the whole group of subjects; serum-free fatty acids, insulin, prolactin and plasma cortisol did not change in any group. These data, although not excluding a central site of the clonidine hyperglycemic action, contrast the view that it may depend on stimulation of growth hormone release.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The effects of short-term treatment with either placebo or two serotonin antagonists, cyproheptadine and metergoline, on oral glucose tolerance and insulin secretion have been evaluated in normal subjects and in patients with chemical diabetes. Placebo treatment was not associated with any significant change in the parameters examined. Glucose tolerance in chemical diabetics was significantly improved both after cyproheptadine and metergoline; fasting plasma glucose was also reduced by metergoline. Treatment with the latter drug was also associated with a significant decrease in incremental glucose area in healthy subjects, which was not affected by cyproheptadine. Basal and glucose-stimulated insulin secretion were not affected by either drug in any subjects. Cyproheptadine and metergoline improve glucose metabolism in chemical diabetes probably by reducing insulin resistance. This may depend either on decreased secretion of counter-regulatory hormones or on a direct pharmacological action of the drugs on glucose utilization, possibly mediated by their common antiserotoninergic properties.
In an attempt to identify the sites at which cimetidine stimulates prolactin release, the drug was administered intravenously (6 mg/kg body weight) to healthy subjects under basal conditions, during dopamine infusion (1 microgram/Kg-min for 120 min) and after pretreatment with L-dopa plus carbidopa (250 plus 25 mg every 6 for 1 day). The serum prolactin response to cimetidine was abolished by dopamine infusion and almost completely suppressed by L-dopa plus carbidopa administration. These findings suggest that the drug acts on the central nervous system to stimulate prolactin release. Although the mechanism of this action is unclear, it does not seem to depend on an antidopaminergic effect and may be related to blackade of brain H2 histamine receptors.
Unexplained cardiomegaly with cardiac failure was observed in a 42-year-old woman in whom a pituitary tumour had been treated by radiotherapy five years previously. She had been amenorrhoeic for 10 years. Thyroid and adrenal function was normal. Despite treatment with digitalis and diuretic, her cardiac disease progressed until she died suddenly at the age of 45. Hyperprolactinaemia was evident some weeks before death, her serum concentration of 68 ng/ml being well above both the reported normal range (2--20 ng/ml) and the concentrations in eight female controls being treated for severe cardiac failure (5--25 ng/ml). Although the association of these two disorders might merely represent coincidence, heart disease with similar features is common in acromegaly and does not correlate with plasma growth hormone concentration. Since prolactin is known to exert metabolic growth hormone-like effects in animals and in man, the possibility should be considered that prolactin hypersecretion might induce or maintain cardiac disease in some patients with pituitary tumours. A preliminary survey of 35 subjects with hyperprolactinaemia has shown five with raised blood pressure and four, two of whom were normotensive, with cardiomegaly on chest radiography.
Explore the source record for details and available documents.
TSH concentration was measured in plasma before and after TRH administration (200 micrograms, iv) in 89 patients with documented hypothyroidism consequent to various hypothalamic-pituitary disorders. Basal plasma TSH was less than 1.0 microI/ml in 34.8%, between 1.0-3.6 microU/ml in 40.5% and slightly elevated (3.7-9.7 microU/ml) in 24.7% of the cases. The plasma TSH response to TRH was absent in 13.5%, impaired in 16.8%, normal in 47.2%, and exaggerated in 22.5% of the cases, with delayed and/or prolonged pattern of response in 65% of the cases. The dilution curves of several plasmas drawn before and after TRH were parallel to those obtained with TSH standard preparation. After gel filtration, the elution pattern of TRH-stimulated plasmas from 4 patients did not show any major difference from that of pooled plasmas from normal subjects given TRH or from that of patients with primary hypothyroidism. Plasma TSH values determined by cytochemical bioassay on both basal and TRH-stimulated samples of 5 patients were markedly lower than those obtained by RIA. The serum T3 response to TRH was absent or low in 40 out of 53 patients in whom it was evaluated. The administration of T3 (100 micrograms/day for 3 days) or dexamethasone (3 mg/day for 5 days) respectively suppressed or reduced both basal and TRH-induced plasma TSH levels. Two patients became hypothyroid shortly after pituitary surgery in spite of basal and TRH-induced plasma TSH levels similar to or higher than those before surgery. Though thyroid atrophy due to chronic understimulation could explain the low T3 response to TRH in secondary hypothyroidism, it is difficult to reconcile thyroid understimulation with normal or increased plasma TSH unless the immunoreactive material has low biological activity. Present data suggest that several patients with hypothyroidism consequent to hypothalamic-pituitary diseases secrete a material which is immunologically similar to pituitary standard TSH and responds to stimulatory and suppressive agents in a manner similar to normal TSH but has low or absent biological activity. Thus, hypothyroidism due to insufficient TSH stimulation can be termed central hypothyroidism and can be due 1) to pituitary insufficiency (secondary hypothyroidism), 2) to a hypothalamic defect (tertiary hypothyroidism), or 3) to the secretion of biologically inactive TSH.