Search PubMed⌕ Search

Biomedical subjects

G Verde

Publications and source records attributed to G Verde.

47 records · Page 3Linked to original sources
PubMed1978

Lisuride hydrogen maleate: evidence for a long lasting dopaminergic activity in humans.

In 12 acromegalics a single oral dose of 0.2 mg lisuride, an ergoline derivative, significantly reduced plasma PRL but not GH concentrations. Three-tenths milligram of the drug significantly reduced plasma levels of the two hormones. Four-tenths milligram of lisuride did not augment this inhibitory effect. Plasma PRL levels were suppressed in all patients, whereas GH levels were reduced by more than 50% of the base-line values in only seven patients who also responded to the administration of 2.5 mg bromocriptine (CB154). In the patients unresponsive to lisuride, CB154 also failed to change GH levels. The suppressive effect of lisuride started at 60 min (at 150 min for CB154) and plasma GH and PRL levels were still markedly suppressed at 300 min. Plasma GH and PRL concentrations were consistently reduced in two acromegalic patients during 2 weeks of chronic treatment with 0.3 mg lisuride four times a day. In six normal subjects, TRH-induced PRL release was significantly inhibited by pretreatment with 0.3 mg of the drug. The similarity in the effects of lisuride and CB154 suggests that the observed effects of lisuride on GH and PRL are attributable to the known dopaminergic activity of the drug. This conclusion is supported by the data showing that pimozide effectively counteracted the inhibitory action of lisuride on GH and PRL release. We suggest that lisuride may be of value in the medical treatment of acromegaly and hyperprolactinemic states.

Acromegaly↗
PubMed1977

Evidence for a dopaminergic activity of methysergide in humans.

The acute administration of 2 mg of methysergide significantly reduced plasma prolactin levels in nine normal subjects and in seven hyperprolactinaemic patients. The prolactin lowering effect of this drug was abolished by sulpiride. Morever methysergide lowered plasma GH levels in four out of nine acromegalic patients, who were also responsive to a dopaminergic drug such as bromocriptine. Although methysergide did not significantly blunt the TRH-induced prolactin release, our data suggest that this drug may affect GH and prolactin release through a dopaminergic mechanism of action. This effect should be taken into account when methysergide is employed as antiserotoninergic drug in neuroendocrinological studies.

Acromegaly↗
PubMed1976

Effect of dopamine infusion on plasma levels of growth hormone in normal subjects and in agromegalic patients.

In ten normal subjects and in twenty acromegalic patients plasma levels of growth hormone were studied after administration of L-dopa and a dopamine infusion. In the ten normal subjects L-dopa, but not dopamine, increased plasma levels of GH. In the acromegalic patients both L-dopa and dopamine were followed by an inhibition of GH release. Since dopamine does not cross the blood-brain barrier, these results, although not excluding a site of action at median eminence level, support the thesis that the inhibitory effect of dopaminergic stimulation on GH release in acromegaly possibly involves receptors present on GH-secreting cells.

Acromegaly↗
PubMed1976

Inhibitory effect of an ergoline derivative, methergoline, on growth hormone and prolactin levels in acromegalic patients.

Plasma levels of growth hormone (GH) and prolactin (PRL) were measured in twelve acromegalic patients after acute administration of an ergoline derivative (methergoline) which has been proposed as a specific serotoninergic blocking agent. The administration of methergoline (4 mg p.o.) was followed by a significant decrease in plasma GH and PRL concentrations. The administration to the same subjects of CB 154 (2.5 mg p.o.), a known stimulator of dopaminergic receptors, led to results almost superimposable to those obtained with methergoline although the suppressive effect of CB 154 on GH and PRL levels was more sustained. Also on the ground of results obtained in these patients with the use of cyproheptadine, phentolamine, or pimozide, we have concluded that methergoline inhibition of GH and PRL release is, in acromegalic patients, most probably due to a dopaminergic mechanism of action.

Acromegaly↗
PubMedDate not supplied

Effectiveness of the dopamine agonist lisuride in the treatment of acromegaly and pathological hyperprolactinemic states.

We have studied the effects of the chronic administration of the dopamine agonist lisuride (L) in 21 acromegalics (group 1) and in 25 patients with pathological hyperprolactinemia (group 2). Before starting the treatment levels of PRL and/or GH were determined during acute tests with L (0.3 mg po) or TRH (0.2 mg iv). L was given in doses ranging between 0.4 and 2.4 mg/day. GH and/or PRL were determined at monthly intervals, TRH (6 patients of group 1 and 10 of group 2) was repeated during L therapy. In 10 patients of group 1 GH levels were reduced below 10 ng/ml by L therapy; in the remaining patients GH levels were reduced by 50% of the pretreatment values or they were unchanged. The correlation (p less than 0.01) found between GH levels during acute and chronic L administration indicates that GH changes after acute test are predictive of the outcome of the treatment. In all patients PRL was reduced during the therapy to at least 50% of the basal values and in most patients PRL fell to the normal range. No correlation was found between PRL levels during acute and chronic L administration. During the therapy TRH still increased GH levels in most patients whereas it failed to raise PRL. The withdrawal of L was followed by a rapid return of GH to the pretreatment values whereas PRL showed a slower increase. In acromegalics whose GH was lowered by L there was also a marked amelioration of clinical and metabolic parameters. The lowering of PRL was accompanied by the resumption of ovulatory menses even in patients with tumoral hyperprolactinemia. Males reported improvement in sexual performance. An improvement of visual field occurred in 1 patient. In 1 patient with a large prolactinoma serial computerized tomography scans performed during 2 yr of treatment showed a marked reduction of the tumor size.

Acromegaly↗