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Biomedical subjects

F Silvestrini

Publications and source records attributed to F Silvestrini.

9 recordsLinked to original sources
PubMed1978

Effect of ergot alkaloids on growth hormone and prolactin secretion in humans.

The effects of ergot alkaloids (mainly bromocriptine) on the secretion of GH and PRL in normal subjects and in pathological conditions (i.e. acromegaly and hyperprolactinemic states) are discussed. In the normal subjects, bromocriptine releases GH whereas in about 50% of acromegalics it causes a marked and long-lasting inhibition of the hormone secretion. PRL release is reduced by the drug both in normal subjects and in hyperprolactinemic states. Physiopathological studies in the humans indicate that, according to the experimental data, bromocriptine inhibits GH release in acromegaly and PRL secretion through a dopaminergic mechanism of action playing at the pituitary level. Data are reported on the effectiveness of bromocriptine in the medical treatment of acromegaly and of hyperprolactinemic states.

Acromegaly↗
PubMed1977

Long-term treatment with 2-Br-alpha-ergocryptine in acromegaly.

Thirty acromegalic subjects underwent chronic CB154 therapy (10-20 mg daily) for periods ranging from 3 months up to 2 years. In 18 out of 21 patients, who exhibited consistent HGH reduction following acute administration of the drug, there was also during chronic treatment, a suppression of the plasma HGH levels exceeding 50% of base line values, e.g. from mean daily values between 14-197 ng/ml (mean +/- SEM = 57.8 +/- 12.4 ng/ml pre-treatment) to 2-19 ng/ml (mean 8.3 +/- 1.2 ng/ml post-treatment). In 12 of the subjects who responsed to chronic CB154 treatment, the mean daily values of HGH were below 10 ng/ml. The suppression of plasma HGH was maintained unaltered throughout the whole course of therapy. In the 9 subjects, in whom no consistent HGH decrease was evidenced with acute CB154 administration, there was accordingly a minor or no suppression of HGH values during the chronic treatment. In 13 subjects, irrespective of the degree of their GH responses, the plasma prolactin levels were constantly inhibited by CB154; instead the drug failed to modify significantly the TRH or insulin-induced GH release. These changes in the hormonal parameters were paralleled by marked clinical amelioration and improvement of some of the metabolic alterations frequently encountered in acromegaly, e.g. reduced carbohydrate tolerance, increased insulin resistance, diminished fall of plasma phosphorus after insulin, decreased urinary excretion of phosphate, hyper-hydroxyprolinuria and hyper-calciuria. Collectively, these data demonstrate that CB154 thrapy is effective in reducing HGH hyper-secretion in many acromegalic patients during long-term treatment.

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↗
PubMed1975

Stable reduction of plasma growth hormone (hGH) levels during chronic administration of 2-Br-alpha-ergocryptine (CB-154) in acromegalic patients.

In 7 acromegalic patients in whom plasma hGH concentrations had dropped acutely after a single dose of 2-B r-alpha-ergocryptine (CB-154, 2.5 mg orally) chronic CB-154 treatment (10 mg orally for 30 days) was also accompanied by a significant and stable reduction of hGH. Withdrawal of the drug was followed by a rapid return of hGH to pretreatment values. Reinstatement of oral CB-154 treatment resulted again in suppression of hGH levels measured 30 and 60 days later. In 5 patients, unresponsive to acute administration of CB-154, no appreciable variation in hGH levels was present after 30 days of treatment. These results suggest that 2-Br-alpha-ergocryptine offers a new approach to the medical treatment of acromegaly.

Acromegaly↗