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Biomedical subjects

G Faglia

Publications and source records attributed to G Faglia.

At least 127 records · Page 7Linked to original sources
PubMed1989

Effects of the opiate agonist loperamide on pituitary-adrenal function in patients with suspected hypercortisolism.

In the present work the possible use of loperamide, an opiate agonist, in the dynamic evaluation of patients with suspected hypercortisolism was investigated. The effects of loperamide on plasma ACTH and cortisol levels were evaluated in normal subjects and in 58 patients with suspected Cushing's syndrome. The results were compared to those obtained after the overnight dexamethasone suppression test. In normal subjects plasma ACTH and cortisol levels were significantly (p less than 0.005) suppressed by both loperamide (16 mg po) and dexamethasone (1 mg po). In 17 patients, in whom the diagnosis of Cushing's syndrome was confirmed by subsequent investigations, neither loperamide or dexamethasone inhibited cortisol (from a baseline of 606 +/- 55 nmol/L) to a nadir of 502 +/- 43 nmol/L and 539 +/- 50 nmol/L, respectively) and ACTH concentration (from a basal level of 70.1 +/- 11.8 pg/ml to a nadir of 46.0 +/- 8.6 pg/ml and 54.3 +/- 7.5 pg/ml, respectively). In 34 patients, in whom the suspect of hypercortisolism was ruled out, either loperamide or dexamethasone suppressed the pituitary-adrenal axis: cortisol and ACTH levels significantly fell from 417 +/- 24 nmol/L and 28.3 +/- 3.5 pg/ml to 60 +/- 6 nmol/L and 14.4 +/- 1.4 pg/ml after loperamide and to 26 +/- 4 nmol and 16.4 +/- 1.7 pg/ml after dexamethasone. In 7 patients discordant responses were observed. In 3 patients treated with antiepileptic drugs ACTH and cortisol levels were inhibited by loperamide, but not by dexamethasone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocortical Hyperfunction↗
PubMed1989

Studies of two thyrotrophin-secreting pituitary adenomas: evidence for dopamine receptor deficiency.

Of 22 previously reported patients with TSH-secreting pituitary adenomas challenged with dopamine agonists, 18 showed no decrease in serum TSH. There have been few in-vitro studies of these rare tumours so the mechanism of the dopaminergic resistance has remained obscure. We describe two further patients with thyrotrophinomas; the first was thyrotoxic (T3 6.1 nmol/l, TSH 7 mU/l) and the second was diagnosed after radioiodine for presumed Graves' disease. The second patient had an alpha-subunit: TSH molar ratio less than unity (0.27). In-vivo TSH responses to TRH, bromocriptine and domperidone were compared with those of the resected tumour cells in vitro, the latter studied using a continuous perifusion system. Dopamine receptors were sought in membranes from each tumour using a radioreceptor assay employing 3H-spiperone. Patient 1 showed significant increases in serum TSH (7 to 13 mU/l) and alpha-subunit (18.7 to 385 ng/ml) after 200 micrograms TRH (i.v.) but patient 2 showed no such increases (TSH: 69 to 72 mU/l, alpha-subunit: 4.9 to 5.2 ng/ml). Neither patient showed a change in serum TSH following bromocriptine 2.5 mg (orally) or domperidone 10 mg (i.v.), though serum PRL responded normally. Serum TSH from patient 1 was of apparently normal molecular size but increased bioactivity (B/I ratio 3.8) and that from patient 2 was of increased molecular size but reduced bioactivity (B/I ratio 0.1). Tumour cells from each patient immunostained for TSH beta and alpha-subunit, and secreted TSH in vitro. The first showed dose-dependent TSH release after TRH (1-100 ng/ml) which could not be inhibited by dopamine (5 mumol/l) but the second was unresponsive to TRH in vitro. Neither tumour showed inhibition of TSH release by dopamine (5 mumol/l) or bromocriptine (0.01-10 nmol/l) and neither contained membrane-bound dopamine receptors. The results suggest that the dopaminergic resistance typical of most TSH-secreting pituitary adenomas may be due to altered or absent membrane-bound dopamine receptors.

Adenoma↗
PubMed1989

Cabergoline: long-acting oral treatment of hyperprolactinemic disorders.

Cabergoline, a new orally active dopaminergic drug with an extremely long-lasting PRL-lowering effect, was given to 48 hyperprolactinemic women for 3-18 months (median, 8 months) at doses varying between 0.2-3 mg/week administered one to three times weekly. Serum PRL levels declined to normal in 41 women, 30 of whom received 0.2-1 mg cabergoline once weekly, 8 received 0.2-0.5 mg twice weekly, and 3 received 0.4-0.6 mg 3 times weekly. Five women had slightly supranormal serum PRL levels while receiving 0.3-0.6 mg once weekly, but the dose was not increased because the lower dose had produced the desired clinical benefit. Two women had 50% reductions in their serum PRL levels, but remained hyperprolactinemic while receiving 2-3 mg cabergoline weekly. Among 30 amenorrheic women, 28 had resumption of menses, the exceptions being 2 hypopituitary women, presumptive evidence of ovulation was available in 21. Marked tumor shrinkage occurred after 3-month treatment in 5 of the 6 women who had macroprolactinomas. Only 4 women had side-effects during the first weeks of treatment, and these vanished despite continued cabergoline administration at the same or reduced, but still effective, doses. In a short term, double blind study, cabergoline at 3 different schedules (0.4 mg twice weekly, 0.2 mg 4 times weekly, and 0.4 mg 3 times weekly for 3 weeks, followed by 0.4 mg twice weekly) or placebo was given to a total of 24 hyperprolactinemic women (6 in each subgroup) for 8 weeks, with weekly evaluation of serum PRL levels and side-effects. All 3 cabergoline schedules, but not placebo, induced significant reductions in serum PRL concentrations during the 8-week treatment period. Mild transient side-effects occurred in 7 drug-treated patients (nausea in 5; dizziness in 3). We conclude that cabergoline is effective treatment for hyperprolactinemia. Its efficacy, tolerability, and long duration of action may make it the drug of choice for patients with hyperprolactinemia.

Administration, Oral↗
PubMed1988

Dissociated thyromimetic effects of 3, 5, 3'-triiodothyroacetic acid (TRIAC) at the pituitary and peripheral tissue levels.

Although TRIAC is bound at least twice as avidly to nuclear receptor as T3, its thyromimetic potency is relatively low and its effect at the pituitary level on thyrotropin (TSH) secretion seems to be dissociated from that at the peripheral tissue level. In order to gain further insight into the complex effects of this thyroid hormone analog, we studied the effects of long-term TRIAC administration (2.8 mg/day for 2 months) on TSH secretion, circulating free thyroid hormone (FT4 and FT3) levels and some parameters able to evaluate the peripheral thyroid hormone action, in 5 mild obese subjects on low caloric diet (1200 kcal/day). The results were compared to those obtained in 5 mild obese subjects matched for age, sex and weight on low caloric diet alone. TRIAC administration completely inhibited the secretion of both basal and TRH-stimulated TSH in few days, and consequently serum FT4 and FT3 concentrations progressively dropped to very low levels, while no significant changes in both TSH and free thyroid hormone levels were recorded in the control group. The body weight significantly fell in both groups, without any difference between TRIAC treated and untreated patients. The heart rate was constant throughout the course of the study in both groups of patients. Serum total cholesterol, triglyceride and total lipid concentrations significantly decreased in both groups, and the decrement recorded in TRIAC treated patients was not significantly different from that found in patients on diet alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Addison's disease and empty sella.

A 47-year-old woman affected by Addison's disease, inadequately treated with corticosteroids for 14 yr, was referred to our clinic. As a x-ray of skull revealed an enlarged sella turcica, a more thorough study of hypothalamic-pituitary function and of the sellar region was performed. The normal suppression of high plasma ACTH levels induced by hydrocortisone infusion and the normal pattern of ACTH, TSH, PRL, LH and FSH to appropriate stimuli (CRH, TRH, GnRH) excluded the possible existence of an ACTH-secreting adenoma; the CT scan images showed the presence of an empty sella. The impaired GH rise after GHRH may be attributed to either the empty sella or the adrenal failure. This is the first patient with Addison's disease and empty sella, in whom the hypothalamic-pituitary function has been studied by the administration of four releasing hormones.

Addison Disease↗
PubMed1988

Different GH responsiveness to repeated GHRH administration in normal children and adults.

It has been previously reported that repeated GHRH administration leads to a reduction in growth hormone responses in adults. In order to verify if this regulatory mechanism is also operating in children, we compared GH secretory responses to repeated GHRH in normal children and adults. The administration of the first GHRH bolus caused a marked GH rise (expressed as net incremental area under the curve, nAUC +/- SE) both in children (GH nAUC: 1184 +/- 216 ng/ml/h) and in adults (GH nAUC: 701.2 +/- 90 ng/ml/h). The second GHRH bolus induced a different pattern of GH secretion in the two groups. In children the peptide determined a clear GH rise (GH nAUC: 518 +/- 147 ng/ml/h), while in adults the second GHRH injection was uneffective (GH nAUC: 21 +/- 20 ng/ml/h). These preliminary results indicate that in children repeated GHRH administration does not induce refractoriness to GHRH action, suggesting different regulatory mechanism of GH secretion in normal children and adults.

Adolescent↗
PubMed1988

Loperamide, an opiate analog, differently modifies the adrenocorticotropin responses to corticotropin-releasing hormone and lysine vasopressin in patients with Addison's disease.

Loperamide is a peripheral opiate agonist able to inhibit ACTH secretion. In this work, the interactions between loperamide and two ACTH secretagogues, lysine vasopressin (LVP) and corticotropin-releasing hormone (CRH), were investigated in patients with Addison's disease. After loperamide (16 mg orally) or placebo administration, 5 patients received LVP (0.06 IU/kg i.v. over 1 h) and 6 patients received oCRH (1 micrograms/kg i.v. as bolus). In all patients loperamide induced a significant fall in plasma ACTH levels. LVP increased ACTH levels after both loperamide (from 48 +/- 17.3 to a peak of 95 +/- 21 pmol/l) and placebo (from 231 +/- 59.5 to 365 +/- 86.6 pmol/l): the interaction between treatments and time was not significant. CRH caused a rise in plasma ACTH after both loperamide (from 30 +/- 16.6 to a peak of 108 +/- 31 pmol/l) and placebo (from 98.5 +/- 47 to 211 +/- 61.7 pmol/l): the interaction between treatments and time was significant, and the first phase of CRH-induced ACTH secretion was significantly lower after loperamide. These data demonstrate that loperamide differently modifies the stimulatory action of LVP and CRH on ACTH secretion: namely, LVP and loperamide act in an additive manner, while CRH and loperamide interact in a non additive way. Although these findings might be explained by the involvement of different intracellular ACTH-secreting mechanisms, an influence of loperamide on some suprapituitary factors modulating the ACTH response is suggested.

Addison Disease↗
PubMed1988

Treatment of inappropriate secretion of thyrotropin with somatostatin analog SMS 201-995.

Inappropriate thyrotropin secretion (IST) may originate from either neoplastic disease (nIST) or non-neoplastic resistance to thyroid hormone (nnIST). An inhibitory effect of somatostatin on TSH secretion has been documented. In an attempt to elucidate the possible therapeutic effect of this peptide on nIST and nnIST, a study was conducted in 7 such patients. Sandostatin (SMS 201-995) was administered in daily doses of 100 micrograms for several days to 1 month. Four patients with nIST responded with a fall in circulating TSH as well as alpha-subunit with concomitant normalization of free thyroxine and clear symptomatic improvement. In the 3 nnIST patients this effect was considerably less apparent and a partial TSH escape was observed on long-term treatment in 2 cases. The importance of somatostatin and its analogs in the management of thyroid malignancy is stressed.

Antineoplastic Agents↗
PubMed1988

Growth hormone and prolactin secretion in acromegaly: correlations between hormonal dynamics and immunocytochemical findings.

A morphological study was carried out on pituitary adenomas removed from 13 normoprolactinemic and 9 hyperprolactinemic acromegalic patients whose hormonal dynamics had been carefully investigated. Double immunocytochemical labeling with the protein-A-gold electron microscopic technique was used to detect the presence of GH and PRL in the adenomas. Two morphological patterns were found; 11 adenomas contained cells positive only for GH, and 11 contained a variable proportion (from 10-98%) of cells positive for PRL. The great majority of cells positive for PRL also were positive for GH and so were actually mammosomatotrophic cells. Among the normoprolactinemic patients, no cells containing PRL were found in the tumors from 8 patients, and 10-26% of the cells of the tumors of the other 5 patients contained PRL. Two thirds of the hyperprolactinemic patients had tumors containing mammosomatotrophs (18-80%) with or without the concomitant presence of mammotrophs (0-18%). A positive correlation was found between the serum PRL levels and the percentage of mammosomatotrophs. No significant differences in GH secretory responses to TRH, dopamine, GHRH, and SRIH were found between patients having tumors with or without cells positive for PRL. We conclude that 1) the frequency of mammosomatotrophs in adenomas from acromegalic patients is higher than that previously estimated using different immunocytochemical methods; and 2) serum GH responses to TRH and dopamine are not strictly related to the presence of mammosomatotrophs and/or mammotrophs within the tumor.

Acromegaly↗
PubMed1987

Vasoactive intestinal polypeptide and dopamine: effect on prolactin secretion in normal women and patients with microprolactinomas.

In order to investigate the influence of dopamine (DA) in modulating prolactin (PRL) response to vasoactive intestinal polypeptide (VIP), VIP (75 micrograms i.v. over 12 min) was administered to normal women and patients with microprolactinomas during saline or DA (0.06 micrograms/kg BW/min) infusion. In 8 normal women VIP caused PRL to rise from 7.9 +/- 0.8 (mean +/- SE) to 33.4 +/- 17.1 ng/ml (p less than 0.01), the peak occurring at 15 min, while it did not elicit any significant modification in serum PRL levels in 18 patients with microprolactinomas. DA infusion lowered serum PRL by 67 and 58.2% at 120 min in normal women and in patients with microprolactinomas, respectively, and abolished VIP-induced PRL response in normal women without influencing PRL response in patients with microprolactinomas. PRL responsiveness to VIP was not restored by dopaminergic disinhibition (domperidone 10 mg i.v.) in 4 patients tested. Two previously unresponsive patients showed a VIP-induced PRL increase, superimposable on that recorded in normal women, after successful selective adenomectomy. These data suggest that DA, although able to suppress VIP-induced PRL response in normals, does not play any major role in causing unresponsiveness to VIP in prolactinomas. The lack of PRL responsiveness to VIP might be intrinsic to the adenoma or due to alterations of PRL secretion regulatory mechanisms other than DA secondary to the presence of the tumor, or to a depletion of the readily releasable pool of PRL.

Adolescent↗
PubMed1987

Inappropriate secretion of thyrotropin by the pituitary.

Inappropriate secretion of thyrotropin (IST) is characterized by elevated serum free thyroid hormone and unsuppressed thyrotropin (TSH) levels, and results from either a TSH-secreting pituitary tumor (nIST) or a selective resistance to thyroid hormone action (nnIST). Although in most patients TSH levels are definitely high, in a quarter of the cases they are within the 'normal range'. In some of these cases, TSH had an elevated biologic activity and an apparent molecular weight smaller than in normals. The current availability of ultrasensitive TSH immunoradiometric assay, able to distinguish suppressed from unsuppressed TSH levels enables the recognition of the disease. The distinction between nnIST and nIST rests on clinical, neuroradiological, and biochemical criteria, the most useful of which are the alpha-subunit:TSH molar ratio (increased in nIST), and the evaluation of the TSH responses to thyrotropin-releasing hormone and high doses of 3,5,3'-triiodothyronine, both qualitatively normal in nnIST, while absent in nIST. The therapy of choice for patients with nIST is pituitary surgery, followed by irradiation in case of surgical failure. Chronic administration of bromocriptine is effective in a minority of cases. The long-acting somatostatin analogue SMS 201-995 has given promising results in 2 patients. In nnIST, bromocriptine is frequently uneffective, while small doses of 3,5,3'-triiodothyronine or 3,5,3'-triiodothyroacetic acid, a thyroid hormone derivative with a strong inhibitory effect on TSH secretion but poor thyromimetic activity on peripheral tissues, are effective in controlling TSH hypersecretion.

Humans↗
PubMed1987

Lack of desensitization of adenomatous somatotrophs to growth-hormone releasing hormone in acromegaly.

The study was undertaken to investigate whether GHRH causes desensitization in GH-secreting adenomas in analogy to the normal situation. For this purpose, GH secretion after repeated GHRH administration to acromegalic patients in vivo and cultured adenomatous somatotrophs in vitro was studied. Six acromegalic patients and 6 normal subjects received 3 consecutive 50 micrograms GHRH rapid iv injections at 2-h intervals. Blood samples were drawn at 0, 15, 30, 60, and 120 min after each dose. The acromegalic patients had variable responses to the first injection and in each patient the second and third injections elicited serum GH responses that were quite similar to those after the first one. The GH increment, evaluated as net incremental area under the curve (mean +/- SE; nanograms per ml/120 min) was 2660 +/- 1501 after the first injection, 2176 +/- 1378 after the second injection, and 1978 +/- 1191 after the third injection; P = NS. On the contrary, in normal subjects a marked elevation of GH was observed only after the first injection (net incremental area under the curve, mean +/- SE after the first injection: 710 +/- 154; after the second injection: 6 +/- 39 and after the third injection: 108 +/- 28, P less than 0.01 vs. the first dose). The effect of in vitro GHRH pretreatment on the subsequent response to GHRH was evaluated in monlayer cultures from 12 GH-secreting adenomas. At 10(-8) M, GHRH significantly stimulated GH release from 8 adenomas. The GHRH pretreatment that was effective in inducing desensitization in cultured rat anterior pituitary cells, i.e. preexposure of the cultured cells to 10(-8) M GHRH for 4 h at 37 C, did not abolish the GH response to the subsequent challenge with GHRH (mean percent stimulation: 150 +/- 14% in untreated cells vs. 153 +/- 30% in pretreated cells; P = NS). Only in one adenoma, did GHRH-promoted desensitization occur. No modification was found in GHRH unresponsive adenomas. In the adenomas, not only the efficacy but also the potency of GHRH on GH release after GHRH pretreatment was of the same order of magnitude as in untreated cells. No desensitization to GHRH action occurred when the pretreatment time was prolonged up to 8 h and the GHRH concentration in the preincubation medium was increased to 10(-7) M.(ABSTRACT TRUNCATED AT 400 WORDS)

Acromegaly↗
PubMed1987

Dihydroergocriptine in management of microprolactinomas.

The effects of dihydroergocriptine (DHECP), a dihydrogenated ergot alkaloid with dopaminergic agonistic and alpha-adrenergic antagonistic properties, were studied in 22 women with PRL-secreting microprolactinomas and compared with those recorded in 36 previously studied patients treated with bromocriptine (BRC). After acute administration of 5 mg DHECP, orally, serum PRL decreased by 61 +/- 18% (+/- SD); only 1 patient was unresponsive. The nadir was reached at 300 min. Long term treatment with increasing DHECP doses caused a progressive PRL fall from 125 +/- 142 (+/- SD) to 81 +/- 159 micrograms/L after 1 week of a 3 mg twice daily regimen, to 64 +/- 88 micrograms/L after 1 week of 5 mg twice daily, 46 +/- 57 micrograms/L after 1 week of 10 mg twice daily, and 28 +/- 34 to 33 +/- 45 micrograms/L throughout 9 months of treatment with 10 mg DHECP 3 times daily. Seventy-seven percent of patients had normal serum PRL levels during chronic treatment. All women, including those with supranormal serum PRL levels, resumed regular menses, and 16 had ovulatory cycles; 1 woman became pregnant. Galactorrhea disappeared in all. During treatment the PRL response to TRH, initially absent in all patients, became positive in 10. In 7 patients, after DHECP treatment for 9 months, high definition computed tomographic scan no longer showed the focal lesions initially seen. After drug withdrawal, serum PRL increased again in all except 1 patient. Two patients had regular menses for 6 months, and 3 still had no adenoma imaged by high definition computed tomography. In BRC-treated patients the serum PRL changes and clinical results were very similar to those in the DHECP-treated patients, except for the persistence of normal serum PRL levels in 4 patients after drug withdrawal. On the other hand, side-effects were negligible during DHECP treatment, but remarkable during BRC. Systolic and diastolic blood pressures decreased by only 5.4 and 3.0 mm Hg, respectively, after acute 5 mg DHECP administration, but decreased by 12.8 and 14 mm Hg after acute 2.5 mg BRC administration. Orthostatic hypotension and peripheral vasomotor phenomena occurred in the long term DHECP treated patients except one, but they occurred in 9 and 3 of those treated with BRC, respectively. Gastric discomfort or mild nausea occurred in 12 DHECP-treated patients, while mild or severe nausea or vomiting were observed in 18, 11, and 2 of those taking BRC, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

Vasoactive intestinal polypeptide enhances ACTH levels in some patients with adrenocorticotropin-secreting pituitary adenomas.

Vasoactive intestinal polypeptide (VIP) was administered (75 micrograms iv over 12 min) to 14 patients with Cushing's disease, 1 patient with Nelson's syndrome, and 8 normal subjects. VIP induced a significant rise of plasma ACTH levels in 6 patients with Cushing's disease, from a baseline of 13.2 pmol/l (9.9-18.5 pmol/l) to a peak of 24.5 pmol/l (7.7-18.9 pmol/l), median and range (P less than 0.05), and in the patient with Nelson's syndrome, from a baseline of 260.9 to 461.3 pmol/l. A significant elevation of cortisol levels was also observed, from a baseline of 567 nmol/l (185-842 nmol/l) to a peak of 727 nmol/l (364-1029 nmol/l); P less than 0.05. No modifications in plasma ACTH and cortisol levels were noticed in the other 8 patients with Cushing's disease, or in the normal subjects. In the responsive patients, the median plasma ACTH level reached after VIP was found to be less than that induced by CRH administration. In 2 of the responsive patients, VIP was injected again after successful microadenomectomy and did not then cause changes in ACTH and cortisol concentration. These data demonstrate that VIP specifically stimulates ACTH release in some patients with corticotropinomas but not in normal subjects; the disappearance of such abnormal ACTH responses after successful adenomectomy suggests the presence of specific VIP receptors only on the adenomatous corticotropes.

Adenoma↗
PubMed1987

Hyperthyroidism due to a thyroid-stimulating hormone (TSH)-secreting pituitary adenoma associated with functional hyperprolactinaemia. A case report.

This paper reports the case of a 31-year-old woman with hyperthyroidism, increased TSH and thyroid hormone levels, evidence of a pituitary adenoma, hyperprolactinaemia, amenorrhoea, and galactorrhoea. Following trans-sphenoidal pituitary adenomectomy, mild hyperthyroidism and increased TSH and alpha subunit levels persisted, whereas hyperprolactinaemia, amenorrhoea, and galactorrhoea disappeared. Serum TSH levels were not affected by administration of TRH, metochlopramide, domperidone, l-dopa or somatostatin. Serum TSH chromatography showed a normal pattern. Following a second trans-sphenoidal pituitary adenomectomy and radiotherapy, hyperthyroidism disappeared, and the TSH and alpha subunit levels returned to normal. Light microscopy showed no specific TSH immunostaining although electron microscopy revealed numerous secretory granules alined along the plasma membrane. The post-operative follow-up confirmed the presence of a TSH-secreting pituitary adenoma associated to functional hyperprolactinaemia.

Adenoma↗