24-hour thyroid-stimulating hormone secretory pattern in elderly men

A chronobiological study was carried out in 10 elderly male subjects (78-83 years) to evaluate the 24-hour thyroid-stimulating hormone (TSH) secretory pattern. 10 young adult males (26-35 years) made up the control group. Hourly blood samples were drawn from each subject for a 24-hour period. TSH levels in elderly subjects showed blunted circadian fluctuations compared to those seen in young adult subjects. Mean 24-hour TSH values in elderly (3.1 +/- 0.3 microU/ml) and young adult subjects (3.5 +/- 0.1 microU/ml) did not differ statistically, but nighttime TSH values observed in elderly subjects (3.2 +/- 0.3 microU/ml) were lower (p less than 0.05) than those recorded in young adults (4.1 +/- 0.1 microU/ml).

Evaluation of anterior pituitary function in adult patients with craniopharyngiomas

Serum LH, FSH, TSH, PRL, GH and cortisol levels were measured in 10 patients with a craniopharyngioma both before and after a combined insulin-induced hypoglycaemia, GnRH and TRH test. In pre-operative studies, only two patients did not show hormonal abnormalities, while eight patients had deficiencies of one or more hormones. The most frequent abnormality was GH deficiency (six cases), followed by gonadotropin (four cases), cortisol (four cases), and TSH (one case), whereas four patients showed high serum PRL values. In post-surgical studies, a significant improvement of pituitary function was observed in two cases, whereas an impairment of previously normal corticotropin reserve was recorded in another case. The data obtained suggest that endocrine abnormalities in patients with craniopharyngiomas are irreversible in most cases.

Pituitary secretion after administration of a new cerebroactive drug, fipexide

The effect of a single oral dose of 400 mg fipexide on pituitary secretion was investigated in 10 elderly non-endocrine patients. Fipexide induced significant decrease (P less than 0.05) in serum prolactin (PRL) values at 90 and 120 min after drug administration, without affecting serum growth hormone (GH), gonadotropin (LH and FSH), thyrotropin (TSH) and cortisol values. Fipexide was unable to modify metoclopramide-induced PRL release in five of these patients. Our results show that this drug acts as a mild dopamine (DA) agonist, probably not directly affecting hypothalamic and/or pituitary DA receptors but indirectly via a reduced DA re-uptake at the pre-synaptic level.

Diurnal prolactin changes in human cerebrospinal fluid

Eight adult male patients suffering from hydrocephalus of differing aetiologies were investigated in order to detect the existence of diurnal variations of prolactin (PRL) concentration in human cerebrospinal fluid (CSF). Blood and ventricular CSF samples were taken every 2 h during the day (0800-2200 h) and every hour during the night (2300-0700 h). CSF mean PRL levels showed significant nyctohemeral variations with low levels (2.1 +/- 0.3 ng/ml) during day-time and higher levels at night (3.3 +/- 0.1 ng/ml), similar to that observed in serum (PRL values: 16.4 +/- 5.2 and 24.8 +/- 4.3 ng/ml during day and night periods respectively). The presence of a 24 h CSF PRL secretory profile similar to that in serum was shown in six patients with normal 24 h mean PRL values and normal diurnal changes in serum. In two patients with an altered serum 24 h secretory pattern no significant nyctohemeral variations in CSF PRL levels were found. Present data show the existence in man of nyctohemeral variations in CSF PRL content related to the 24 h changes of PRL levels in serum.

Serum concentrations of PRL, GH, LH, FSH, TSH and cortisol after single administration to man of a new synthetic narcotic analgesic butorphanol

The i.m. administration to 6 healthy adult male volunteers of 2 mg butorphanol, a potent synthetic opiate analgesic, resulted in a significant rise in serum PRL level, without affecting GH, LH, FSH, TSH or cortisol secretion. These effects indicate that in man butorphanol exerts an opiate agonist rather than an opiate antagonist effect at the hypothalamic and/or pituitary level.

Changes in pituitary secretion induced by an agonist-antagonist opioid drug, buprenorphine

The im administration in 6 healthy subjects of buprenorphine, a derivative of the morphine alkaloid thebaine with agonist-antagonist properties, resulted in a significant rise of serum Prl within 45-240 min, a small and transient increase in serum GH and a significant fall in serum cortisol values. Conversely, no appreciable changes in the serum levels of the other hormones studied were found. The observed hormonal effects indicate that, in man, buprenorphine exerts an opiate agonist rather than an opiate antagonist effect.

Changes of CSF prolactin induced by metoclopramide in man

A sharp increase in serum and CSF prolactin (PRL) values after acute metoclopramide (10 mg i.m.) administration was found in six male patients without endocrine diseases. Peak values occurred simultaneously in serum and in CSF. This finding suggests the possibility that CSF PRL content depends also on the retrograde transport from pituitary gland.

Nyctohemeral pattern of serum LH, FSH and PRL in patients with myotonic dystrophy

The nyctohemeral pattern of serum luteinizing (LH), follicle-stimulating hormone (FSH) and prolactin (PRL) in eight patients with myotonic dystrophy (MD) was studied. Gonadotropin patterns were classified as adult, pubertal or infantile. Six patients showed an adult pattern, whereas two had a pubertal or infantile pattern. A normal pattern of PRL secretion was found in seven patients and a blunted sleep-related hormonal increase was observed in one. Impaired hypothalamic control of pituitary secretion in MD is proposed as the cause for these findings.

Changes of pituitary secretion after long-term treatment with hydergine, in elderly patients

The aim of this study was to evaluate the effects of long-term treatment with an ergot derivative, dihydroergotoxine mesylate (hydergine) 6 mg/day, on pituitary secretion on 10 elderly patients of both sexes. Samples were drawn at 120 min intervals during a 24 h period, before and after 1 month of therapy. Serum levels of Prl, GH, LH, FSH, TSH and cortisol were measured by RIAs. Hydergine induced a significant increase in the nocturnal serum GH peak. Conversely, no appreciable changes in the pattern of the other hormones studied were found. The observed endocrine effects could be due to the chronic dopaminergic stimulation induced by hydergine.

Changes in pituitary secretion after administration of branched-chain amino acids to patients with hepatic cirrhosis

Infusion of a mixture of branched-chain 1-amino acids (BCAA; isoleucine, leucine, and valine) in six male patients suffering from hepatic cirrhosis led to an increase in serum GH, while serum PRL was not affected. In the same patients arginine infusion stimulated GH and PRL release. These findings demonstrate that hypothalamo-pituitary responsiveness to amino acid stimulation is preserved in cirrhosis and that administration of these amino acids has some endocrine effect.

Evaluation of Prl secretion in elderly subjects

Prl secretion was evaluated in 76 elderly patients (71-86z years) without endocrine disorders (38 men and 38 women) in basal conditions, after TRH, sulpiride and levodopa administration and during a 24 h period. An impaired Prl response to the administered drugs was found in the elderly women but not in the men. On the contrary, normal sleep-related serum Prl changes were found in the majority of the subjects studied. These results suggest that the pituitary gland can maintain a good Prl secretory pattern in the elderly.

Pituitary hormone concentrations in cerebrospinal fluid in patients with prolactin and growth hormone-secreting tumors

GH, PRL, LH, FSH and TSH were measured in serum and in cerebrospinal fluid (CSF) in 16 patients with chromophobe adenomas, in 8 with acromegaly and in 18 subjects with neurological diseases without endocrine troubles. Elevated mean GH and PRL levels in serum and in CSF were found in patients with chromophobe adenomas and with acromegaly. No constant correlation was observed between serum and CSF values. The highest hormonal levels in CSF were usually observed in adenomas with suprasellar extension, but this finding was inconstant. The determination of hormonal levels in CSF does not seem to supply any reliable information about the characteristics of pituitary tumors.

Influence of low doses of naloxone on pituitary secretion in man

Naloxone 0.8 mg im administered to eight healthy subjects did not affect the serum levels of GH, LH, FSH, PRL, TSH and cortisol. Pretreatment with naloxone 0.8 mg increased TRH-induced TSH and PRL release in six healthy subjects. The same pretreatment caused an enhancement of haloperidol-induced PRL secretion in further other group of six subjects.

Hormonal changes induced by a partial opiate antagonist, nalorphine. Evaluation of PRL, GH, TSH, LH, FSH and cortisol secretion

The effects of nalorphine 5 mg i. m., a partial opiate antagonist, on circulating levels of PRL, GH, TSH, LH, FSH and cortisol were studied in six healthy men. Nalorphine produced a produced a prompt and sharp increase in serum PRL and a small, delayed rise in serum GH. Serum LH and cortisol decreased after drug administration and no change in serum FSH and TSH was observed. These findings are discussed and a possible site of action of nalorphine is suggested.

Effect of a psychoactive drug, trazodone, on prolactin secretion in man

Administration of 50 mg trazodone, an antidepressant drug, in a single oral dose to 10 normal subjects of both sexes, aged 24--41, resulted in a significant (p less than 0.01) decrease of serum prolactin (PRL) values. The mean serum PRL levels were 8.9 +/- 2.2 ng/ml in basal conditions and 4.5 +/- 1.7 ng/ml 180 min after trazodone. Pretreatment with trazodone does not modify TRH-induced PRL release.

Dopamine receptor blockade induced by metoclopramide and thyroid-stimulating hormone secretion in man

20 mg metoclopramide, intramuscularly administered to 10 healthy males and 10 healthy females, induced a significant increase in serum thyroid-stimulating hormone values in female subjects only. This finding suggests that dopamine does not play a major role in the regulation of thyroid-stimulating hormone secretion and that estrogens can act in the modulation of dopamine effects at the hypothalamic and/or pituitary level.

Prolactin secretion in benign prostatic hypertrophy

Prolactin secretion was evaluated in 22 patients with benign prostatic hypertrophy, before and after thyrotropin-releasing hormone stimulation. Increased prolactin reserve was found. In 11 patients, in whom the test was performed twice, the prolactin response after surgery was higher than in the pre-surgical test. The possible role of prolactin in the genesis of benign prostatic hypertrophy is discussed.

Evaluation of anterior pituitary function in patients with posttraumatic diabetes insipidus

Serum LH, FSH, TSH, PRL, GH, and cortisol were measured in 10 patients with posttraumatic diabetes insipidus both basally and after a combined insulin-induced hypoglycemia, LRH and TRH test. Two patients did not show hormonal abnormalities, while 8 patients had deficiencies of 1 or more hormones. The most frequent abnormality was GH deficiency (50%), followed by TSH (40%), ACTH (30%), FSH (30%0, and LH (20%). These results indicate that anterior pituitary dysfunction frequently accompanies posttraumatic diabetes insipidus.

Evaluation of twenty-four-hour secretory patterns of growth hormone and insulin in patients with myotonic dystrophy

Twenty-four-hour secretory patterns of GH and insulin were evaluated in seven patients with myotonic dystrophy. We found an impairment of sleep-related GH secretion and an increase of nocturnal serum insulin levels. There was no correlation between hormonal behavior and severity of disease. It is possible that the observed hormonal dysfunction is related to a multisystem disorder in myotonic dystrophy.

Evaluation of LH, FSH, TSH, Prl, and GH secretion in patients suffering from prostatic neoplasms

The concentration of luteinizing hormone (LH), of follicle stimulating hormone (FSH), of thyroid stimulating hormone (TSH), of prolactin (Prl) and of growth hormone (GH) was evaluated, in basal conditions and during stimulation tests, in serum of 32 patients with benign prostatic hypertrophy (BPH), of 29 patients suffering from prostatic carcinoma and of a control group of similar age. Significant difference in pituitary Prl secretion was found between the prostatic patients and the control group.

[Hypothalamic neural hormones and evaluation of hypophyseal function]

The authors describe the principal tests employed in clinical evaluation of anterior pituitary function.

Increased serum prolactin pituitary reserve in patients with prostatic neoplasms

Prolactin (PRL) pituitary reserve was measured in 8 patients with prostatic adenoma and 11 patients with prostatic carcinoma. The PRL reserve was significantly higher in these patients compared to an age-matched control group of 6 subjects. A possible role for PRL-inhibiting drugs in the management of oestrogen-resistant carcinomas of the prostate is suggested.

[Effects of somatostatin upon prolactin secretion both in normal subjects and in patients presenting pituitary adenoma (author's transl)]

In normal subjects somatostatin cannot modify the plasma levels of prolactin when they are in a normal range or when they are pharmacologically increased. In the case of pituitary adenoma (prolactinic or eosinophilic), the response of prolactin to somatostatin varies widely. In some patients there is a marked decrease of the prolactin levels while in others no modification is observed.

Inhibition of cimetidine-induced hyperprolactinaemia by pretreatment with levodopa or bromocriptine

A single i.v. administration of cimetidine, an histamine receptor antagonist, produced a significant increase in serum prolactin (PRL) levels in fifteen normal men. This effect was suppressed by pretreatment with levodopa or bromocriptine.

Effects of two analgesic opiates (methadone and pentazocine) on the serum prolactin levels in breast cancer

In 18 female patients affected by advanced breast cancer, the serum prolactin (PRL) levels have been determined under basal conditions and after the administration of analgesic opiates such as methadone and pentazocine. A significant increase of prolactin serum values was found after the use of both drugs. This finding is considered to be of clinical importance.

Changes in pituitary hormones serum levels in bromocryptine-treated parkinsonian patients

In the course of a clinical trial with 2alpha-bromoergocryptin in Parkinson's disease, the serum levels of several pituitary hormones have been studied in the assumption that the drug active on nigro-striatal dopaminergic system might also interfere with hypothalamus-protuberantial neurotransmission, and have effects on the function of the pituitary. No changes in serum levels of FSH, LH, STH and TSH were detected for every dose of the drug employed. Only prolactin serum levels diminished since the beginning of the treatment, the decrease being significant (p less than 0.05 and p less than 0.01). This effect on prolactin does not change in the dose range considered. Clinical improvement was observed for doses of drugs above 15 mg/day, whereas the effect on prolactin secretion occurred with the dose of 7.5 mg/day.

The 24-h pattern of human prolactin in serum

Radioimmunoassay determinations of serum prolactin every 2 hrs in twelve healthy subjects (six women and six men), aged between 22 and 34, reveal that several episodes of hormone secretion occur over a 24-h period. The two episodes displaying significant oscillations have 24-h and 8-h periods, with maxima occurring respectively at 04(30) and at 07(00), 15(00) and 23(00). Accordingly, the highest prolactin levels in serum occur during the night, but oscillations are present throughout the day. The observation schedule adopted leads us to conclude that the main secretory rhythm is synchronized with sleep. The 8-h periods seem to be rather dependent on the course of time.