Effects of tartrate thyrotropin-releasing hormone treatment on serum thyrotropin, free triiodothyronine, free thyroxine and prolactin levels in patients with spinocerebellar degeneration

The aim of the present study was to investigate the pituitary-thyroid axis function during the long-term (30 days) intramuscular administration of 4 mg/day of thyrotropin-releasing hormone tartrate (TRH-T) in 15 patients with spinocerebellar degeneration. The study was performed as follows: (1) acute 4 mg TRH-T test with hourly prolactin (PRL) and thyroid-stimulating hormone (TSH) level evaluations for 6 h; (2) placebo; and (3) 4 mg/day of TRH-T administration for 30 days with TSH, PRL, and free T3 and T4 (FT3 and FT4) levels evaluated on days 1, 15 and 30. Hormone determination was performed just before and 1 h after placebo or TRH-T administration. The acute administration of TRH-T caused a sustained rise of TSH which lasted until the 6th hour and of PRL which declined after 1 h (p < 0.01). During placebo administration, no change of TSH, PRL, FT3 or FT4 was observed. On the 1st day of treatment, 1 h after the TRH-T injection, a significant increase of both TSH and PRL levels occurred (p < 0.01). As compared to the 1st day, a significant decrease of the TSH (p < 0.01) levels occurred on the 15th and 30th days before TRH-T: the TSH response to TRH-T administration was present although less than on the 1st day (p < 0.01). Moreover, throughout the whole period of treatment, no difference was recorded for PRL levels before or after TRH-T administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Bilateral and simultaneous inferior petrosal sinus sampling in the early diagnosis of an ACTH-producing pituitary microadenoma and its detection by magnetic resonance one year later

This study describes a case of pituitary-dependent Cushing's syndrome where standard biochemical and radiological techniques were discordant in localizing the origin of the autonomous adrenocorticotropic hormone (ACTH) hypersecretion in the pituitary. Hormonal evaluation suggested a pituitary genesis for the disease, but both sellar computed tomography and cranial magnetic resonance (MR) were unable to give clear-cut evidence for a pituitary neoplasm. Simultaneous and bilateral inferior petrosal sinus sampling (SBIPS) correctly identified the left side of the pituitary gland as the source of autonomous ACTH production. One year later, the shaded signs of a pituitary lesion in the left side of the gland were seen with MR imaging, and a 0.5-cm in height adenoma was surgically removed. At the 2-year follow-up the patient's symptoms had completely disappeared, and her menses were restored. In this case, SBIPS correctly diagnosed the presence of an ACTH-secreting pituitary microadenoma one year before shaded signs of the pituitary lesion appeared with MR imaging. This is a clear-cut demonstration of the accuracy of the SBIPS technique in localizing small pituitary lesions.

Evaluation of GH paradoxical responses to TRH and LHRH in acromegalic patients during long-term treatment with octreotide

In some acromegalics, GH release can be induced by TRH and/or LHRH administration. The pathogenesis of these GH paradoxical responses was supposed to be a somatotroph-reduced sensitivity to somatostatin, somatotrophin release-inhibiting factor (SRIF), or an hypothalamic derangement of the SRIF release. In this study, this hypothesis was investigated by means of GH suppression during chronic therapy with octreotide [Somatostatin analogue (SMS)] in order to evaluate the possible correlation between GH and insulin-like growth factor 1 (IGF-1) normalization and the disappearance of these paradoxical responses in 15 acromegalic patients: 15/15 with a paradoxical GH rise after TRH and 7/15 with a paradoxical GH rise after LHRH. SMS therapy was administered subcutaneously at the dose of 150-450 micrograms/day. During the treatment, GH and IGF-1 levels normalized in 12 patients and were reduced in the remaining 3 others. The GH response to TRH disappeared in 7 patients, while the GH response to LHRH disappeared in 4 patients. chi 2 analysis failed to show any significant correlation between GH and IGF-1 normalization and the disappearance of GH response to TRH and LHRH (chi 2 = 0.00686). No linear correlation existed between GH/IGF-1 decrease and GH peak or area under the curve at any time ('r' values: TRH test, GH -0.47, IGF-1 -0.48; LHRH test, GH -0.50, IGF-1 -0.49). The absence of any significant correlation between GH/IGF-1 normalization and the disappearance of GH paradoxical responses during chronic octreotide administration suggests that other factors apart from SRIF sensitivity are involved in the genesis of these responses.

Oral and injectable long-lasting bromocriptine preparations in hyperprolactinemia: comparison of their prolactin lowering activity, tolerability and safety

Bromocriptine, a D2 receptor agonist, has been widely used in tumoral and non-tumoral hyperprolactinemia, in reducing both plasma prolactin levels and in restoring fertility and/or menses in most patients. In this study a comparison between the injectable repeatable and the oral slow release formulations of bromocriptine (Parlodel LAR and Parlodel SRO) is reported, with respect to their effectiveness, tolerability and safety. Eleven patients with hyperprolactinemia, submitted to both treatments, were studied for a period of 1-24 months. Among the four patients with macroprolactinoma, three reached normoprolactinemia without complaining of side-effects, with both formulations, while the remaining patient became intolerant of the oral form after 1 year, and is presently being treated with the injectable formulation without presenting any side-effects. Among the five patients with microprolactinoma, two patients had a good response to both drugs; two patients did not reach normoprolactinemia with the injectable formulations, but a progressive decrease of prolactin levels was obtained with Parlodel SRO therapy, and the remaining patient was completely intolerant of the oral form without complaining of side-effects with Parlodel LAR. Two patients had non-tumoral hyperprolactinemia: one was intolerant of both drugs and one tolerated both formulations very well. In conclusion, Parlodel LAR and Parlodel SRO are very effective compounds in the medical treatment of hyperprolactinemic syndromes. The availability of these differing formulations improves the medical therapy, allowing a better choice of therapeutic regimen according to the effectiveness of, and tolerability to, the different drug formulations. In this way also, with poorly tolerant patients, it is possible to choose the better tolerated and more effective formulation of the drug.

Comparison of anterior pituitary hormone levels in the inferior petrosal sinuses and peripheral blood in various pituitary disorders during perihypophysial phlebography

The present study aimed at evaluating the anterior pituitary hormone levels in the inferior petrosal sinuses and in the peripheral blood of 55 patients affected by various pituitary disorders and undergoing perihypophysial phlebography on neurosurgical indication or for diagnostic purposes. The results indicated that in 6 patients with Cushing's disease and in 4 with hyperprolactinemia the secreting adenoma could be localized by inferior petrosal sinus sampling. Furthermore, the concentrations of all the pituitary hormones were found to be higher in the right and/or in the left inferior petrosal sinus than in peripheral blood, showing a clear gradient between central and peripheral samples. Moreover, the evaluation of hormone central/peripheral concentration ratios revealed noteworthy differences, namely, that central/peripheral concentration ratios of GH, ACTH, and PRL were significantly higher than those of TSH, FSH, and LH (p less than 0.01). On the contrary, no significant differences were found when the concentration ratios of GH, ACTH and PRL or TSH, FSH and LH were compared among themselves. This finding may be attributed to at least two factors: the increased pulsatility and the relatively short biological halftime of polypeptic hormones (GH, ACTH, and PRL) compared with glycoprotein hormones (TSH, FSH, and LH).

Rapid and long-lasting suppression of prolactin secretion and shrinkage of prolactinomas after injection of long-acting repeatable form of bromocriptine (Parlodel LAR)

Five patients with PRL-secreting macroadenoma and nine patients with PRL-secreting microadenoma or idiopathic hyperprolactinaemia were treated with monthly administrations of long-acting bromocriptine suitable for repeatable injections (Parlodel LAR) for 1-12 cycles of treatment. A significant shrinkage of tumour mass and the recovery of visual field defects were observed in patients with macroprolactinoma. Plasma PRL levels decreased to 16.8 and 18.1% of pretreatment values, in macroprolactinoma and idiopathic or microadenomatous hyperprolactinaemic subjects, respectively, during the first cycle of treatment, reaching the normal range in three patients of each group. During the following cycles of treatment, two patients with macroprolactinoma and one patient with idiopathic or microadenomatous hyperprolactinaemia became normoprolactinaemic. Adverse reactions generally did not last beyond the first days of administration and decreased with the progression of the treatment. In conclusion, its effectiveness and the fact that it is well tolerated, may suggest that this form of bromocriptine may be used as a first therapeutic approach for patients with PRL-secreting adenomas, particularly when shrinkage of a macroadenoma is urgently required.

Beta-endorphin concentrations both in plasma and in cerebrospinal fluid in response to acute painful stimuli

The beta-endorphin-like-immunoreactivity (beta-ELI) has been evaluated both in plasma and in cerebrospinal fluid (CSF) in 30 patients during trans-sphenoidal surgery. Blood and liquoral samples were collected in five conditions: (1) "reference", (2) "pain", (3) "analgesia", (4) "end", and (5) "24th hour". A significant rise of both plasma and liquoral beta-ELI levels (p less than 0.00001 and p less than 0.08, respectively) when compared to basal ones occurred following the painful stimulation due to the divarication of the nasal mucosa by speculum. A significant decrease (p less than 0.01) was noticed for plasma concentrations at the third sample followed by a new significant increase at the end of the operation, (p less than 0.05 when compared to the third sample and p less than 0.01 when compared to the reference sample). In CSF, beta-ELI levels decreased at the third sample (p less than 0.01 when compared to the painful levels) and at the end of surgery (p less than 0.01, p less than 0.01 and p less than 0.05 vs first, second and third samples, respectively). Twenty-four hours after surgery either plasma and liquoral beta-ELI levels decreased (p less than 0.05). The modifications of the opiatergic system after acute painful stimuli should be, hence, characterized by an early rise followed by a progressive decrease of beta-ELI concentrations. The increase of plasma beta-ELI levels, at the end of surgery, could be due to pituitary manipulation with massive release in the peripheral blood.

Plasma prolactin levels in the inferior petrosal sinuses in various pituitary disorders during perihypophyseal phlebography

The use of intercavernous sinus phlebography for the diagnosis and neurosurgical treatment of pituitary adenomas has enabled the collection of selective venous samplings of the inferior petrosal sinuses (IPSs), where prolactin (PRL) levels can be measured before the hormone becomes excessively diluted in the systemic circulation. In the present study, plasma PRL levels were studied in the right and/or left IPS and, simultaneously, in the peripheral circulation of: (1) normoprolactinemic patients affected with various pituitary disorders which required phlebographic procedures; (2) hyperprolactinemic patients with negative radiological and computed tomographic (CT) signs of pituitary adenomas and (3) adenomatous hyperprolactinemic patients. In the 17 normoprolactinemic patients, the plasma PRL concentration in the IPSs was significantly higher (3.5 times; p less than 0.01) than in the peripheral circulation. In the 11 hyperprolactinemic patients with negative radiological and CT signs of pituitary adenomas, the central gradient for PRL was significantly higher (2.8 times; p less than 0.05) than in the peripheral circulation. No significant difference was detected between PRL concentrations in the left and right IPSs. In the 11 adenomatous hyperprolactinemic patients, there was a significant (p less than 0.01) central gradient for PRL 3.8 times higher than in the peripheral circulation on the ipsilateral side of the tumor. Furthermore, the plasma PRL concentration in the ipsilateral IPS was significantly higher (3.4 times; p less than 0.05) than that in the contralateral sinus. In conclusion, the present study shows that a clear-cut concentration gradient exists between plasma PRL levels in the IPSs and in the peripheral circulation of normoprolactinemic and hyperprolactinemic patients with negative radiological and CT signs of pituitary adenomas.(ABSTRACT TRUNCATED AT 250 WORDS)