to luteinizing.

The effect of luteinizing hormone-releasing hormone (LHRH) on plasma prolactin (PRL) was studied in eight acromegalic patients. After LHRH injection a significant increase in plasma prolactin levels was obtained in three of them. This non specific prolactin response to LHRH represents an additional proof of the well known abnormalities of pituitary hormone response to various stimuli in acromegaly.

Hyperthyroidism with elevated plasma TSH levels and pituitary tumor: study with somatostatin.

In a 51-year-old man with hyperthyroidism, elevated plasma TSH levels, and evidence of pituitary tumor, plasma TSH levels decreased from a mean basal value of 11 muU/ml to 6 mu/u/ml during the infusion of 200 mug of somatostatin in 60 min. Thyrotropin releasing factor failed to increase plasma TSH levels. T3 administration failed to supress significantly the elevated thyroid 131I uptake. During T3 administration plasma TSH levels showed a downtrend but were not clearly suppressed. These findings are discussed in light of the pertinent literature.

Failure of dopamine infusion to suppress the plasma prolactin response to sulpiride in normal and hyperprolactinemic subjects.

In eleven normal women dopamine infusion (5 microgram/Kg/min) significantly lowered plasma prolactin levels but failed to suppress the PRL response to sulpiride (10 or 100 mg i.v.), while the same dose of dopamine was effective in abolishing the PRL response to TRH (200 microgram i.v.). In four hyperprolactinemic women showing an impaired PRL response to sulpiride, dopamine infusion was effective both in lowering PRL circulating levels and in restoring an evident response to sulpiride. This finding suggests an impairment of endogenous dopamine activity in hyperprolactinemic amenorrhea.

Changes in radioiodine turnover in patients with autonomous thyroid adenoma treated with percutaneous ethanol injection.

UNLABELLED: In 24 patients with autonomous thyroid adenoma, we studied the hormonal pattern (free thyroxine, free triiodothyronine and thyroid stimulating hormone) and markers of radioiodine turnover before and after nodule ablation with percutaneous ethanol injection. METHODS: The hormonal pattern was studied before treatment and at various intervals after nodule ablation. Changes in radioiodine turnover were studied measuring 131I protein-bound iodine and the biologic half-life of radioiodine in the thyroid (calculated from thyroid uptake at 24 and 48 hr) before and after ethanol treatment. RESULTS: The hormonal pattern was normalized by treatment in all patients and remained normal for the follow-up period. Before treatment, protein-bound 131I was elevated in all patients but 4; after treatment, it normalized in 15 patients with the disappearance of the adenoma on scintigraphy. In the remaining 9 patients with only partial nodule destruction on scintigraphy, protein-bound 131I remained elevated although markedly reduced. Biologic half-life was shortened in 18 of 24 patients before treatment; after treatment, it was normal in 18 of 24 patients (13 of 15 with complete nodule ablation and 5 of 9 with partial ablation). CONCLUSION: Ethanol treatment normalized the hormonal pattern in all patients. Measures of radioiodine turnover were better markers of residual disease in that they normalized in almost all patients with complete nodule ablation, whereas they remained abnormal in a high proportion of patients with incomplete ablation. Thyroid hormones remained normal over a follow-up period of 3-7 yr in all patients.

Dosimetry study in patients with autonomous thyroid nodule who are candidates for radioiodine therapy.

UNLABELLED: A dosimetry study was performed on 26 patients with an autonomous thyroid nodule and suppressed serum thyroid-stimulating hormone, to determine the dose to extranodular tissue when the nodule receives 300 Gy for 131I therapy. METHODS: Parameters of radioiodine turnover to be used in the dosimetry formula were separately obtained for the nodule and the contralateral lobe, as a measurable example of the extranodular tissue, using 55 MBq 123I and a computer-assisted gamma camera. The biologic half-life of 123I was then converted into the effective half-life of 131I, and the volumes of the nodule and the lobe were obtained by scintigraphy or sonography. RESULTS: The mean dose to the contralateral lobe from uptake and irradiation by the nodule was calculated to be 32 Gy, and that to the ipsilateral lobe was estimated to be 34 Gy. CONCLUSION: During radioiodine therapy for autonomous thyroid nodules, the extranodular tissue receives a higher dose than is generally assumed, which explains the relatively high rate of post-treatment hypothyroidism reported in the literature.

Plasma pancreatic polypeptide response to secretin.

OBJECTIVE: Intravenously administered secretin stimulates pancreatic polypeptide (PP) release in patients with endocrine enteropancreatic tumors, but data in patients with nontumorous disorders are controversial. Therefore, we aimed to evaluate the plasma PP pattern after secretin administration in healthy subjects and in patients with gastroduodenal diseases investigated for recurrent ulcer disease and/or hypergastrinemia. METHODS: Synthetic secretin was given as an intravenous bolus (2U/kg) in ten patients with Zollinger Ellison syndrome, ten with duodenal ulcer, ten with atropic gastritis and ten healthy volunteers. Blood samples were taken before and at regular intervals for 30min after secretin injection. Plasma PP and gastrin levels were measured by radioimmunoassay. RESULTS: Secretin promptly and significantly (P<0.01) increased PP plasma levels in all groups of subjects without any differences in peak values. There were no significant correlations between PP and gastrin plasma levels. CONCLUSIONS: Secretin at pharmacological doses is a powerful stimulus for PP release.

Inhibitory effect of calcitonin on growth hormone and insulin secretion in man.

The effect of calcitonin administration on basal and arginine-stimulated growth hormone and insulin plasma levels was investigated. The intramuscular injection of synthetic salmon calcitonin (100 U MRC) in five normal subjects produced a significant decrease (p less than 0.05) in insulin concentration. The same amount of calcitonin given 15 min before an arginine infusion test in seven normal subjects significantly reduced the response of growth hormone (p less than 0.025) and insulin (p less than 0.005) to the stimulus.

Dose-response study of the inhibiting effect of somatostatin on growth hormone and insulin secretion in normal subjects and acromegalic patients.

A dose-response study of the effect of somatostatin on plasma growth hormone (GH) and immunoreactive insulin (IRI) levels was performed in normal subjects and acromegalic patients. In normal subjects 150 mug of somatostatin completly suppressed GH and IRI responses to arginine, while with 75 and 37.5 mug only a partial suppression was usually observed. Basal levels of plasma IRI were significantly lowered within 15 min from the start of somatostatin injection at each of the three dose levels. In three acromegalics the doses of 150 and 75 mug of somatostatin were effective in lowering both GH and IRI levels; the dose of 37.5 mug was still effective in lowering plasma IRI levels, while GH levels were not significantly modified. A dose of somatostatin inhibiting GH secretion without affecting insulin secretion has not been found either in acromegalics and in normals. It was concluded that the effects of somatostatin on GH and IRI secretion cannot be easily dissociated.

Inhibitory effect of somatostatin on dibutyryl cyclic AMP-induced insulin and growth hormone release in human subjects.

The effect of somatostatin on the responses of blood glucose, plasma immunoreactive insulin (IRI), growth hormone (GH), and free fatty acids (FFA) to the injection of dibutyryl cyclic AMP (DBC) was studied in six normal volunteers. DBC, when injected alone, induced a rapid increase in blood glucose and plasma IRI levels, while GH concentrations showed a less marked and more delayed increase and plasma FFA showed a clear downtrend. Somatostatin infusion suppressed the GH and IRI release induced by DBC, potentiated its hyperglycemic effect and changed the pattern of FFA. These results suggest that somatostatin inhibits hormone secretion distal to the generation of cyclic AMP.

Plasma ACTH-response to the corticotropin releasing factor in patients with Cushing's disease. Comparison with the lysine-vasopressin test.

In three female patients with Cushing's disease, 100 micrograms of synthetic ovine corticotropin releasing factor (CRF) were administered before surgery and 1 week after transsphenoidal microadenomectomy. In these patients a test with lysine-vasopressin (LVP), 10 U intramuscularly, was also performed before and after pituitary surgery. Before surgery, both stimuli induced a clear increase in plasma ACTH and cortisol in all patients; the response of ACTH to CRF was of greater magnitude. Postoperatively, the responses were virtually absent in two patients, but were still present in the third one in whom the removal of adenoma had been partially unsuccessful. The CRF test was also performed in a female patient with Cushing's syndrome due to adrenal adenoma; in this patient no responses of plasma ACTH and cortisol to CRF were recorded. This paper demonstrates that pituitary microadenomas causing Cushing's disease may retain the ability to respond to CRF; this stimulus may be useful in the differential diagnosis between ACTH-dependent and independent Cushing's syndrome; the lack of response after microadenomectomy indicates successful removal of the tumor. CRF is more potent than LVP in releasing ACTH at the doses employed.

Spontaneous remission of Cushing syndrome after termination of pregnancy.

A 27-year-old women developed Cushing syndrome during pregnancy. The course of pregnancy was characterized by abnormally low urine and plasma estrogen levels despite the presence of a living fetus. The signs and symptoms of Cushing syndrome disappeared spontaneously within 2 months after delivery. Hormonal studies, however, suggested the presence of an adrenal tumor. An adrenocortical adenoma was found at surgery and removed.

Suppression of puerperal lactation by metergoline.

Based on the known stimulatory effect of serotonin on prolactin secretion, a trial of suppression of puerperal lactation by a potent serotonin antagonist, metergoline, was carried out in 30 puerperal women who did not want to nurse. The drug was administered orally at the dose of 4 mg tid for 5 days to all subjects, starting between 24 and 72 hours from delivery. Lactation was either prevented or rapidly suppressed in all subjects. Rebound of lactation after the end of treatment was observed in 10% of cases. Metergoline administration was associated with a significant suppression of the plasma prolactin levels.

Corticotropin releasing factor stimulates cAMP formation in pituitary corticotropic tumor cells.

Addition of corticotropin-releasing factor (CRF) to membranes from two ACTH-secreting pituitary tumors strikingly increased in a dose-dependent fashion adenylate cyclase (AC) activity. Significant stimulation was already apparent at 10(-9)M CRF. Stimulation of AC activity by CRF in membranes from non-tumoral tissue adjacent to tumoral corticotrophs was considerably lower, and was lacking in membranes from a growth hormone secreting tumor. These data correlated well with in vivo pre-surgery and post-surgery ACTH responsiveness to CRF of the tumor bearing patients. Basal AC activity was higher in pituitary adenomas than in non-tumoral adjacent tissue. It is concluded that 1) a CRF-sensitive AC exists in ACTH-secreting tumor cells and, 2) increased sensitivity to CRF, as evidenced by greater stimulation of AC activity, may be responsible for the increased ACTH output of tumoral corticotrophs.

[Percutaneous ethanol injections in the treatment of autonomous thyroid nodules. 4 years' experience]. / L'iniezione percutanea di etanolo (PEI) nella terapia dei noduli tiroidei autonomi. Esperienza dopo quattro anni.

We treated with PEI 81 patients carriers of autonomous thyroid nodule, 65 toxic and 16 non toxic, all with undetectable serum TSH and suppressed extranodular tissue on scintigraphy. The treatment schedule was: 1-2 sessions per week, 1-8 ml per session, 3-13 sessions in total, In relation to the size and the therapeutic response. The signs of hyperthyroidism disappeared in all cases. Complete cure was obtained in 51 patients; hormonal remission was obtained in 24 patients; partial compensation was obtained in six patients. No recurrences were observed, but two dysphonias lasting three months were reported. PEI seems to be an alternative to surgery and 131I for the ablation of toxic nodules with a volume less than 30 ml.

Clinical experience with a simple screening test for Cushing's syndrome combining the determination of plasma cortisol circadian rhythm with the overnight dexamethasone suppression test.

In 17 normal subjects and 126 patients with various endocrine disorders, including 13 patients with Cushing's syndrome, plasma levels of fluorogenic corticosteroid were measured at 9 AM and midnight, and again at 9 AM the following morning, after the patient had received 1 mg of dexamethasone by mouth immediately after the midnight sampling. Basal morning levels of plasma corticosteroids were of little diagnostic value in differentiating between Cushing's syndrome and non-Cushing's states because of the wide overlap of values observed. At midnight the overlap almost completely disappeared. After overnight suppression, only one patient with a mild form of Cushing's disease had normal (false-negative) results in two of four instances. There were virtually no false-positive results, except for two patients with anorexia nervosa showing minor abnormalities of the test. The results were in general agreement with those of the classic Liddle test. However, one patient with Cushing's disease had repeatedly abnormal responses to overnight suppression and normal responses to the Liddle test. When the inhibitory tests gave equivocal results in the differential diagnosis between exogenous obesity and Cushing's disease due to adrenal hyperplasia, the response of plasma corticosteroids to hypoglycemia, normal in obesity and absent in Cushing's disease, proved to be an excellent ancillary test in differentiating between the two conditions.

Thyroid scintigraphy during antithyroid treatment for autonomous nodules as a means of imaging extranodular tissue.

The scintigraphic appearance of the thyroid gland after a course of methimazole treatment was studied in 22 patients with autonomous hot nodules. After 2-3 months of treatment the extranodular tissue was reactivated in almost every patient. This treatment constitutes an endogenous TSH stimulation test and may be used clinically in selected cases.

Indium-111 pentetreotide lung uptake in infectious lung disease.

Bilateral diffuse lung uptake of In-111 pentetreotide (OCT) was observed during a whole-body scan performed in a 68-year-old woman with Cushing's syndrome and suspected ectopic adrenocorticotropic hormone secretion. A few days later, she was found to have bilateral bacterial pneumonia (of mixed anaerobic origin). Cushing's syndrome was finally proved to be of pituitary origin. The OCT lung uptake in pneumonia probably resulted from tracer binding by somatostatin receptors on the inflammatory leukocytes. Although the rapid wash-out from experimentally induced abscesses does not make OCT a suitable tracer for detecting acute infections, the images and data here reported suggest that infectious lung disease should be excluded before diagnosing lung involvement by neuroendocrine tumors.

Scintigraphic study of extra-adrenal ganglioneuroma in a patient with overlap between multiple endocrine neoplasia types 1 and 2.

A 27-year-old woman was diagnosed with a pituitary prolactinoma. Seven years later, when she was 34, an abdominal mass was incidentally discovered and ascribed to the right adrenal gland on the basis of evidence from ultrasonography, computed tomography, and arteriography. Adrenal scintigraphy with Se-75 selenomethylcholesterol imaged both adrenal glands, but the right gland was distorted, suggesting external compression. I-131 MIBG was not taken up by the mass. At surgery, an extra-adrenal ganglioneuroma was found and excised. This case represents an overlap between multiple endocrine neoplasia types 1 and 2. The failure of the ganglioneuroma to concentrate MIBG was likely caused by secretory inactivity of a biologically mature tumor.

Role of Tc-99m sestamibi scintigraphy in the diagnosis and surgical decision-making process in primary hyperparathyroid disease.

PURPOSE: Ultrasound (US) and scintigraphy are used most frequently of all the available imaging techniques for the preoperative evaluation of patients with possible primary hyperparathyroid disease. The aim of this study was to assess the value of dual-phase Tc-99m MIBI scintigraphy compared with US in the detection of adenomatous or hyperplastic glands and in the surgical decision-making process for patients with a biochemical diagnosis of primary hyperparathyroid disease. METHODS: Ninety-seven patients with increased levels of parathyroid hormone and calcium, and at least 6 months' follow-up after US and scintigraphy, were examined retrospectively to assess the influence of the diagnostic work-up on the therapeutic decision of the referring clinicians and to evaluate the sensitivity of these diagnostic tools in the surgically treated patients. Forty-eight patients underwent surgery. RESULTS: Parathyroid adenomas were found in 43 patients and hyperplasia in 1, whereas 4 patients had no evidence at surgery. The sensitivity and specificity rates were 84.4% and 95.9% for scintigraphy, and 66.6% and 98.6% for US, respectively. Of the 49 nonsurgically treated patients, 35 had negative results with both MIBI and US; only 3 had positive findings with both imaging methods. Patients treated conservatively had significantly lower parathyroid hormone and serum calcium levels than did the patients who had surgery. CONCLUSIONS: The data suggest that the high sensitivity of dual-phase MIBI scintigraphy can improve the detection of hyperfunctioning parathyroid glands. Furthermore, despite the controversy surrounding the use of imaging methods in the preoperative assessment of primary hyperparathyroid disease, these data suggest that the decision of the clinician to order surgery for a patient with a moderate increase of serum PTH level may be influenced by the results of the imaging methods.