Parathyroiditis in the non-obese diabetic mouse--a new finding.

Autoimmune reactions to parathyroid cells have been observed in human autoimmune polyendocrinopathy, but such findings have not been described in animal models of polyendocrine autoimmunity. We report here three cases of lymphocytic infiltrations in 12 parathyroid glands identified in a total of 18 thyroid glands studied in the non-obese diabetic (NOD) mouse. The majority of parathyroid-infiltrating lymphocytes possessed the helper/inducer phenotype as defined by the L3T4 monoclonal antibody. Parathyroiditis was accompanied by lymphocytic thyroiditis only on one occasion, whereas in other cases of thyroiditis, lymphocytic infiltration of the parathyroid was undetectable. We conclude that parathyroiditis in the NOD mouse is part of the wide spectrum of autoimmunity observed in this animal model of diabetes.

Elevated adrenocorticotropic hormone and cortisol levels in a patient with medullary carcinoma of the thyroid containing ectopic immunoreactive corticotropin-releasing hormone and bombesin.

Pituitary adrenocorticotropic hormone-dependent Cushing's syndrome due to ectopic production of corticotropin-refeasing hormone (CRH) or bombesin (gastrin-releasing peptide) is an extremely rare cause of pituitary adrenocorticotropic hormone (ACTH) hypersecretion. We report a patient with elevated ACTH and cortisol levels due to ectopic secretion of both bombesin and CRH by metastatic medullary carcinoma of the thyroid (MCT). A 45-year-old man was investigated because of diabetes insipidus and visual field disturbances due to suprasellar metastasis of the MCT. On physical examination, he was a chronically ill man with a body mass index of 18.5 and was darkly pigmented but without other features typical of Cushing's syndrome. Hypogonadotropic hypogonadism, thyroid-stimulating hormone (TSH) deficiency, and hyperprolactinemia were due to pituitary stalk disorder, in light of these deficiencies, we were surprised to find elevated plasma ACTH, cortisol, and growth hormone (GH) levels throughout the day. Plasma ACTH at 9AM was 118 pg/ml and plasma cortisol was 859 nmol/L. At 12PM, ACTH was 89 pg/ml whereas plasma cortisol was 540 nmol/L. Urinary 17 OH CS were elevated (38 nmol/24 hr). The mean of the four-point day curve for GH was elevated. Plasma electrolytes were normal. The presence of both CRH and bombesin was documented by immunocytologic studies in the metastases (lymph node and suprasellar biopsy). ACTH was not found in any of the metastases. Because of the close proximity of the suprasellar metastasis to the portal pituitary circulation, CRH and bombesin could have been readily provided to the pituitary corticotrophs.

Cushing's disease cycling over ten years.

Cycles of excessive cortisol secretion have been reported interposed with phases of remission lasting from few days to several months. In this study we report a ten year follow up on a patient who had four episodes of hypercortisolism and Cushing's syndrome associated with hypokalemia and edema and three long lasting spontaneous remissions. This was all caused by corticotroph pituitary adenoma. She demonstrated the longest phase of remission yet recorded in this condition, 4.5 years. The precipitating factors for the recurrence in cyclical Cushing's syndrome are not well defined, but the last recurrence in our patient appeared two months after delivery. We have discussed the continuing uncertainty of the standard dynamic tests in the differential diagnosis of Cushing's syndrome.

Massive prolactinoma with galactorrhoea in a prepubertal boy.

An 8 year old prepubertal boy presented with raised intracranial pressure, left proptosis and was noted to have galactorrhoea. Cranial computerized tomography revealed a large pituitary tumour infiltrating the cavernous sinus and left orbit. The serum prolactin was 180,600 mU/l (normal value less than 360 mU/l). Prolactinomas are rare in children and galactorrhoea has not previously been reported in a prepubertal child. The management of massive prolactinomas is difficult, but the child presented has made an impressive response to a combination of treatment with surgery, dopamine agonist therapy and radiotherapy.

The effects of transsphenoidal surgery on endocrine function and visual fields in patients with functionless pituitary tumours.

Twenty-eight patients with functionless pituitary tumours have been treated by transsphenoidal surgery over the last 28 months. Mean age at presentation was 55 years. Tumor size was graded according to the extent of suprasellar extension on CT headscan from above the interclinoid line: four were small, 15 medium and nine large. Before surgery in 25 per cent of patients visual acuity and visual fields were normal. In the immediate postoperative period, 24 per cent of the patients with visual defects before surgery had normal vision, and in 38 per cent of the others it was improved. Six months after surgery, there had been further improvement; 43 per cent had normal vision and 48 per cent showed an overall improvement. In no patient did vision deteriorate following surgery. In the patients who presented with visual symptoms of one year or less, there was no correlation between the length of symptoms and the extent of visual recovery after surgery. Average age of the patients with full visual recovery was 47 +/- 4 years (mean +/- SEM); average age of the patients with only partial visual recovery was 63 +/- 3 years. Prolactin levels before surgery were elevated in 77 per cent of patients and fell significantly after operation, remaining elevated in 28 per cent of patients six months later. Fifty per cent of patients were treated with long-term hormone replacement therapy. Transsphenoidal surgery led to improved vision in the majority of patients, the results being comparable with those obtained with transfrontal surgery. Surgical complications were few, and long-term morbidity low. We suggest that the first-line treatment for patients with functionless pituitary tumours should be transsphenoidal surgery, even when large suprasellar extensions are present.

Demonstration of desacetyl alpha-melanocyte-stimulating hormone in fetal and adult human anterior pituitary corticotrophs.

Immunocytochemistry, radioimmunoassay and high-performance liquid chromatography (HPLC) techniques have been used in combination to investigate the presence of immunoreactive (ir)-alpha-MSH in the normal human pituitary gland, and to investigate the possible origin of these cells from the fetal pars intermedia. Two separate antisera to alpha-MSH were employed in immunocytochemistry to distinguish between authentic alpha-MSH and the desacetyl form. Only desacetyl alpha-MSH was detected in the pituitary gland of fetal and adult man, in both the pars (zona) intermedia and the pars anterior. In the fetus, a large proportion of the ACTH-containing cells of the anterior lobe also contained ir-alpha-MSH, while ir-alpha-MSH containing cells were more sparse in adults. Radioimmunoassay of acid extracts of adult pituitary tissue showed alpha-MSH levels representing less than 0.05% of the ACTH content of the gland. HPLC analysis of these extracts confirmed that only the desacetyl form was present. These results suggest that alpha-MSH peptides are synthesized by anterior lobe cells of the human pituitary gland, which are not derived from the fetal pars intermedia. Possible regulatory mechanisms affecting cells which contain ir-alpha-MSH are discussed, and by comparison with the intermediate lobe of other species it is concluded that there is little evidence for a true intermediate lobe in the human pituitary gland.

Peptides related to alpha-melanocyte-stimulating hormone are commonly produced by human pituitary corticotroph adenomas: no relationship with pars intermedia origin.

The presence of immunoreactive (ir)-alpha-MSH has been investigated by immunocytochemistry in 24 pituitary adenomas and one case of corticotroph hyperplasia causing Cushing's disease, in four adenomas causing Nelson's syndrome, and in ten 'silent' corticotroph adenomas. It was found that a high proportion of these adenomas have a population of cells containing ir-alpha-MSH in addition to ir-ACTH. In some instances, these adenomas were clearly not associated with the residual intermediate lobe of the pituitary. Radioimmunoassay of plasma from patients with Cushing's disease or Nelson's syndrome showed elevated levels of ir-alpha-MSH in the majority of cases. Characterization of the ir-alpha-MSH in adenoma cells by immunocytochemistry, using an antiserum selective for acetylated forms of alpha-MSH, suggested that only the desacetyl form was present in each case examined. High-performance liquid chromatography of adenoma tissue extracts revealed material co-eluting with acetylated forms of alpha-MSH in only one of six cases. These results have been compared with corticotroph adenomas in animal pituitary glands, and it is concluded that the presence of alpha-MSH peptides cannot be used as a marker for intermediate lobe tumours, and that desacetyl alpha-MSH is commonly produced by corticotroph adenomas.

Increased production of alpha-melanocyte-stimulating hormone in the pituitary gland of patients with untreated Addison's disease.

There is evidence that peptides related to alpha-melanocyte-stimulating hormone (alpha-MSH) are involved in regulating the zona glomerulosa of the adrenal cortex in certain species. We have investigated the amount of immunoreactive (IR)-alpha-MSH in the human pituitary gland of patients suffering from Addison's disease. We show increased numbers of cells containing demonstrable IR-alpha-MSH in the anterior lobe in these patients. Using an antiserum with specificity for the acetylated N-terminus of alpha-MSH we suggest that the major form present is desacetyl-alpha-MSH. These findings are in keeping with a role for anterior lobe derived desacetyl-alpha-MSH in the regulation of the human adrenal cortex.

Development of folliculo-stellate cells in the human pituitary.

The development of the folliculo-stellate cell in human fetal pituitaries has been investigated by immunocytochemical methods for S-100 protein and glial fibrillary acid protein. S-100 positivity was first observed in pars intermedia cells in a 13-week fetus. Staining with this antiserum is seen in cells of the pars distalis after 15 weeks. Glial fibrillary acid protein was not apparent until 18 weeks, when only cells in the pars intermedia were stained. These cells were not seen in the pars distalis before 28 weeks' gestation, but were present in a 39-week specimen and in a 5 day old baby. In most pituitaries examined, cells staining for S-100 and glial fibrillary acid protein were more concentrated in the pars intermedia than the pars distalis. These results suggest that folliculo-stellate cells in the human pituitary originate in the neurally associated facet of the pars intermedia and pass through this lobe to reach the pars distalis. Since these cells stain for glial related antigens, they may be a modified form of glial cell and arise in the neuroectoderm. Evidence for this hypothesis is given by a lack of both S-100 and glial fibrillary acid protein in the pituitaries of three anencephalic pituitaries. Differences in the timing of S-100 and glial fibrillary acid protein immunoreactivity may be related to either developmental aspects of the folliculo-stellate cell, or to the presence of two distinct cell types.

A bromocriptine-responsive corticotroph adenoma secreting alpha-MSH in a patient with Cushing's disease.

Clinical and in-vitro investigations have been performed on a corticotroph adenoma removed from a patient suffering from Cushing's disease. Prior to surgery, the patient's Cushing's disease had been successfully controlled, clinically and biochemically, by long term administration of bromocriptine. After selective adenomectomy, tumour tissue was investigated by a perfused isolated cell column technique. It was shown that the tumour cells secreted immunoreactive- (IR)- ACTH and IR-alpha-MSH and that the release of both peptides was promptly suppressed by dopamine. Chromatographic analysis of the secreted IR-alpha-MSH revealed a high proportion of acetylated alpha-MSH; smaller amounts of desacetyl alpha-MSH and diacetyl alpha-MSH were present. The relevance of these findings to the proposal that certain corticotroph adenomas are derived from the intermediate lobe of the pituitary is discussed. It is concluded that there is little direct evidence for involvement of the residual zona intermedia of the adult human pituitary in the development of Cushing's disease.

A phaeochromocytoma presenting with Cushing's syndrome associated with increased concentrations of circulating corticotrophin-releasing factor.

The case is described of a 61-year-old male who presented with hypertension and Cushing's syndrome which resolved on excision of a unilateral adrenal mass. Histology of the tumour revealed a benign phaeochromocytoma which immunostained for corticotrophin-releasing factor (CRF-41) but not for ACTH. Preoperative plasma concentrations of immunoreactive CRF-41 were increased, and gradients for both CRF-41 and ACTH were demonstrated across the tumour. Post-operatively, CRF-41 was undetectable in plasma. The tumour contained high concentrations of immunoreactive CRF-41 which co-eluted with synthetic human CRF-41 on reversed-phase high-performance liquid chromatography. Tumour CRF-41 stimulated the release of ACTH in a dose-dependent manner from isolated rat anterior pituitary cells. We conclude that this tumour secreted CRF-41 and ACTH and had the capacity to produce ACTH-dependent Cushing's syndrome directly by secreting ACTH and indirectly by secreting CRF-41 to stimulate ACTH secretion from the anterior pituitary.

The distribution of immunoreactive alpha-melanocyte-stimulating hormone cells in the adult human pituitary gland.

It has been suggested that a proportion of the adenomas and the nodular hyperplasia of cells in the pituitary gland in cases of Cushing's disease are derived from cells of the pars intermedia rather than the pars anterior. The evidence can be summarized as follows: the posterior site of adenoma or nodular hyperplasia in the pituitary, the innervation of cells and the suppressive response to the dopamine agonist bromocriptine in vivo or to dopamine in vitro. All these observations infer analogy with cells of the pars intermedia of other species, which are controlled by direct neural tonic dopaminergic inhibition. The adult human pituitary gland, however, does not possess a morphologically distinct pars intermedia, due to regression of the rudimentary fetal pars intermedia after birth, with mixing of cells into the pars anterior and pars nervosa. Since cells of the pars intermedia characteristically synthesize alpha-MSH, we have studied this peptide in order to assess the occurrence and distribution of intermedia-derived cells in the adult human pituitary. Sections from 100 pituitaries, removed at autopsy, were stained by an indirect immunoperoxidase technique using non-cross-reacting antisera specific for alpha-MSH and ACTH. Immunoreactive alpha-MSH (IR-alpha-MSH) cells were found in a total of 97 specimens. Of these, only ten cases showed a marked concentration of IR-alpha-MSH cells in the zona intermedia. In the majority of pituitaries, IR-alpha-MSH cells were more commonly seen in the pars anterior than in the zona intermedia; in 41 cases, IR-alpha-MSH cells were completely absent from the zona intermedia.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunocytochemical study of 18 tumours causing ectopic Cushing's syndrome.

Eighteen cases of Cushing's syndrome caused by ectopic production of peptide hormones were investigated by histological and immunocytochemical methods and the findings correlated with clinical and biochemical observations. Immunocytochemistry showed immunoreactive adrenocorticotrophic hormone (ACTH) or peptides derived from the ACTH precursor (pro-opiomelanocortin (POMC], or both, in a total of 10 cases: five of these also contained immunoreactive-alpha-melanocyte stimulating hormone, indicating more extensive translational processing of POMC than normally occurs in healthy corticotrophs of the anterior pituitary; in two further cases peptides capable of stimulating ACTH release from the anterior pituitary were present. In the remaining six cases immunocytochemistry failed to show the presence of ACTH, other POMC derived peptides, or peptides with ACTH releasing properties. These findings correlate well with the histological and clinical observations, in that the six tumours had been clinically overt, caused rapid death, and histologically seemed to be highly malignant. In contrast, the 12 other tumours were occult to radiological examination, patients had a much improved survival rate, and histologically the tumours seemed to be less aggressive. All but one of the tumours in this series showed a degree of neuroendocrine differentiation, indicated by the presence of neuron specific enolase. These results suggest that one feature of highly malignant tumours, which cause an ectopic endocrine syndrome, is a high secretion of peptide hormones, leaving amounts that are too small to be shown by immunocytochemistry.

Diagnosis and management of ACTH-dependent Cushing's syndrome: comparison of the features in ectopic and pituitary ACTH production.

The clinical features, diagnosis and management of 16 consecutive patients with ectopic ACTH production are described and biochemical data are compared with those of 48 consecutive patients with pituitary-dependent Cushing's disease. In 10 cases the ectopic ACTH secreting tumour was completely occult to routine clinical and radiological investigation, and no basal or dynamic investigation of adrenal-pituitary function was able clearly to differentiate these patients from those with Cushing's disease. High dose dexamethasone suppression testing assessed by plasma cortisol was usually helpful but unexpected responses were seen in both diagnostic groups; the metyrapone test yielded no useful information and should now be abandoned. Hypokalaemia was seen in all patients with ectopic ACTH production but in only 10% of those with Cushing's disease who were not on diuretics at presentation. Successful diagnosis and tumour localization was most frequently achieved by a combination of CT scanning of the chest and abdomen and venous catheter sampling for ACTH. All patients in whom the ectopic ACTH-secreting tumour was obvious at presentation died of their primary tumour within 8 months, whereas seven of the 10 patients with occult tumours at presentation are alive 1.5-16.5 years later, and appear cured. Occult ectopic ACTH secretion may be impossible to distinguish from pituitary Cushing's disease. Multiple and repeated investigations are often required to make this differential diagnosis, essential for appropriate therapy.

Histopathology of the pituitary.

The cytoplasmic secretory granules of corticotrophs in the anterior pituitary are basophil in trichrome stains and periodic acid-Schiff positive in the histochemical stain for glycoprotein due to their content of the glycosylated 16 000 N-terminal fragment of the precursor protein proopiomelanocorticotrophin (POC). The granules show a positive immunocytochemical reaction to antibodies raised against ACTH, beta-endorphin and N-terminal fragments of POC. A small subset of corticotrophs contains immunoreactive alpha MSH in addition. Immunocytochemistry shows the corticotrophs to constitute about 15-20% of the anterior pituitary cells arranged both singly and in clumps. They are distributed in the median wedge and anteriorly, laterally and posteriorly adjacent to the pars nervosa which is often 'invaded' by corticotroph basophils. The alpha MSH subset is prominent in the rudimentary intermediate lobe and is scattered anteriorly in the pituitary of the human fetus. Crooke cell hyalinization is associated with pathologically maintained hypercortisolaemia and with glucosteroid therapy. The hyalinization is demonstrated in ultrastructure to be due to massive accumulation of intermediate cytoplasmic filaments 7-8 nm in diameter that are normally present in only small number. The change is associated with a varying degree of loss of secretory granules. In untreated Addison's disease there is a marked increase in the number of corticotrophs, many of which are arranged in distended alveoli to form micronodules. The vast majority of cases of pituitary-dependent Cushing's disease and all cases of Nelson's syndrome are associated with a basophil or chromophobe adenoma. These give a positive immunocytochemical reaction with anti-ACTH, beta-endorphin and N-terminal POC. In ultrastructure the cells of the chromophobe adenomas are seen to contain sparse secretory granules that are usually smaller than those in the chromophil adenomas. There are only very few reports of pituitary-dependent Cushing's disease found to be due to immunocytochemically confirmed corticotroph hyperplasia with or without a corticotroph adenoma. A few cases have been described in which the adenoma cells show Crooke's hyalinization, associated in one example with secretion of a big ACTH found more typically in ectopic ACTH-secreting tumours. A group of cases due to corticotroph adenoma has been reported whose excessive ACTH secretion is reduced by treatment with the dopamine agonist bromocriptine, in which it is suggested that the tumour cells arise from a subset of corticotrophs of pars intermedia origin.(ABSTRACT TRUNCATED AT 400 WORDS)

The relationship between serum prolactin and immunocytochemical staining for prolactin in patients with pituitary macroadenomas.

We have studied the relationship between mean pretreatment levels of serum prolactin and the presence of positive immunohistochemical staining for prolactin in the pituitary tumours of 55 patients. Pretreatment serum prolactin was significantly higher in patients with tumours showing many prolactin immunostaining cells than in those with none (P less than 0.001). When the pretreatment serum prolactin exceeded 6000 mU/l, the tumours contained over 90% of prolactin positive cells; one patient was an exception who had received long-term high dose bromocriptine therapy, and her tumour showed only occasional cells with positive staining. When the pretreatment serum prolactin level was under 2500 mU/l, a tumour was found which showed either no cells or fewer than 1% of cells which stained for prolactin. There was no significant difference in pretreatment serum prolactin levels between 11 patients with craniopharyngiomas and 34 patients with pituitary macroadenomas showing no prolactin immunostaining. Seventy-one percent (32) of the 45 patients with craniopharyngiomas or tumours with negative immunostaining for prolactin, had raised pretreatment serum prolactin levels (above 360 mU/l) although this was usually only slightly elevated; the levels exceeded 2500 mU/l in six (13%) of them (two craniopharyngiomas, four pituitary tumours) but in none did the levels exceed 6000 mU/l. Four of the 55 pituitary tumours showed occasional cells (less than 1%) that stained positively for growth hormone. In none of the patients with these tumours was there evidence of acromegaly or pathologically elevated circulating growth hormone levels.

Bombesin-like peptides in human endocrine tumors: quantitation, biochemical characterization, and secretion.

Bombesin-like immunoreactivity (BLI) in 20 human endocrine tumors was studied using an antiserum directed toward the C-terminal region of bombesin. Additionally, plasma BLI was assayed in normal subjects and patients with known BLI-containing tumors. In 7 tumors (medullary carcinoma of the thyroid, n = 2; carcinoid of the lung, n = 3; hepatic carcinoid, n = 1; pheochromocytoma, n = 1), the BLI content ranged from 6-2000 pg/mg wet wt of tissue. Sephadex G-50 gel chromatography of tumor extracts under acid-dissociating conditions revealed 2 peaks of BLI: 1 coeluting with porcine gastrin-releasing peptide (GRP) and 1 with bombesin. Reverse phase ODS silica HPLC analysis of the G-50 peaks using a methanol-trifluoroacetic acid gradient showed that human tumor BLI more closely resembled porcine GRP and its C-terminal fragment GRP-(14-27) than bombesin itself. Partial tryptic digestion of the tumor GRP-like peptide generated a product which, on HPLC, was similar to GRP-(14-27). Elevated plasma BLI was detected in the peripheral circulation of three subjects and in the vessels draining the tumor metastases of one of these patients. BLI was undetectable in normal subjects. These results indicate 1) that BLI is present in and may be secreted by various human endocrine tumors, and 2) that human tumor BLI closely resembles porcine GRP and its C-terminal fragment GRP-(14-27).

The effect of dopamine agonist therapy on large functionless pituitary tumours.

Fifteen patients (12 male) with large pituitary tumours and serum prolactin levels below 1000 mU/l were given dopamine agonist therapy (bromocriptine, mesulergine or pergolide) for a mean of 9 months (range 3-36 months). Serum prolactin became undetectable in all. Despite this, significant suprasellar extensions and any associated neurological defect remained in 14 patients, who therefore were referred for surgery. In one patient there was evidence of spontaneous pituitary infarction unrelated to dopamine agonist therapy. At operation 12 patients had apparently functionless pituitary adenomas which failed to immunostain for prolactin, one had an epidermoid cyst and one a Rathke's pouch cyst. We conclude that patients with large pituitary tumours and only a mildly elevated serum prolactin are unlikely to have prolactinomas, and that such tumours are not likely to show significant tumour shrinkage with medical treatment with dopamine agonists.