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Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In one case of pituitary basophil adenoma, the majority of the cells contains numerous small granulations which, by using immunohistoenzymatic technique, react with alpha, 17-39 ACTH and beta, MSH antisera. The reaction with anti beta, 1-24 ACTH is negative. The radioimmunoassay of ACTH reveals an increase of plasmatic ACTH, but the cortisol cycle stays low. This data suggests that this functional adenoma releases a product of which has an immunological relationship with ACTH, without biological activity.
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PMID:[Pituitary adenoma with alpha, 17-39 ACTH and beta, MSH cells, without hypercorticism (author's transl)]. 20 17

In order to characterize more accurately the relationship between immunoreactive beta-MSH ("BETA-MSH") and the lipotrophins (LPH) we attempted to investigate the gel filtration and the immunological characteristics of "beta-MSH" in the plasma of patients with Nelson's syndrome and Addison's disease as well as in the culture medium from a human corticotrophic adenoma using a sensitive radioimmunoassay from human beta-MSH. When added either to hormone free plasma or to a plasma from a patient with Nelson's syndrome all the human beta-MSH (hbeta-MSH) elutes from a Sephadex G-50 column as a single peak in a volume corresponding to its molecular weight. In contrast plasma "beta-MSH" in 3 patients with Nelson's syndrome and one patient with Addison's disease almost completely elutes in a volume corresponding to a molecular weight range of 6000-10 000; no "beta-MSH" can be detected in its normal elution volume. Drastic pH change (8.2 to 2.3) does not significantly alter the elution pattern. Chromatography of a corticotrophic adenoma culture medium gave a similar pattern of "beta-MSH" with a main peak in the molecular weight range of 6000-10 000. In our radioimmunoassay the culture medium and purified hbeta-LPH gave parallel displacement curves for [125I]hbeta-MSH. It is suggested that hbeta-LPH or a closely related substance is the main material responsible for "beta-MSH" immunoactivity.
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PMID:Immunoreactive beta-MSH in human plasma and in a corticotrophic adenoma culture medium. Its relation to the lipotrophins. 21 10

A case of Cushing's syndrome associated with a bronchial adenoma treated eight years before with bilateral adrenalectomy was cured by surgical excision of the bronchial adenoma. A discussion of clinical and hormonal features of this lesion is presented. It is concluded that this tumor manifested a capability of synthesizing and releasing substances which are chemically and biologically similar to adrenocorticotropic hormone andmelanocyte-stimulating hormone (MSH). Stimulation of the adrenal cortex by this material results in hyperplasia and hypersecretion, and stimulation of the melanocytesy MSH resulted in excessive pigmentation. Acknowledgment: We are indebted to Doctors Wendell Nicholson, David N. Orth, and Grant W. Liddle of Vanderbilt University for determinations of ACTH and MSH levels and to Mrs. E.P. Jessup for assistance in preparation of statistical data for this manuscript.
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PMID:Cushing's syndrome associated with bronchial adenoma. 83 99

It has been hypothesized by Lamberts and coworkers in their analysis of 15 cases that adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas may be derived from either the anterior lobe or the intermediate lobe. The intermediate lobe type of Cushing's disease is thought to be controlled through a hypothalamic pathway and is characterized by hyperprolactinemia; suppressibility of cortisol with bromocriptine, and lower sensitivity to dexamethasone. The authors investigated the validity of this hypothesis in 125 cases of ACTH-secreting pituitary microadenomas by analyzing the endocrine findings, the locations of the microadenomas, and alpha-melanocyte stimulating hormone (alpha-MSH) immunoreactivity in the adenoma cells. No significant differences in the basal hormone levels, cortisol suppressibility with bromocriptine, sensitivity to dexamethasone, and recurrence rate were observed between patients with the microadenoma adjacent to the posterior lobe (considered typical of the intermediate lobe-derived tumor) or those with the microadenoma located in the anterior lobe. The locations of the microadenoma were not correlated with alpha-MSH immunoreactivity in the adenoma cells. No significant differences in endocrine findings were noticed between adenomas positive or negative for alpha-MSH. Thus, Cushing's disease cannot be simply divided into either the anterior lobe type or the intermediate lobe type by endocrinological evaluation as described by Lamberts, et al.
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PMID:Endocrinological evaluation of ACTH-secreting pituitary microadenomas: their location and alpha-melanocyte stimulating hormone immunoreactivity. 131 55

An immunoradiometric assay (IRMA) for the direct measurement of the precursors of ACTH in unextracted human plasma has been developed and evaluated clinically in normal subjects and patients with disorders of the hypothalamic-pituitary-adrenal axis. The IRMA is based on an iodinated monoclonal antibody to ACTH and a monoclonal antibody to gamma MSH coupled to Sephacryl S300. The assay detects only peptides containing both epitopes, i.e. POMC (31K) and pro-ACTH (22K). The reference standard was partially purified POMC from culture medium of human corticotroph adenoma cells. The detection limit (greater than +2.5SD of the 0 standard) was 2.0 pmol/L and the within-assay coefficient of variation was less than 10% between 29 and 2600 pmol/L. Plasma concentrations of ACTH precursor peptides in 11 normal subjects sampled at 0930 h ranged from 5-34 pmol/L. The concentrations in the patient groups studied were: 260-2300 pmol/L in 5 patients with the ectopic ACTH syndrome associated with small cell lung cancer, less than 2.0-104 pmol/L in 10 patients with pituitary-dependent Cushing's disease, 23 pmol/L in a patient with Nelson's syndrome, and 3.0-230 pmol/L in 5 patients with Addison's disease. We conclude that this IRMA offers a simple and reliable method for measuring ACTH precursors in unextracted plasma. The proportionately greater elevation of ACTH precursors compared to ACTH in patients with the ectopic ACTH syndrome associated with small cell lung cancer but not in pituitary-dependent Cushing's syndrome, suggests that this assay may be clinically useful.
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PMID:Direct measurement of the precursors of adrenocorticotropin in human plasma by two-site immunoradiometric assay. 284 55

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)
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PMID:Histopathology of the pituitary. 300 76

We have studied the diurnal rhythm of pars distalis and pars intermedia-type immunoreactive (IR)-POMC peptides and cortisol in 3 normal dogs and 1 dog with Cushing's syndrome and have documented the responses to a variety of agents in 42 dogs with Cushing's disease, 2 of which were known or presumed to have pars intermedia tumors and another of which had both pars distalis and pars intermedia adenomas, and in 20 dogs with adrenocortical adenomas causing Cushing's syndrome. The normal dogs did not have a diurnal plasma POMC peptide rhythm; the dog with Cushing's disease appeared to have a similar number of secretory episodes of increased amplitude. Plasma POMC peptides and cortisol in animals with Cushing's disease did not suppress normally with low dose dexamethasone. Five animals with Cushing's disease did suppress with high dose dexamethasone, the dog with dual adenomas suppressed only partially, and 1 dog with a pars intermedia adenoma did not suppress at all. The response to insulin-induced hypoglycemia was similar in normal dogs and 4 dogs with Cushing's disease, but 3 animals with adrenal tumors did not respond. The response to metyrapone was normal in 6 dogs with Cushing's disease and, surprisingly, in 1 with adrenal tumor. Arginine vasopressin stimulated POMC peptide secretion in normal and 6 Cushing's dogs, as well as alpha MSH, a pars intermedia-type POMC peptide, in a dog presumed to have a pars intermedia tumor. Ovine CRF stimulated pars distalis-type POMC peptide secretion in normal dogs and 17 dogs with Cushing's disease, but not in 15 dogs with adrenal tumor; IR-alpha MSH was unaffected. TRH appeared to stimulate IR-ACTH in normal animals, but not in those with Cushing's disease. Dopamine had no apparent effect in 2 normal and 1 Cushing's dogs. Initial plasma disappearance t1/2 values of IR-ACTH and lipotropin were 22-27 min. In summary, responses in normal and Cushing's dogs were generally what would be predicted from previous human and animal studies, but some of those in animals with pars intermedia tumors and even in normal dogs were different from what had been anticipated. Canine Cushing's syndrome provides an interesting model for an uncommon human disorder.
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PMID:Plasma immunoreactive proopiomelanocortin peptides and cortisol in normal dogs and dogs with Cushing's syndrome: diurnal rhythm and responses to various stimuli. 312 32

A non-ACTH aldosterone-stimulating factor(s) has been implicated in the pathogenesis of idiopathic hyperaldosteronism (IHA). Although this factor has not been fully characterized, some evidence suggests that it may be related to a pro-gamma-melanotropin (pro-gamma-MSH), derived from the NH2-terminal region of pro-opiomelanocortin. In the present study, plasma immunoreactive (IR-) gamma-MSH levels at 0800 h in patients with IHA were evaluated (90 +/- 17 fmol/ml; range: 13-173 fmol/ml) and found to be significantly higher (P less than 0.05) than those in subjects with aldosterone-producing adenomas (33 +/- 8 fmol/ml), essential hypertension (33 +/- 6 fmol/ml), and normotensive controls (19 +/- 2 fmol/ml). Seven of nine IHA subjects had circulating IR-gamma-MSH levels above the normal range (greater than 35 fmol/ml). In plasmas sampled at 1200 h, IR-gamma-MSH was significantly higher in patients with IHA (95 +/- 26 fmol/ml) and adenomas (63 +/- 23 fmol/ml), as compared with essential hypertensives (31 +/- 6 fmol/ml) and normotensives (19 +/- 3 fmol/ml). Mean plasma IR-ACTH, plasma cortisol, and urinary cortisol levels did not differ significantly between any of these groups. In order to evaluate the effect of a pro-gamma-MSH in vitro, adrenal adenoma tissue was obtained from two patients, one with elevated IR-gamma-MSH (61 fmol/ml) and a second with low IR-gamma-MSH (12 fmol/ml). Aldosterone secretion by dispersed adenoma cells from the former, but not the latter, underwent a fourfold dose-dependent (10(-14)-10(-9) M) increase in response to human Lys-gamma 3-MSH. These data suggest that a pro-gamma-MSH may be implicated as a pathogenic factor in a subset of patients with primary aldosteronism, particularly among those differentially diagnosed as having IHA.
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PMID:Plasma immunoreactive gamma melanotropin in patients with idiopathic hyperaldosteronism, aldosterone-producing adenomas, and essential hypertension. 401 76

Fragments of the pituitary adenoma of a patient with Cushing's disease were maintained in defined culture medium. Immunoreactive (IR) ACTH, IR alpha-MSH, IR beta-lipotropin (beta-LPH), IR beta-endorphin, and IR gamma-MSHs secreted from the adenoma were studied with gel permeation chromatography and the respective RIAs. The adenoma secreted roughly equimolar quantities of IR beta-LPH plus IR beta-endorphin, IR gamma 3-MSHs, and IR ACTHs. It also secreted IR alpha-MSH as well as IR gamma 1-MSH, although in a much lower concentration than the above four peptides. The secreted gamma 3-MSH-like peptides were found to be glycosylated. The secretion pattern suggests that this particular adenoma processes the pro-opiomelanocortin molecule in pathways which encompass those of both the pars distalis and the pars intermedia.
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PMID:Secretion pattern of pro-opiomelanocortin-derived peptides by a pituitary adenoma from a patient with Cushing's disease. 625 45

An adrenal cortex adenoma, surgically removed from a female patient with primary aldosteronism, was used to examine the effect of ACTH, angiotensin II, gamma 3-MSH, and the N-terminal fragment of pro-opiomelanocortin purified from porcine anterior pituitaries on aldosterone release in vitro. Primary cultures of tumor cells were incubated as a monolayer in a 96-well microtitration plate and the aldosterone release was measured in the incubation medium after 2 h of incubation in the presence of absence of different concentrations of the peptides. On a molar basis, the N-terminal portion of pro-opiomelanocortin seems to have the highest activity of all of the peptides assayed.
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PMID:Effect of N-terminal portion of pro-opiomelanocortin on aldosterone release by human adrenal adenoma in vitro. 626 59


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