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Esteban F, Ruiz-Avila I, Vilchez R, Gamero C, Gomez M, Mochon A. Ectopic pituitary adenoma in the sphenoid causing Nelson's syndrome. J Laryngol Otol 1997; 111:565-7. [PMID: 9231094 DOI: 10.1017/s0022215100137922] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
An ectopic functioning pituitary in the sphenoid is an extremely rare occurrence, and even rarer is pituitary adenoma causing symptoms of Nelson's syndrome. A case is presented of a young female diagnosed and treated in our clinic. The only functioning hypophyseal tissue was detected inside the sphenoid, as the pituitary gland had been radiated because of Cushing's syndrome 10 years before and imaging studies revealed an empty sella.
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102
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Garrel G, McArdle CA, Hemmings BA, Counis R. Gonadotropin-releasing hormone and pituitary adenylate cyclase-activating polypeptide affect levels of cyclic adenosine 3',5'-monophosphate-dependent protein kinase A (PKA) subunits in the clonal gonadotrope alphaT3-1 cells: evidence for cross-talk between PKA and protein kinase C pathways. Endocrinology 1997; 138:2259-66. [PMID: 9165009 DOI: 10.1210/endo.138.6.5187] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have shown previously that protein kinase A (PKA) subunit levels are regulated by activation of PKA or protein kinase C (PKC) in anterior pituitary cells. GnRH also influenced PKA subunit levels, suggesting that hormonal regulation occurs in gonadotrophs, and therefore, we have reexamined this question using the clonal gonadotrope-derived cell line (alphaT3-1 cells). Western blot analysis, using specific immunoaffinity purified immunoglobulins, revealed expression of catalytic (Cat) and regulatory type I (RI) and type II (RII) subunits of PKA in these cells. Activation of adenylyl cyclase (AC) with forskolin, or of PKC with tetradecanoyl phorbol acetate (TPA), caused a rapid (detectable at 0.5-1 h) and concentration-dependent loss of all PKA subunits. Forskolin (10-100 microM) reduced Cat and RI by 60% and RII by 30%, whereas TPA (0.1-1 microM) reduced Cat and RII by 50% and RI by 40%. Simultaneous activation of PKA and PKC caused the expected dose-dependent reductions in Cat, and the effects of forskolin or TPA were nearly additive. RI and RII were reduced similarly by 10 nM TPA, whereas 100 nM TPA tended to prevent the reduction of RI or RII caused by forskolin. GnRH, which activates phosphoinositidase C and not AC in these cells, caused a clear loss of Cat or RII at all concentrations tested and of RI at 0.1 nM. Pituitary adenylate cyclase-activating polypeptide 38, which acts via PVR-1 receptors to stimulate both phosphoinositidase C and AC in these cells, also caused a clear dose-dependent decrease in Cat, RI, and RII, although higher concentrations were needed for the latter effects. Together, the data demonstrate that catalytic and regulatory subunits of PKA are subject to both hormonal and receptor-independent regulation in alphaT3-1 cells, reinforcing the possibility that such effects occur in nonimmortalized gonadotropes. Whereas the effects of PKA activators very likely involve proteolytic degradation of the dissociated PKA holoenzyme, the effects of TPA and GnRH occur in the absence of cAMP elevation by unknown mechanisms. Whatever the mechanisms involved, the data reveal a mechanism for cross-talk between phosphoinositidase C and AC-mediated hormonal signals, in which PKC activation seems to play a pivotal role.
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Cortright DN, Goosens KA, Lesh JS, Seasholtz AF. Isolation and characterization of the rat corticotropin-releasing hormone (CRH)-binding protein gene: transcriptional regulation by cyclic adenosine monophosphate and CRH. Endocrinology 1997; 138:2098-108. [PMID: 9112410 DOI: 10.1210/endo.138.5.5128] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The CRH-binding protein (CRH-BP) antagonizes the ACTH-releasing activity of the neuropeptide CRH in vitro. However, the function of CRH-BP in vivo and the molecular mechanisms that regulate CRH-BP expression are not well understood. In this study, the rat CRH-BP gene was characterized, and CRH-BP promoter sequences were identified. The rat CRH-BP gene spans almost 12 kilobases and contains 7 exons. Ribonuclease protection experiments indicate that transcription of the CRH-BP gene initiates at multiple sites in rat cerebral cortex. Transfection experiments with CRH-BP-reporter constructs, containing 88-3500 bp 5' flanking and 66 bp 5' untranslated DNA from the rat CRH-BP gene, demonstrate basal promoter activity in multiple cell lines. CRH-BP-reporter constructs also demonstrate positive regulation of promoter activity by cAMP in a variety of cell lines and by CRH in cells expressing the CRH receptor. The DNA sequences between -341 and -88 bp, including the cAMP response element-like sequence at -127 bp, are required for maximal cAMP and CRH regulation of CRH-BP promoter activity. These studies suggest that CRH-BP transcription in vivo may be positively regulated by cAMP and CRH.
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104
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Miller CC, Williamson LH, Miller-Liebl DM, Thompson FN. Lactation associated with acidophilic pituitary adenoma, pheochromocytoma, and cystic endometrial hyperplasia in two goats. J Am Vet Med Assoc 1997; 210:378-81. [PMID: 9057922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Two unbred adult female goats were examined for persistent, inappropriate lactation. Prostaglandin F2 alpha treatment was ineffective in relieving the condition. Over 5 months, 1 goat developed evidence of CNS disease; this same goat had persistently high serum prolactin concentrations. At necropsy, both goats had an acidophilic adenoma of the pars distalis, a condition that, to our knowledge, has not previously been reported in goats. In addition, both goats had pheochromocytomas and cystic endometrial hyperplasia, conditions that are rarely reported in small ruminants. The inciting cause of inappropriate lactation in goats can be difficult to determine. Pituitary adenomas should be suspected when treatment with prostaglandins is unsuccessful, signs of CNS disease develop, or persistently high serum prolactin concentrations are detected.
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Abstract
One hundred and twenty-four cases of lymphocytic adenohypophysitis have been reported since 1962. Nearly 60% of the cases in women involved inset of the disease in relation to pregnancy. Headache and visual field defects were the most frequent symptoms. Most patients showed signs of either isolated or multiple anterior pituitary hormone deficiency. ACTH secretion was impaired the most frequently, followed by TSH, gonadotropins, GH and PRL secretion. One third of the cases involved hyperprolactinemia. Tissue from patients with lymphocytic infundibuloneurohypophysitis, also suffering from DI, revealed lymphocytic inflammation limited to the infundibulum, stalk, and neurohypophysis. Twenty of these 124 lymphocytic adenohypophysitis patients developed DI before treatment, and neuroimaging studies revealed thickening of the pituitary stalk in some. At least in a few cases, chronic lymphocytic infiltration occurred in both the infundibuloneurohypophysitis and adenohypophysis. Although both lymphocytic adenohypophysitis and infundibuloneurohypophysitis may be caused by autoimmune disorders, the antigens involved may differ.
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106
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BARTKE A. HISTOLOGY OF THE ANTERIOR HYPOPHYSIS, THYROID AND GONADS OF TWO TYPES OF DWARF MICE. ACTA ACUST UNITED AC 1996; 149:225-35. [PMID: 14173795 DOI: 10.1002/ar.1091490206] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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107
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ADAMS JH, DANIEL PM, PRICHARD MM. SOME EFFECTS OF TRANSECTION OF THE PITUITARY STALK. BRITISH MEDICAL JOURNAL 1996; 2:1619-25. [PMID: 14213072 PMCID: PMC1816815 DOI: 10.1136/bmj.2.5425.1619] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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108
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SALAZAR H, PETERSON RR. MORPHOLOGIC OBSERVATIONS CONCERNING THE RELEASE AND TRANSPORT OF SECRETORY PRODUCTS IN THE ADENOHYPOPHYSIS. ACTA ACUST UNITED AC 1996; 115:199-215. [PMID: 14210292 DOI: 10.1002/aja.1001150202] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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109
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Pereda MP, Goldberg V, Chervín A, Carrizo G, Molina A, Andrada J, Sauer J, Renner U, Stalla GK, Arzt E. Interleukin-2 (IL-2) and IL-6 regulate c-fos protooncogene expression in human pituitary adenoma explants. Mol Cell Endocrinol 1996; 124:33-42. [PMID: 9027322 DOI: 10.1016/s0303-7207(96)03924-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We have previously shown that interleukin-2 (IL-2) and IL-6, which are expressed in the anterior pituitary, affect anterior pituitary cell proliferation in normal rats and cell lines. Here we examined their effects on the c-fos expression by human anterior pituitary adenomas. Adenoma cells in culture do not express c-fos mRNA. In adenoma explants, however, c-fos expression was detected and was regulated by IL-2 or IL-6. In different tumors (ACTH-, PRL-, GH-secreting and non functioning adenomas), these interleukins had inhibitory or stimulatory effects but the kind of response does not seem to be associated to tumor type or size. Using blocking antibodies, we observed that intrinsic IL-2 and IL-6 regulate c-fos expression in the same way. Our data suggest that IL-2 and IL-6 are not only involved in the regulation of pituitary adenoma function but may also, given the role of c-fos in cell proliferation, be implicated in the development of human pituitary adenomas.
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110
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Kovacs K, Scheithauer BW, Horvath E, Lloyd RV. The World Health Organization classification of adenohypophysial neoplasms. A proposed five-tier scheme. Cancer 1996; 78:502-10. [PMID: 8697397 DOI: 10.1002/(sici)1097-0142(19960801)78:3<502::aid-cncr18>3.0.co;2-2] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Although numerous attempts have been made, the classification of pituitary neoplasms remains controversial. METHODS The present proposal is based on correlative clinical and pathologic (histologic, immunocytochemical, and electron microscopic) studies of more than 8000 surgically removed human pituitary tumors. RESULTS Anterior pituitary tumors have been variously classified on the basis of their clinical presentation, biochemical findings, histology (growth pattern, tinctorial characteristics), proliferation indices, immunocytochemical profile, and ultrastructural features. Herein we propose a five-tier classification, clinicopathologic in nature, which focuses on endocrine activity, imaging, operative findings, histology, immunocytochemistry, and ultrastructure. The integration of these five complementary approaches into what is fundamentally a pathologic classification is as practical as it is novel. Its importance lies in the fact that the collected data provide valuable information to the clinical endocrinologist, neurosurgeon, and oncologist involved in the assessment of a tumor's biologic behavior, growth potential, therapeutic responsiveness, and prognosis. Due to financial restraints, lack of facilities, and unavailability of well trained personnel, we realize that at present the five approaches cannot be fully implemented in all institutions. Nonetheless, clinical and biochemical data, imaging, and operative findings, as well as basic histologic parameters are generally readily available. Collectively they are indispensable in establishing the correct diagnosis and in directing patient management. Conversely, the cost-effectiveness of immunocytochemistry and electron microscopy is debatable in that their performance and interpretation requires time, financial resources, and expertise. Nonetheless, it should be clear that any correlation between endocrine activity, growth potential, morphologic features, immunocytochemical profile, and ultrastructural features provides greater insight into the pathobiology of adenohypophysial tumors than is gained by routine histology alone. Thus we feel justified in including immunocytochemical and ultrastructural investigation of pituitary tumors in a modern classification. At present, more sophisticated molecular biologic methods represent investigative tools that play no significant role in the classification. CONCLUSIONS A five-tier classification of adenohypophysial neoplasms based on clinical and biochemical results, imaging, operative findings, histology, immunocytochemistry, and electron microscopy is proposed. It is recommended to the World Health Organization for acceptance.
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111
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Choo-Kang LR, Sun CC, Counts DR. Cholestasis and hypoglycemia: manifestations of congenital anterior hypopituitarism. J Clin Endocrinol Metab 1996; 81:2786-9. [PMID: 8768830 DOI: 10.1210/jcem.81.8.8768830] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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112
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Pearce SH, Trump D, Wooding C, Sheppard MN, Clayton RN, Thakker RV. Loss of heterozygosity studies at the retinoblastoma and breast cancer susceptibility (BRCA2) loci in pituitary, parathyroid, pancreatic and carcinoid tumours. Clin Endocrinol (Oxf) 1996; 45:195-200. [PMID: 8881452 DOI: 10.1046/j.1365-2265.1996.d01-1561.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Allelic deletion of the retinoblastoma (Rb) gene on chromosome 13 has been reported in both pituitary and parathyroid tumours. We have investigated the roles of the Rb and the hereditary breast cancer susceptibility gene (BRCA2), which lie within 25 cM of each other on chromosome 13q12-14, in the multi-step aetiology of endocrine tumours. PATIENTS AND MEASUREMENTS Seventy-seven endocrine tumours (43 anterior pituitary, 22 parathyroid, 7 carcinoid, and 5 pancreatic islet cell tumours) with paired leucocytes have been examined for loss of heterozygosity (LOH) at the Rb and BRCA2 loci by using specific oligonucleotide primers for the PCR amplification of microsatellite polymorphisms at three intragenic Rb markers, Rb1.20, Rbi4 and D13S153, and D13S260 which is linked to the BRCA2 locus. RESULTS Seventy-five of the 77 tumour-leucocyte pairs were informative and LOH was detected in 1 of 16 non-functioning pituitary tumours, 1 of 8 prolactinomas, 3 of 19 parathyroid adenomas and 1 of 1 parathyroid carcinoma. All the 3 parathyroid adenomas with LOH were associated with aggressive clinical and histopathological features. Allele loss was not detected in any of the 16 somatotrophinomas, 2 corticotrophinomas, 1 gonadotrophinoma, 7 carcinoid tumours (6 bronchial, 1 metastatic intestinal) or 5 pancreatic islet cell tumours that were informative. CONCLUSIONS These results demonstrate that allelic deletions of the 13q12-14 region occur in some pituitary adenomas and 16% of parathyroid adenomas. The extensive loss, which involves both the Rb gene and the BRCA2 locus, suggests that tumour suppressor genes in this region other than Rb or BRCA2 may be involved in the development and progression of some endocrine tumours.
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113
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Green VL, Atkin SL, Speirs V, Jeffreys RV, Landolt AM, Mathew B, Hipkin L, White MC. Cytokine expression in human anterior pituitary adenomas. Clin Endocrinol (Oxf) 1996; 45:179-85. [PMID: 8881450 DOI: 10.1046/j.1365-2265.1996.d01-1554.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE There is increasing evidence for the role of cytokines in pituitary differentiated function and tumorigenesis, but the spectrum of cytokines found in the pituitary is unknown. Therefore profiles of cytokine expression were determined in different human anterior pituitary adenoma sub-types. DESIGN The reverse transcriptase-linked polymerase chain reaction (PCR) was used to identify the presence of cytokine mRNA within human pituitary adenomas. PATIENTS Seventeen pituitary adenoma biopsies removed at transsphenoidal surgery were examined: 4 somatotrophinomas, 7 non-functional adenomas, 4 prolactinomas, one case of Cushing's disease and one case of Nelson's syndrome. MEASUREMENTS RNA was extracted from each adenoma biopsy and reverse transcribed into cDNA. This was specifically amplified in a PCR using oligonucleotide primers complementary to each cytokine. The cytokines investigated were interleukin (IL)-I alpha, IL-I beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, tumour necrosis factor (TNF)-alpha, TNF-beta and transforming growth factor (TGF)-beta 1, beta 2 and beta 3. The products of each PCR were visualized using agarose gel electrophoresis. RESULTS All 17 adenomas expressed IL-8 transcripts, but no expression of IL-2, IL-5 or IL-7 was found. IL-6 was expressed in all 4 somatotrophinomas, 3 of 7 non-functional tumours, 2 of 4 prolactinomas and in the single case of Nelson's syndrome. At least one of the 3 isoforms of TGF-beta was found in all but 2 tumours; one prolactinoma and one non-functional adenoma. IL-1 alpha, IL-beta, IL-4, TNF-alpha and TNF-beta were expressed sporadically by individual adenomas. CONCLUSION These data suggest that whilst IL-8 may be important, the local expression of the cytokines IL-2, IL-5 and IL-7 is not important in human anterior pituitary tumorigenesis.
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Hyde JF, Moore JP, Drake KW, Morrison DG. Galanin gene expression in radiothyroidectomy-induced thyrotroph adenomas. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 271:E24-30. [PMID: 8760077 DOI: 10.1152/ajpendo.1996.271.1.e24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Galanin gene expression is markedly increased in the anterior pituitary glands of estrogen-treated rats (lactotroph hyperplasia) as well as human growth hormone-releasing hormone transgenic mice (somatotroph hyperplasia). The objective of this study was to examine galanin in a mouse model of thyrotroph adenoma formation. Male mice were radiothyroidectomized by use of iodine-131 (131I), and galanin peptide levels were assessed in the hypothalamic-pituitary axis. Immunoreactive galanin concentrations in the anterior pituitaries of 131I-treated mice were decreased 80% at 3, 6, 9, and 12 mo after radiothyroidectomy. Galanin peptide levels in the hypothalamus were decreased 20-25% at these times. Treatment with either estradiol or 3,3',5-triiodo-L-thyronine increased galanin peptide concentrations in the anterior pituitaries of 131I-treated mice, but neither treatment restored galanin concentrations. Galanin mRNA levels were decreased > 80% 1 yr after radiothyroidectomy. We conclude that, unlike animal models of lactotroph and somatotroph hyperplasia, galanin gene expression is suppressed throughout the development of thyrotroph adenomas, suggesting that galanin does not have a stimulatory role in the proliferation of thyrotrophs. Moreover, these data show that thyroid hormones are important positive regulators of galanin gene expression in the mouse and that estrogen may stimulate galanin gene expression in the absence of thyroid hormones.
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115
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Virally-Monod ML, Barrou Z, Basin C, Thomopoulos P, Luton JP. [Lymphocytic hypophysitis: a reality]. Presse Med 1996; 25:933-8. [PMID: 8685157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Lymphocytic hypophysitis is a rare entity; we report here three cases. This condition usually occurs in women during pregnancy or in the post-partum period. Pituitary enlargement is associated with complete or partial hypopituitarism. The difficulty in diagnosis is well illustrated by our cases and results from the similarity between the clinical and biological signs of adenoma and hypophysitis. Circulating antipituitary antibodies are not constantly found and are nonspecific, evidence only of the autoimmune nature of hypophysitis. Thus the diagnosis has to be undertaken in all suspected cases in pregnant women or during the post-partum period. The clinical course may be very long, emphasizing the need for rigorous long-term observation. The pituitary gland is commonly enlarged and homogenous in lymphocytic hypophysitis, but in our third case the enlargement was heterogeneous with associated cyst formation. We suggest that the inflammatory process could have been maintained by the presence of cysts. Finally, corticosteroids are the therapy of choice in the inflammatory stage and should be undertaken as soon as the diagnosis has been established. Regular surveillance is required.
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116
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Cosserat J, Barete S, Baglin AC, Durepaire H, Bodiguel E, Gepner P, Piette AM, Blétry O, Barrier J. [Fever, partial pituitary insufficiency and interstitial lung syndrome in a 35-year-old woman]. Rev Med Interne 1996; 17 Suppl 2:241s-244s. [PMID: 8760669 DOI: 10.1016/0248-8663(96)86464-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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117
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Shipston MJ, Kelly JS, Antoni FA. Glucocorticoids block protein kinase A inhibition of calcium-activated potassium channels. J Biol Chem 1996; 271:9197-200. [PMID: 8621576 DOI: 10.1074/jbc.271.16.9197] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Adrenal corticosteroids have well known and profound effects on neurons and neuroendocrine cells, but the underlying cellular mechanisms are poorly understood. The present study analyzed membrane currents and ACTH release in AtT20 mouse pituitary corticotrope tumor cells. Patch-clamp analysis revealed a significant and selective inhibition of calcium-activated (BK-type) potassium channels upon activation of protein kinase A by corticotropin-releasing factor or 8-chlorophenylthio-cAMP. The synthetic glucocorticoid dexamethasone had no effect on potassium currents evoked by depolarization but prevented the inhibitory effect of protein kinase A activators. The action of dexamethasone had the hallmarks of protein induction, i.e. a lag time and sensitivity to inhibitors of DNA transcription and mRNA translation. In parallel, the specific BK channel blocker iberiotoxin abolished early glucocorticoid inhibition of corticotropin-releasing factor-stimulated ACTH secretion. In summary, the present data show that glucocorticoid-induced proteins render BK-type channels resistant to inhibition by protein kinase A and that this action of the steroid is pivotal for its early inhibitory effect on the secretion of ACTH.
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118
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Antoni FA, Barnard RJ, Shipston MJ, Smith SM, Simpson J, Paterson JM. Calcineurin feedback inhibition of agonist-evoked cAMP formation. J Biol Chem 1995; 270:28055-61. [PMID: 7499291 DOI: 10.1074/jbc.270.47.28055] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The effects of immunosuppressant blockers of calcineurin (protein phosphatase 2B) on cAMP formation and hormone release were investigated in mouse pituitary tumor (AtT20) cells. Immunosuppressants enhanced corticotropin-releasing factor- and isoproterenol-evoked cAMP production in proportion with their potency to block calcineurin. Further analysis of cAMP production revealed that intracellular Ca2+ derived through voltage-regulated calcium channels reduces cAMP formation induced by corticotropin releasing-factor or beta 2-adrenergic stimulation and that this effect of Ca2+ is inhibited by blockers of calcineurin. AtT20 cells were found to express at least three species of adenylyl cyclase mRNA-encoding types 1 and 6 as well as a novel isotype, which appeared to be the predominant species. In two cell lines expressing very low or undetectable levels of the novel cyclase mRNA (NCB20 and HEK293 cells respectively), corticotropin-releasing factor-induced cAMP formation was not altered upon blockage of calcineurin activity. These data identify calcineurin as a Ca2+ sensor that mediates the negative feedback effect of intracellular Ca2+ on receptor-stimulated cAMP production. Furthermore, the effect of calcineurin on cAMP synthesis appears to be associated with the expression of a novel adenylyl cyclase isotype, which is highly abundant in AtT20 cells.
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119
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Kaufmann P, Lax SF, Radner H, Eber B, Leuger A, Smolle KH. Severe hypotension and coma secondary to unrecognized chronic anterior hypophysitis. Intensive Care Med 1995; 21:847-9. [PMID: 8557875 DOI: 10.1007/bf01700970] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We report an endocrine emergency of a 52-year-old woman with chronic anterior-pituitary failure of autoimmune origin who developed hypopituitary crisis with coma and severe hypotension provoked by an intercurrent bronchopneumonia. At admission to the ICU hypopituitarism had not been diagnosed and only Hashimoto's thyroiditis with thyroid replacement therapy could be obtained from the patient's history. Although the patient presented with somatic signs suggestive of hypopituitarism, other causes of coma and hypotension had first to be excluded. In the absence of specific treatment the patient died 18 h later with refractory cardiac arrest. Diagnosis of acute decompensated chronic hypophyseal failure must be considered if hypothermia, refractory hypotension and signs of infection without fever are associated with a short stature and the loss of axillary and public hair. Waiting for laboratory confirmation of the diagnosis must not delay immediate life-saving specific glucocorticoid treatment.
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120
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Iwase T, Nishizawa S, Baba S, Hinokuma K, Sugimura H, Nakamura S, Uemura K, Shirasawa H, Kino I. Intrasellar neuronal choristoma associated with growth hormone-producing pituitary adenoma containing amyloid deposits. Hum Pathol 1995; 26:925-8. [PMID: 7635456 DOI: 10.1016/0046-8177(95)90018-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The histological, immunocytochemical, and ultrastructural features of an intrasellar neuronal choristoma associated with pituitary growth hormone (GH)-producing adenoma are reported. Immunohistochemistry studies and electron microscopy examination showed the adenoma cells to be positive for GH but negative for prolactin, and the neurons of the choristoma to have GH-releasing factor (GRF) neurosecretory activity. The adenoma also had many amyloid deposits in its extracellular space immunoreactive to GRF. This is the first report of the tumor containing amyloid deposits.
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121
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Fujino S, Kato T, Dazai Y, Iwata T, Hiwada K, Kawabe T. [Case of Cushing's syndrome associated with empty sella syndrome and anterior pituitary hypofunction]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 1995; 84:619-21. [PMID: 7636360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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122
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Pressman EK, Zeidman SM, Reddy UM, Epstein JI, Brem H. Differentiating lymphocytic adenohypophysitis from pituitary adenoma in the peripartum patient. THE JOURNAL OF REPRODUCTIVE MEDICINE 1995; 40:251-9. [PMID: 7623353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Lymphocytic adenohypophysitis (LAH) is an autoimmune disorder of the pituitary gland with a predilection for the peripartum period and often mimics a pituitary adenoma. We sought to define the clinical, endocrinologic and radiographic characteristics differentiating peripartum LAH from pituitary adenoma to enable the use of noninvasive diagnosis and appropriate therapy. From published reports and our own case, the clinical histories and laboratory and radiographic studies of 45 patients fulfilling the diagnosis of peripartum LAH were reviewed. History of infertility or menstrual irregularity, symptomatology, endocrinologic evaluation, diagnostic imaging and associated medical conditions were analyzed. For comparison, 806 patients with pituitary adenoma and pregnancy from published series were evaluated. The spontaneous pregnancy rate in pituitary adenoma patients was 2.4% vs. 100% in LAH patients. Visual disturbances and headaches were significantly more frequent in patients with LAH. Prolactin levels were significantly lower in patients with LAH than in those with pituitary adenomas (34.6 +/- 46.3 [SD] vs. 393.0 +/- 300.4, P < .0001). Abnormalities in thyroid and/or adrenal function were also more common in patients with LAH (57.5% vs. 2.5%, P < .001). There were no distinguishing characteristics on radiographic studies. History and endocrinologic evaluation can differentiate between LAH and pituitary adenoma in the peripartum patient.
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123
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Prager D, Braunstein GD. Pituitary disorders during pregnancy. Endocrinol Metab Clin North Am 1995; 24:1-14. [PMID: 7781620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A number of morphologic and physiologic changes accompany pregnancy such as an increase in lactotrophs and prolactin production, and a decrease in gonadotropins and GH. The hormonal milieu can affect patients with prolactinomas, especially macroadenomas, to cause an increase in size in a minority of patients. Complications are treated with bromocryptine. Enlargement of GH-secreting tumors with acromegaly may respond to bromocryptine and possibly to octreotide. Pituitary tumors causing Cushing's syndrome may need removal if major complications develop. Hypopituitarism during pregnancy may be the result of lymphocytic hypophysitis or antepartum pituitary necrosis, and in the postpartum period may be because of postpartum hemorrhage and pituitary necrosis. These abnormalities need prompt recognition and hormonal replacement therapy with neurosurgical decompression to avoid serious morbidity and mortality. Posterior pituitary problems in pregnancy usually manifest by diabetes insipidus, with a pregnancy-specific variety resulting from excessive degradation of AVP by placental vasopressinase. The condition is treated with an analogue dDAVP, which is resistant to vasopressinase.
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Simmer HH. [Not Available]. MEDIZINHISTORISCHES JOURNAL 1995; 30:167-183. [PMID: 11634254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Elgort A, Shields D. Prosomatostatin processing in pituitary GH3 cells. Identification and secretion of the intact propeptide. J Biol Chem 1994; 269:30668-75. [PMID: 7982986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Preprosomatostatin (preproSRIF) is a peptide hormone precursor that undergoes tissue-specific processing at either a single set of paired basic residues to yield SRIF-14 or, alternatively, at a monobasic site to produce SRIF-28, an NH2 terminally extended form of SRIF-14. Mammalian preproSRIFs are a family of precursors that are remarkably conserved from rat to humans. In five species, the signal peptide and propeptides are approximately 96% identical; this high degree of sequence identity may be indicative of functional conservation. Since the propeptide is approximately five times larger than SRIF-14, we hypothesized that it would be secreted as a separate polypeptide following proSRIF proteolytic processing. To test this idea, we raised polyclonal antibodies to the entire propeptide to follow its biosynthesis and secretion. Here we demonstrate that in transfected rat anterior pituitary GH3 cells both SRIF-14 and the intact 9.5-kDa propeptide were processed coordinately from proSRIF with identical kinetics. Treatment of the cells with chloroquine, a weak base which inhibits processing to mature SRIF-14, also inhibited the appearance of the 9.5-kDa propeptide. Approximately 40% of the propeptide was targeted to the regulated secretory pathway as determined by its quantitative secretion in response to secretagogues. We also examined the secretion of the SRIF propeptide independently of SRIF-14 by expressing a truncated "propeptide" in which SRIF-14 was deleted. Significantly, the SRIF propeptide was itself efficiently transported through the secretory pathway and secreted into the culture medium. This suggests that the propeptide possesses all the topogenic information necessary for intracellular transport. The coordinate secretion of the intact propeptide with mature SRIF-14 suggests that it might function as a novel bioactive peptide.
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