A Human β-Endorphin Pituitary Adenoma

Trouillas, J.; Girod, C; Sassolas, G.; Vitte, Pierre-Alain; Bruno, Claudio; Perrin, G; Lhéritier, M.; Fischer, Claudia; Dubois, M. P.

doi:10.1210/jcem-58-2-242

Cited by 28 publications

(4 citation statements)

References 21 publications

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“…When this action is blocked by naltrexone, PC1/3 and PC2 levels increase. It would be interesting if animals with low β-endorphin levels [such as those with targeted truncation of the POMC gene leading to absent β-endorphin [38] or patients with excess β-endorphin [48] would have altered PC1/3 and PC2 expression.…”

Section: Discussionmentioning

confidence: 99%

Morphine treatment selectively regulates expression of rat pituitary POMC and the prohormone convertases PC1/3 and PC2

et al. 2013

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The prohormone convertases, PC1/3 and PC2 are thought to be responsible for the activation of many prohormones through processing including the endogenous opioid peptides. We propose that maintenance of hormonal homeostasis can be achieved, in part, via alterations in levels of these enzymes that control the ratio of active hormone to prohormone. In order to test the hypothesis that exogenous opioids regulate the endogenous opioid system and the enzymes responsible for their biosynthesis, we studied the effect of short-term morphine or naltrexone treatment on pituitary PC1/3 and PC2 as well as on the level of pro-opiomelanocortin (POMC), the precursor gene for the biosynthesis of the endogenous opioid peptide, beta-endorphin. Using ribonuclease protection assays, we observed that morphine down-regulated and naltrexone up-regulated rat pituitary PC1/3 and PC2 mRNA. Immunofluorescence and Western blot analysis confirmed that the protein levels changed in parallel with the changes in mRNA levels and were accompanied by changes in the levels of phosphorylated cyclic-AMP response element binding protein. We propose that the alterations of the prohormone processing system may be a compensatory mechanism in response to an exogenous opioid ligand whereby the organism tries to restore its homeostatic hormonal milieu following exposure to the opioid, possibly by regulating the levels of multiple endogenous opioid peptides and other neuropeptides in concert.

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Section: Discussionmentioning

confidence: 99%

Morphine treatment selectively regulates expression of rat pituitary POMC and the prohormone convertases PC1/3 and PC2

et al. 2013

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“…Several authors have postulated production of small amounts of hormone, abnormal hormone, or other substances (Horvath et al, 1980;Hassoun et al, 1982;Reincke et al, 1987;Trouillas et al, 1984). The possibility that p-endorphin is the main hormonal product of this tumor type is supported by the striking association of hyperprolactinemia with even small tumors in which the hormone excess cannot be attributed to "stalk section effect" (Horvath et al, 1980;Trouillas et al, 1984). Lysosomal accumulation with crinophagy has been described in a single case (Kovacs et al, 19781, suggest-ing a defect in the release of secretory granules and their intracellular lysosomal disposal.…”

Section: Results and Discussion Nontumorous Pituitariesmentioning

confidence: 99%

Utilization of electron microscopic techniques in the in vitro study of adenohypophysial function and regulation

Sylvia

Kovács

1992

Microscopy Res & Technique

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Morphologic studies of human adenohypophysial cells using immunocytochemistry and electron microscopy have characterized the hormone-producing cell types of the normal gland and pituitary adenomas. The classifications which have emerged allow more accurate clinicopathologic correlations than ever before, but have also raised new questions concerning cytogenesis, pathogenesis, and structure-function correlations. We report the results of studies which marry the conventional morphologic techniques of light microscopy, immunohistochemistry, electron microscopy, and ultrastructural immunocytology with functional analyses using tissue culture and radioimmunoassay of hormones released into culture media. The hormone secretory activity of nontumorous and adenomatous pituitary cells is correlated with their structural features; their secretory responses to several adenohypophysiotropic factors are compared with morphologic alterations which are characterized at the light and electron microscopic levels by morphometric analysis. These studies have shown that hypothalamic stimulating hormones increase hormone release by their target cells and alter the ultrastructural appearance of the affected cells by increasing organelles involved in hormone synthesis. Inhibitory drugs and adrenal and gonadal steroids are capable of suppressing hormone release by some tumors and also give rise to morphologic changes which correlate with the functional inhibition. Hormone release by clinically nonfunctioning adenomas has been characterized and the behavior of these tumor cells in vitro sheds some light on the reasons for lack of clinical symptomatology. The plurihormonal nature of several nontumorous and adenomatous pituitary cell types has been characterized in vitro. The results of these studies provide the basis for more accurate structure-function correlations which can be used to study the hormonal milieu in vivo, to predict the role of pathogenetic factors in pituitary tumorigenesis, and to assess the therapeutic value of stimulating or inhibiting hormones and drugs.

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“…Beta-END was observed in a pituitary adenoma [266], and the peptide was released from human pituitary cancer cells [267]. The presence of beta-END has been reported in clinically silent pituitary corticotroph adenomas [268], and beta-END and beta-END 1-27 have been found in extracts of pituitary melanotroph tumors transplanted subcutaneously in mice [269].…”

Section: Endorphinmentioning

confidence: 96%

Involvement of the Opioid Peptide Family in Cancer Progression

2023

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Peptides mediate cancer progression favoring the mitogenesis, migration, and invasion of tumor cells, promoting metastasis and anti-apoptotic mechanisms, and facilitating angiogenesis/lymphangiogenesis. Tumor cells overexpress peptide receptors, crucial targets for developing specific treatments against cancer cells using peptide receptor antagonists and promoting apoptosis in tumor cells. Opioids exert an antitumoral effect, whereas others promote tumor growth and metastasis. This review updates the findings regarding the involvement of opioid peptides (enkephalins, endorphins, and dynorphins) in cancer development. Anticancer therapeutic strategies targeting the opioid peptidergic system and the main research lines to be developed regarding the topic reviewed are suggested. There is much to investigate about opioid peptides and cancer: basic information is scarce, incomplete, or absent in many tumors. This knowledge is crucial since promising anticancer strategies could be developed alone or in combination therapies with chemotherapy/radiotherapy.

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A Human β-Endorphin Pituitary Adenoma

Cited by 28 publications

References 21 publications

Morphine treatment selectively regulates expression of rat pituitary POMC and the prohormone convertases PC1/3 and PC2

Morphine treatment selectively regulates expression of rat pituitary POMC and the prohormone convertases PC1/3 and PC2

Utilization of electron microscopic techniques in the in vitro study of adenohypophysial function and regulation

Involvement of the Opioid Peptide Family in Cancer Progression

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