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Orphanet Journal of Rare Diseases Oct 2016Secreting pituitary adenomas that cause acromegaly and Cushing's disease, as well as prolactinomas and thyrotroph adenomas, are uncommon, usually benign, slow-growing... (Review)
Review
Secreting pituitary adenomas that cause acromegaly and Cushing's disease, as well as prolactinomas and thyrotroph adenomas, are uncommon, usually benign, slow-growing tumours. The rarity of these conditions means that their diagnosis is not familiar to most non-specialist physicians. Consequently, pituitary adenomas may be overlooked and remain untreated, and affected individuals may develop serious comorbidities that reduce their quality of life and life expectancy. Because many signs and symptoms of pituitary adenomas overlap with those of other, more common disorders, general practitioners and non-endocrinology specialists need to be aware of the "red flags" suggestive of these conditions. A long duration of active disease in patients with secreting pituitary adenomas is associated with an increased risk of comorbidities and reduced quality of life. Appropriate treatment can lead to disease remission, and, although some symptoms may persist in some patients, treatment usually reduces the incidence and severity of comorbidities and improves quality of life. Therefore, correct, early diagnosis and characterization of a pituitary adenoma is crucial for patients, to trigger timely, appropriate treatment and to optimize outcome. This article provides an overview of the epidemiology of hormonal syndromes associated with pituitary adenomas, discusses the difficulties of and considerations for their diagnosis, and reviews the comorbidities that may develop, but can be prevented, by accurate diagnosis and appropriate treatment. We hope this review will help general practitioners and non-endocrinology specialists to suspect secreting pituitary adenomas and refer patients to an endocrinologist for confirmation of the diagnosis and treatment.
Topics: Acromegaly; Adenoma; Female; Humans; Male; Pituitary ACTH Hypersecretion; Pituitary Neoplasms; Prolactinoma; Quality of Life
PubMed: 27716353
DOI: 10.1186/s13023-016-0516-x -
Cell Death & Disease Apr 2019The treatment of hyperprolactinemia is based on the use of dopamine agonists, mainly bromocriptine (BRC) and cabergoline (CAB). They reduce tumour size effectively and...
The treatment of hyperprolactinemia is based on the use of dopamine agonists, mainly bromocriptine (BRC) and cabergoline (CAB). They reduce tumour size effectively and restore gonadal function. However, there is a difference in drug sensitivity between CAB and BRC in patients with prolactinoma, although the underlying mechanisms are still unknown. Thus, we investigated whether there are differences in tumour sensitivity to CAB and BRC and their possible differential mechanisms in two prolactinoma cell lines. In our study, we found that GH3 cells are more sensitive to BRC and that MMQ cells are more sensitive to CAB. Moreover, BRC and CAB elicited cell death via different pathways; BRC induced prolactinoma cell death mainly through the apoptosis pathway, and CAB induced pituitary prolactinoma cell death mainly via the autophagic cell death pathway. Using gene microarray analysis, we found that BRC induces the apoptosis of prolactinoma cells through the ERK/EGR1 signalling pathway, whereas CAB induces autophagic death by inhibiting the AKT/mTOR signalling pathway. Our study showed the difference in tumour sensitivity and differential mechanisms in BRC- and CAB-treated prolactinoma cells, which provides a theoretical basis for the accurate treatment of prolactinoma.
Topics: Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Bromocriptine; Cabergoline; Cell Line, Tumor; Early Growth Response Protein 1; Extracellular Signal-Regulated MAP Kinases; Female; Mice; Mice, Nude; Microtubule-Associated Proteins; Pituitary Neoplasms; Prolactinoma; Proto-Oncogene Proteins c-akt; RNA Interference; RNA, Small Interfering; Rats; Signal Transduction; TOR Serine-Threonine Kinases
PubMed: 31000722
DOI: 10.1038/s41419-019-1526-0 -
The Journal of Clinical Endocrinology... Sep 2015Coexisting prolactinoma-primary aldosteronism (PA) is infrequently reported.
CONTEXT
Coexisting prolactinoma-primary aldosteronism (PA) is infrequently reported.
OBJECTIVE
The objective of the study was to identify patients with prolactinoma-PA and test the hypothesis that elevated prolactin (PRL) concentrations play a role in PA pathogenesis.
SETTING AND DESIGN
Hyperprolactinemia/prolactinoma was diagnosed in PA patients from two referral centers (Munich, Germany, and Turin, Italy) and in essential hypertensive (EH) patients from one center (Turin). PRL receptor (PRLR) gene expression was determined by microarrays on aldosterone-producing adenomas and normal adrenals and validated by real-time PCR. H295R adrenal cells were incubated with 100 nM PRL, and gene expression levels were determined by real-time PCR and aldosterone production was quantified.
RESULTS
Seven patients with prolactinoma-PA were identified: four of 584 and three of 442 patients from the Munich and Turin PA cohorts, respectively. A disproportionate number presented with macroprolactinomas (five of seven). There were five cases of hyperprolactinemia with no cases of macroprolactinoma of 14 790 patients in a general EH cohort. In a population of PA patients case-control matched 1:3 with EH patients there were two cases of hyperprolactinemia of 270 PA patients and no cases in the EH cohort (n = 810). PRLR gene expression was significantly up-regulated in the aldosterone-producing adenomas compared with normal adrenals (1.7-fold and 1.5-fold by microarray and real-time PCR, respectively). In H295R cells, PRL treatment resulted in 1.3-fold increases in CYP11B2 expression and aldosterone production.
CONCLUSION
Elevated PRL caused by systemic hyperprolactinemia may contribute to the development of PA in those cases in which the two entities coexist.
Topics: Adult; Cell Line, Tumor; Female; Humans; Hyperaldosteronism; Male; Middle Aged; Pituitary Neoplasms; Prolactin; Prolactinoma; Receptors, Prolactin
PubMed: 26176803
DOI: 10.1210/JC.2015-2422 -
Endocrinology Jun 2018Prolactin-secreting adenomas, or prolactinomas, cause hypogonadism, osteoporosis, and infertility. Although dopamine agonists (DAs) are used clinically to treat...
Prolactin-secreting adenomas, or prolactinomas, cause hypogonadism, osteoporosis, and infertility. Although dopamine agonists (DAs) are used clinically to treat prolactinoma and reduce prolactin secretion via cAMP inhibition, the precise mechanism by which DAs inhibit lactotrope proliferation has not been defined. In this study, we report that phosphatidylinositol 3-kinase (PI3K) signals through AKT and mTOR to drive proliferation of pituitary somatolactotrope GH4T2 cells. We demonstrate that the DA cabergoline reduces activity of the mTOR effector s6K and diminishes GH4T2 cell proliferation primarily via activation of the long isoform of the dopamine D2 receptor (D2R). Dysfunctional D2R-mediated signaling and/or downregulated D2R expression is thought be the primary mechanism of DA resistance, which is observed in 10% to 20% of prolactinoma tumors. Dopamine-mediated D2R activation results in ERK stimulation and PI3K inhibition, suggesting that these two pathways act in an inverse manner to maintain lactotrope homeostasis. In this study, we found that ERK1/2-mediated prolactin transcription is inhibited by PI3K/CDK4-driven cell cycle progression, emphasizing that the ERK and PI3K signaling pathways oppose one another in lactotrope cells under homeostatic conditions. Lastly, we show that both ERK1/2 and AKT are activated in prolactinoma, demonstrating that the balance of ERK and AKT is dysregulated in human prolactinoma. Our findings reveal a potential use for dual pharmacological inhibitors of ERK and AKT as an alternative treatment strategy for DA-resistant prolactinomas.
Topics: Animals; Cabergoline; Cell Proliferation; Cells, Cultured; Dopamine; Down-Regulation; HEK293 Cells; Homeostasis; Humans; MAP Kinase Signaling System; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Pituitary Neoplasms; Prolactinoma; Rats; Signal Transduction
PubMed: 29726995
DOI: 10.1210/en.2017-03135 -
Pituitary Feb 2020Consensus guidelines recommend dopamine agonists (DAs) as the mainstay treatment for prolactinomas. In most patients, DAs achieve tumor shrinkage and normoprolactinemia... (Review)
Review
Consensus guidelines recommend dopamine agonists (DAs) as the mainstay treatment for prolactinomas. In most patients, DAs achieve tumor shrinkage and normoprolactinemia at well tolerated doses. However, primary or, less often, secondary resistance to DAs may be also encountered representing challenging clinical scenarios. This is particularly true for aggressive prolactinomas in which surgery and radiotherapy may not achieve tumor control. In these cases, alternative medical treatments have been considered but data on their efficacy should be interpreted within the constraints of publication bias and of lack of relevant clinical trials. The limited reports on somatostatin analogues have shown conflicting results, but cases with optimal outcomes have been documented. Data on estrogen modulators and metformin are scarce and their usefulness remains to be evaluated. In many aggressive lactotroph tumors, temozolomide has demonstrated optimal outcomes, whereas for other cytotoxic agents, tyrosine kinase inhibitors and for inhibitors of mammalian target of rapamycin (mTOR), higher quality evidence is needed. Finally, promising preliminary results from in vitro and animal reports need to be further assessed and, if appropriate, translated in human studies.
Topics: Cabergoline; Dopamine Agonists; Female; Humans; Male; Prolactinoma
PubMed: 31522358
DOI: 10.1007/s11102-019-00987-3 -
BMC Endocrine Disorders Nov 2021Prolactinoma is the major cause of hyperprolactinemia, and dopamine agonists (DAs) are generally the first-line treatment for them. Several studies have reviewed the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Prolactinoma is the major cause of hyperprolactinemia, and dopamine agonists (DAs) are generally the first-line treatment for them. Several studies have reviewed the recurrent rate of hyperprolactinemia after DAs withdrawal. However, few of them have concerned the recurrence risk of prolactinoma following the withdrawal of DAs.
METHODS
Three medical databases, PubMed, EMBASE and Cochrane library, were retrieved up to February, 14, 2021 to identify studies related to recurrence of prolactinoma and withdrawal of DAs. Statistical analyses including meta-analysis, sensitivity analysis, meta-regression, funnel plot and Egger test were performed through software R.
RESULTS
A total of 3225 studies were retrieved from the three data bases, and 13 studies consisted of 616 patients and 19 arms were finally included in this systematic analysis. There was no significant heterogeneity among the included studies, and fixed effect model was thus used. The pooled recurrence proportion of prolactinoma after withdrawal of DA was 2% with a 95% confidence interval (CI) of 1-3%.
CONCLUSION
Our study showed a very low recurrent rate of prolactinomas after DAs withdrawal. Much more prospective studies with larger cases and longer follow-up period are encouraged to confirm our finding.
TRIAL REGISTRATION
Registration number CRD42021245888 (PROSPERO).
Topics: Bromocriptine; Cabergoline; Deprescriptions; Dopamine Agonists; Humans; Neoplasm Recurrence, Local; Pituitary Neoplasms; Prolactinoma
PubMed: 34774043
DOI: 10.1186/s12902-021-00889-1 -
Neuroendocrinology 2016Pituitary adenomas are a common feature of a subset of endocrine neoplasia syndromes, which have otherwise highly variable disease manifestations. We provide here a... (Review)
Review
Pituitary adenomas are a common feature of a subset of endocrine neoplasia syndromes, which have otherwise highly variable disease manifestations. We provide here a review of the clinical features and human molecular genetics of multiple endocrine neoplasia (MEN) type 1 and 4 (MEN1 and MEN4, respectively) and Carney complex (CNC). MEN1, MEN4, and CNC are hereditary autosomal dominant syndromes that can present with pituitary adenomas. MEN1 is caused by inactivating mutations in the MEN1 gene, whose product menin is involved in multiple intracellular pathways contributing to transcriptional control and cell proliferation. MEN1 clinical features include primary hyperparathyroidism, pancreatic neuroendocrine tumours and prolactinomas as well as other pituitary adenomas. A subset of patients with pituitary adenomas and other MEN1 features have mutations in the CDKN1B gene; their disease has been called MEN4. Inactivating mutations in the type 1α regulatory subunit of protein kinase A (PKA; the PRKAR1A gene), that lead to dysregulation and activation of the PKA pathway, are the main genetic cause of CNC, which is clinically characterised by primary pigmented nodular adrenocortical disease, spotty skin pigmentation (lentigines), cardiac and other myxomas and acromegaly due to somatotropinomas or somatotrope hyperplasia.
Topics: Acromegaly; Animals; Carney Complex; Endocrine Gland Neoplasms; Humans; Multiple Endocrine Neoplasia; Pituitary Neoplasms; Prolactinoma
PubMed: 25592387
DOI: 10.1159/000371819 -
International Journal of Molecular... Nov 2017The pituitary gland is part of hypothalamic-pituitary-gonadal axis, which controls development, reproduction, and aging in humans and animals. In addition, the pituitary... (Review)
Review
The pituitary gland is part of hypothalamic-pituitary-gonadal axis, which controls development, reproduction, and aging in humans and animals. In addition, the pituitary gland is regulated mainly by hormones and neurotransmitters released from the hypothalamus and by systemic hormones secreted by target glands. Aromatase P450, the enzyme responsible for the catabolization of aromatizable androgens to estrogens, is expressed in different parts of body, including the pituitary gland. Moreover, aromatase P450 is involved in sexual dimorphism where alteration in the level of aromatase can initiate a number of diseases in both genders. On the other hand, the direct actions of estrogens, mainly estradiol, are well known for stimulating prolactin release. Numerous studies have shown that changes in the levels of estrogens, among other factors, have been implicated in the genesis and development of prolactinoma. The pituitary gland can produce estradiol locally in several types of endocrine cells, and it is possible that aromatase could be responsible for the maintenance of the population of lactotroph cells and the modulation of the action of central or peripheral regulators. Aromatase overexpression due to inappropriate gene regulation has clinical effects such as the pathogenesis of prolactinomas. The present study reports on the synthesis of pituitary aromatase, its regulation by gonadal steroids, and the physiological roles of aromatase on pituitary endocrine cells. The involvement of aromatase in the pathogenesis of pituitary tumors, mainly prolactinomas, through the auto-paracrine production of estradiol is reviewed.
Topics: Animals; Apoptosis; Aromatase; Cell Proliferation; Estrogens; Humans; Pituitary Gland; Pituitary Neoplasms; Prolactin; Prolactinoma
PubMed: 29104246
DOI: 10.3390/ijms18112299 -
Neuroendocrinology 2019The behaviour of lactotroph tumours varies between benign tumours, those cured by treatment, and that of aggressive tumours, and carcinomas with metastasis.... (Review)
Review
The behaviour of lactotroph tumours varies between benign tumours, those cured by treatment, and that of aggressive tumours, and carcinomas with metastasis. Identification of clinical, pathological and molecular factors is essential for the early identification of patients that may have such aggressive tumours. Plasma prolactin levels and tumour size and invasion, per se, are not prognostic factors. However, tumours appearing at a young age (<20 years), especially in boys, and the presence of genetic predisposition have a poorer prognosis. In addition, lactotroph tumours in men differ from those in women, being larger, more often invasive, and resistant to dopamine agonists. They are also more often high-grade with a high risk of recurrence and malignancy. The expression of estrogen receptor α is lower than in women and is closely correlated to aggressiveness. Proliferation markers (Ki-67 expression: ≥3%, mitotic count n > 2) are correlated to invasion and proliferation, but, taken alone, their prognostic value is debatable. Based on a 5-tiered clinicopathological classification, and taking into account invasion and proliferation, a grade 2b (aggressive) lactotroph tumour has a 20× risk of progression compared to a grade 1a (benign) tumour. Moreover, lactotroph tumours are the second-most frequent aggressive and malignant tumour. Other factors, such as the expression of growth factors (vascular endothelial growth factor [VEGF] and epidermal growth factor [EGF]), the genes regulating invasion, differentiation and proliferation, adhesion molecules (E-cadherin), matrix metalloproteinase 9, and chromosome abnormalities (chromosomes 11, 19, and 1), have also been correlated with aggressiveness. Currently, clinical signs, a prognostic classification, and molecular and genetic markers may all help the clinician in the early identification of aggressive lactotroph tumours and enable stratification of their management.
Topics: Female; Humans; Male; Pituitary Neoplasms; Prolactinoma
PubMed: 30943495
DOI: 10.1159/000499382 -
Endocrinology Feb 2021Prolactin production is controlled by a complex and temporally dynamic network of factors. Despite this tightly coordinated system, pathological hyperprolactinemia is a...
Prolactin production is controlled by a complex and temporally dynamic network of factors. Despite this tightly coordinated system, pathological hyperprolactinemia is a common endocrine disorder that is often not understood, thereby highlighting the need to expand our molecular understanding of lactotroph cell regulation. MicroRNA-7 (miR-7) is the most highly expressed miRNA family in the pituitary gland and the loss of the miR-7 family member, miR-7a2, is sufficient to reduce prolactin gene expression in mice. Here, we used conditional loss-of-function and gain-of-function mouse models to characterize the function of miR-7a2 in lactotroph cells. We found that pituitary miR-7a2 expression undergoes developmental and sex hormone-dependent regulation. Unexpectedly, the loss of mir-7a2 induces a premature increase in prolactin expression and lactotroph abundance during embryonic development, followed by a gradual loss of prolactin into adulthood. On the other hand, lactotroph development is delayed in mice overexpressing miR-7a2. This regulation of lactotroph function by miR-7a2 involves complementary mechanisms in multiple cell populations. In mouse pituitary and rat prolactinoma cells, miR-7a2 represses its target Raf1, which promotes prolactin gene expression. These findings shed light on the complex regulation of prolactin production and may have implications for the physiological and pathological mechanisms underlying hyperprolactinemia.
Topics: Animals; Cell Line; Estradiol; Female; Fertility; Lactation; Lactotrophs; Male; Mice; MicroRNAs; Pituitary Neoplasms; Prolactin; Prolactinoma; Proto-Oncogene Proteins c-raf; Sex Characteristics
PubMed: 33248443
DOI: 10.1210/endocr/bqaa220