Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cDNA membrane array displaying 1183 probes was used to detect hypothalamic and pituitary changes in gene expression accompanying ageing and age-associated pituitary macroadenomas. Four groups of male Sprague-Dawley rats (3-, 15-, 24-month-old and 24-month-old with prolactinoma) were compared in two independent hybridizations. cDNA array data were confirmed and completed by comparative reverse transcriptase-polymerase chain reaction on selected genes. The expression of 454 and 116 mRNAs was detected in hypothalamus and pituitary, respectively. Growth hormone (GH) mRNA alone represented 85% of total gene expression in the gland of young rats, and other pituitary hormone transcripts 2.8%, while melanin-concentrating hormone (MCH) mRNA, the most expressed neuropeptide transcript involved in neuroendocrine regulation, accounted for only 0.8% of total hypothalamic transcripts. The proportion of genes modified in the hypothalamus and pituitary was rather modest: 1.5% and 5.2%, respectively, for ageing per se, and 1.1% and 5.2% for age-associated macroprolactinomas. Among pituitary specific RNAs, GH mRNA expression was notably decreased with age. At the hypothalamic level, expression of genes directly involved in GH regulation, such as somatostatin and growth hormone-releasing hormone, was not altered, while neuropeptide transcripts involved in feeding behaviour [orexin/hypocretin, MCH, pro-opiomelanocortin (POMC), cocaine- and amphetamine-regulated transcript (CART)] were significantly altered. In addition, a few ubiquitous transcripts (hnRNP-K, PFKm, CCND 2, calponin and set) were differently affected in both tissues. Modifications in hypothalamic orexigenic (orexin, MCH) and anorexigenic (POMC, CART) gene expression are in keeping with an age-associated decrease in energy consumption but a higher one in the presence of macroprolactinomas.
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PMID:Age-associated changes in hypothalamic and pituitary neuroendocrine gene expression in the rat. 1271 10

In recent years, the medical therapy for prolactinomas and GH-secreting adenomas has greatly improved due to the availability of new, highly effective, long-acting dopamine and somatostatin analogues. Although medical therapy has for some time been the first-line approach to prolactinoma management, the incidence of patients requiring surgery for resistance or intolerance/noncompliance is likely to decrease substantially with these new agents. Increasing efficacy and greater ease of administration of somatostatin analogues for GH, and for rare TSH, adenomas are also anticipated to lead to less reliance on surgery and radiation therapy as the primary therapy in these disorders. Although somewhat unclear at this time, GH antagonists hold promise for alternative or adjunct therapy for acromegaly. Given the significant morbidity and mortality associated with acromegaly, these advances are quite encouraging. Unfortunately, little if any progress has been made toward establishing an effective medical treatment for gonadotropin or nonsecreting tumors. However, new approaches to delivery of radiation therapy may reduce some of the inconvenience and risk of this treatment for patients when surgery alone is inadequate. In all of these disorders, the challenge to physicians and their patients remains one of choosing a rational combination of medical, surgical, and radiation therapy. Fortunately, for most patients, control, if not cure, of their pituitary adenoma is a reasonable expectation.
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PMID:Diagnosis and management of pituitary tumors: recent advances. 1502 95

It is well established that disruption of apoptosis may lead to tumor initiation, progression or metastasis. It is also well documented that many anticancer drugs induce apoptosis. In the earlier studies, the dopamine D2 receptor agonist bromocriptine (BC) and somatostatin analog octreotide (OCT) were found to inhibit the growth of the estrogen-induced rat prolactinoma. Our previous investigations, applying the TUNEL method showed the involvement of the pro-apoptotic effect in the action of BC, and to a lesser degree, in the action of OCT. The aim of the present study was to investigate whether the pro-apoptotic action of these drugs involves the increased expression of Bax--a member of Bcl-2 protein family which is known to play an important role in the regulation of apoptosis. Male four-week Fisher 344 rats were used in the experiment. Capsules containing diethylstilboestrol (DES) were implanted subcutaneously. Six weeks after the implantation the rats were given OCT (2 x 25 microg/animal/24), BC (3 mg/kg b.w./24 h) or OCT and BC at the above doses for 10 days. Bax expression was detected by immunohistochemistry. Prolactin (PRL) in blood serum was measured by radioimmunoassay (RIA). It has been found that both OCT and BC, alone or in combination, significantly reduce the tumor weight. Both OCT and BC suppressed PRL levels, but the inhibitory effect of BC was stronger than that of OCT. It has been found that the treatment with OCT and BC, alone or in combination, causes a significant increase in Bax expression in the rat prolactinoma cells. Our findings indicate that anti-tumoral action of bromocriptine and to some extent the action of octreotide in the experimental rat prolactinoma is connected with the induction of apoptosis and is associated with increased Bax expression.
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PMID:The effect of octreotide and bromocriptine on expression of a pro-apoptotic Bax protein in rat prolactinoma. 1504 98

To determine the inhibitory profile of the novel somatostatin (SRIF) analog SOM230 with broad SRIF receptor binding, we compared the in vitro effects of SOM230, octreotide (OCT), and SRIF-14 on hormone release by cultures of different types of secreting pituitary adenomas. OCT (10 nM) significantly inhibited GH release in seven of nine GH-secreting pituitary adenoma cultures (range, -26 to -73%), SOM230 (10 nM) in eight of nine cultures (range, -22 to -68%), and SRIF-14 (10 nM) in six of six cultures (range, -30 to -75%). The sst analysis showed predominant but variable levels of somatostatin receptor (sst)(2) and sst(5) mRNA expression. In one culture completely resistant to OCT, SOM230 and SRIF-14 significantly inhibited GH release in a dose-dependent manner with an IC(50) value in the low nanomolar range. In the other cultures, SOM230 showed a lower potency of GH release inhibition (IC(50), 0.5 nM), compared with OCT (IC(50), 0.02 nM) and SRIF-14 (IC(50), 0.02 nM). A positive correlation was found between sst(2) but not sst(5) mRNA levels in the adenoma cells and the inhibitory potency of OCT on GH release in vivo and in vitro, and the effects of SOM230 and SRIF-14 in vitro. In three prolactinoma cultures, 10 nM OCT weakly inhibited prolactin (PRL) release in only one (-28%), whereas 10 nM SOM230 significantly inhibited PRL release in three of three cultures (-23, -51, and -64.0%). The inhibition of PRL release by SOM230 was related to the expression level of sst(5) but not sst(2) mRNA. Several conclusions were reached. First, SOM230 has a broad profile of inhibition of tumoral pituitary hormone release in the low nanomolar range, probably mediated via both sst(2) and sst(5) receptors. The higher number of responders of GH-secreting pituitary adenoma cultures to SOM230, compared with OCT, suggest that SOM230 has the potency to increase the number of acromegalic patients which can be biochemically controlled. Second, compared with OCT, SOM230 is more potent in inhibiting PRL release by mixed GH/PRL-secreting adenoma and prolactinoma cells.
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PMID:The novel somatostatin analog SOM230 is a potent inhibitor of hormone release by growth hormone- and prolactin-secreting pituitary adenomas in vitro. 1507 Sep 15

The clinical characteristics of 84 patients with pituitary tumour who had troublesome headache were investigated. The patients presented with chronic (46%) and episodic (30%) migraine, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT; 5%), cluster headache (4%), hemicrania continua (1%) and primary stabbing headache (27%). It was not possible to classify the headache according to International Headache Society diagnostic criteria in six cases (7%). Cavernous sinus invasion was present in the minority of presentations (21%), but was present in two of three patients with cluster headache. SUNCT-like headache was only seen in patients with acromegaly and prolactinoma. Hypophysectomy improved headache in 49% and exacerbated headache in 15% of cases. Somatostatin analogues improved acromegaly-associated headache in 64% of cases, although rebound headache was described in three patients. Dopamine agonists improved headache in 25% and exacerbated headache in 21% of cases. In certain cases, severe exacerbations in headache were observed with dopamine agonists. Headache appears to be a significant problem in pituitary disease and is associated with a range of headache phenotypes. The presenting phenotype is likely to be governed by a combination of factors, including tumour activity, relationship to the cavernous sinus and patient predisposition to headache. A proposed modification of the current classification of pituitary-associated headache is given.
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PMID:The clinical characteristics of headache in patients with pituitary tumours. 1588 39

Prolactinomas are the more prevalent functioning pituitary tumors, and dopamine agonist drugs (DA) are the main therapeutic option for patients harboring such tumors. Bromocriptine (BRC) resistance, defined as failure to normalize prolactin (PRL) and/or to shrink the tumor is reported in 5 to 18% of the patients treated with this drug, the first DA widely used. Cabergoline (CBG) can bring PRL to normalization and reduce tumor size in up to 86% and 92% of the patients, respectively. Even with this newer DA, a subset of patients does not respond to therapy and are truly resistant. The mechanisms for resistance are not yet fully clarified, so the treatment for the resistant prolactinoma is still a challenge. Transsphenoidal surgery associated or not to radiotherapy is an important tool, but PRL may not normalize, mainly in macroprolactinomas. Treatment with sex steroids or ovulation induction can solve the hypogonadism or infertility, when the tumor growth is under control. New drugs as anti-estrogens, new DA, specific analogs for somatostatin receptor subtypes, chimeric molecules associating dopamine and somatostatin effect, and PRL antagonists are under investigation and can be future alternatives for DA resistance.
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PMID:[Dopamine-agonist resistant prolactinomas: diagnosis and management]. 1644 47

Juvenile cystinosis was diagnosed in a patient who presented with severe headache attacks and photophobia. Treatment with oral cysteamine and topical cysteamine eye drops was started. One-and-a-half years later, he developed unilateral gynecomastia and elevated prolactin and growth hormone levels. A pituitary macroprolactinoma was discovered and successfully treated with the dopamine agonist cabergoline. Increased serum growth hormone levels were attributed to enhanced growth hormone production by the prolactinoma and somatostatin inhibition by cysteamine. Although the occurrence of prolactinoma in this patient could be a simple coincidence, it might also be a rare yet unrecognised complication of cystinosis.
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PMID:Growth hormone producing prolactinoma in juvenile cystinosis: a simple coincidence? 1763 22

Cortistatin (CST) shares high structural homology with somatostatin (SST) and binds all SST-receptors (SST-R) subtypes with similar affinity. However, CST actions, tissue expression patterns and regulation do not fully overlap with those of SST, and, moreover, CST, but not SST, also binds and activates proadrenomedullin N-terminal peptide receptor (MrgX2) and shows binding affinity to ghrelin receptor (GHS-R1a). Several studies performed to clarify the endocrine actions of CST, compared with SST, showed that, in humans, CST and SST share the same endocrine actions, i.e. inhibition of GH and insulin secretion in physiological conditions and in acromegaly. A similar inhibitory effect on PRL and ACTH secretion was shown in acromegaly, prolactinoma or in Cushing's disease. This identity of endocrine actions by CST and SST suggests that SST-R activation by CST overrides any other independent action of this peptide mediated by other receptors. Thus, in terms of endocrine actions, CST can well be considered a natural alternative to SST.
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PMID:Endocrine actions of cortistatin: in vivo studies. 1828 Nov 48

Pituitary tumors come to clinical attention due to endocrine dysfunction, distortion of local structures surrounding the pituitary fossa, or as an incidental finding during neuroimaging for headache. Explanations for pituitary tumor-associated headache include stretching of the dura mater and invasion of pain-producing structures within the cavernous sinus. However, small functional pituitary lesions may present with severe headache without cavernous sinus invasion or suprasellar extension. Prolactinomas and growth hormone-secreting tumors have a high prevalence of rare headache phenotypes with or without autonomic features, suggesting that biochemical abnormalities within the hypothalamo-pituitary axis may play a role in headache. Somatostatin analogues may be highly effective at aborting headache associated with functionally active pituitary lesions, particularly in the case of acromegaly. A proposed mechanism for this is inhibition of nociceptive peptides. This article summarizes the clinical features, pathophysiology, and potential treatment approaches to pituitary tumor-associated headache.
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PMID:Chronic headache and pituitary tumors. 1841 28

Multiple endocrine neoplasia type 1 (MEN 1) is a syndrome characterized by tumors of the parathyroid glands, pancreatic islet cells, duodenum, and pituitary gland. We report a case of cervical metastases of glucagonoma with MEN 1. The patient was a 34-year-old woman admitted to our hospital with epigastric pain. Her medical history included two resections of prolactinoma and two upper GI hemorrhages secondary to duodenal ulcers. Computed tomography (CT) showed two hypervascular lesions in the tail of the pancreas and cervical ultrasound showed multiple hypoechogenic ovoid images in the neck. A cervical CT scan confirmed two 15-mm lymph nodes in the left cervical region and 111In-DOTATOC imaging showed focal abnormal somatostatin expression in the pancreatic tail and the cervical nodes. The patient had asymptomatic hypoglycemic episodes, with blood sugar levels as low as 30 mg/dl, which raised our suspicion of MEN 1 associated with pancreatic insulinoma. Thus, we performed a distal pancreatectomy with bilateral cervical dissection and parathyroid gland resection. Histopathological examination revealed 12 pancreatic tumors as well as metastases in four cervical lymph nodes. The resected parathyroid glands had normal structure, suggesting parathyroid hyperplasia. A follow-up CT scan, 18 months after surgery, showed new tumors in the head of the pancreas and in the duodenal wall. A pancreatoduodenectomy was performed and histopathological examination revealed nine nonfunctioning endocrine tumors in the pancreas, one tumor in the duodenal wall, and metastases in two peripancreatic lymph nodes. The patient recovered well and remains asymptomatic.
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PMID:Cervical metastases of glucagonoma in a patient with multiple endocrine neoplasia type 1: report of a case. 1903 43


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