Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report the history, laboratory findings, and studies performed on a 27-yr-old patient with a metastatic parasellar adenoma of the pituitary and Cushing's syndrome. She developed intense hyperpigmentation and extraordinarily high ACTH levels after bilateral adrenalectomy in 1974. With the exception of marked hyperpigmentation, she did well on glucocorticoid replacement therapy until August 1979, when multiple hepatic nodules were observed during a cholecystectomy. Histological studies and immunoperoxidase staining indicated that these lesions were pituitary tumor metastases. What were presumed to be metastatic lesions also developed in lungs and bone. This combination of liver, bone, and lung metastases from primary pituitary tumors has not previously been reported. Immunoreactive plasma ACTH concentrations were as high as 230,000 pg/ml. Similarly, high levels of plasma immunoreactive beta MSH and immunoreactive beta-endorphin were found. High doses of glucocorticoids reduced the concentration of ACTH to one seventh to one tenth the basal level. The sensitivity of plasma ACTH to exogenous steroid administration strongly suggests that an intact intracellular mechanism for negative feedback control of ACTH secretion persisted within the tumor cells. The rapid rise in ACTH and related peptides and the development of metastases after adrenalectomy suggest that both the secretory capacity and the oncogenic potential of the parasellar tumor were chronically inhibited by glucocorticoid hormones.
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PMID:A pituitary parasellar tumor with extracranial metastases and high, partially suppressible levels of adrenocorticotropin and related peptides. 630 34

The AtT-20 cell, a mouse pituitary tumor line that secretes adrenocorticotropin and beta-endorphin, sorts the proteins it externalizes into two exocytotic pathways. Cells that are labeled with [35S]methionine or [35S]sulfate can be shown to transport three acidic polypeptides (65,000, 60,000, and 37,000 mol wt) and at least two sulfated macromolecules into storage secretory granules. When the cells are stimulated by the secretagogue 8-bromo-cAMP, these polypeptides are coordinately secreted with mature adrenocorticotropin into the culture medium. In contrast, a completely different set of secreted polypeptides and sulfated macromolecules does not enter a storage form and is transported to the cell surface more rapidly. Their secretion from the cells is constitutive and does not require the presence of secretagogues. These molecules, like a viral membrane glycoprotein described previously (Gumbiner, B., and R. B. Kelly, 1982, Cell, 28:51-59) are not found in isolated secretory granules and therefore must reach the cell surface in a different exocytotic vesicle. The segregation of a subclass of secretory macromolecules into the secretory granules, despite the existence of another potential secretory pathway, suggests that these molecules have specific functions related to regulated hormone secretion or storage. Presumably all of the proteins secreted by the regulated secretory granule pathway share some common property that targets them to the secretory granule.
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PMID:A subclass of proteins and sulfated macromolecules secreted by AtT-20 (mouse pituitary tumor) cells is sorted with adrenocorticotropin into dense secretory granules. 630 68

Previous work in our laboratory has shown that stimulation of beta 2-adrenergic receptors on mouse anterior pituitary tumor cells causes the secretion of immunoreactive adrenocorticotropin (ACTH). The present study was designed to test the hypothesis that catecholamines can cause the release of ACTH in vivo by the direct stimulation of beta 2-adrenergic receptors in the rat anterior pituitary. Systemic administration of a beta-adrenergic receptor agonist (-)-isoproterenol resulted in an increase in plasma ACTH levels in intact animals and in rats with transected pituitary stalks. This effect could be blocked by the beta-adrenergic receptor antagonist, propranolol, but not by the specific beta 1-adrenergic receptor antagonist, practolol. Salmefamol, a beta 2-adrenergic receptor agonist also elevated plasma ACTH levels in stalk-sectioned animals. Dexamethasone, a glucocorticoid that inhibits the synthesis and release of ACTH from the anterior pituitary but not the intermediate lobe, prevented the elevation of ACTH secretion by (-)-isoproterenol in stalk-transected rats. These data indicate that beta 2-adrenergic receptors are present on anterior pituitary cells and suggest that catecholamines can directly stimulate ACTH secretion.
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PMID:Direct stimulation of beta 2-adrenergic receptors in rat anterior pituitary induces the release of adrenocorticotropin in vivo. 631 39

The tissue-specific processing of proopiomelanocortin (POMC), the precursor of ACTH, beta-endorphin, and their related peptides, is currently of considerable interest. We report a patient with a large aggressive pituitary tumor, Cushing's syndrome, and hyperpigmentation managed by transsphenoidal hypophysectomy, bilateral adrenalectomy, and sellar irradiation. Preoperatively, plasma levels of immunoreactive ACTH (ir-ACTH; 280 ng/liter) and beta-endorphin (ir-beta EP; 520 ng/liter) were moderately elevated. Chromatography of the plasma showed two peaks of ACTH immunoreactivity, with the major peak eluting in the void volume, and two major peaks of ir-beta EP, corresponding to the elution positions of beta-lipotropin and beta-endorphin standards. Plasma ir-ACTH and ir-beta EP were not suppressed by high doses of glucocorticoid or bromocriptine, a degree of autonomy more commonly found with POMC production from ectopic sources than that from pituitary tumors. Tissue removed at operation was enzymatically dispersed, and the cells were cultured in suspension, propagated, and passaged sequentially for over 20 passages. Using this cell line, we demonstrated that the biosynthesis of POMC, its pattern of processing, and the release of POMC/ir-beta EP/ir-ACTH in vitro were consistent with the in vivo evidence of autonomous secretion and abnormal processing of POMC by this pituitary tumor.
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PMID:A pituitary tumor producing high molecular weight adrenocorticotropin-related peptides: clinical and cell culture studies. 631 55

The effects of ovine CRF, lysine vasopressin (LVP), and their interrelationships, and rat hypothalamic extract (HME), on ACTH and beta-endorphin release by human pituitary tumor cells from two patients with Nelson's syndrome and one with Cushing's disease and on ACTH and cortisol secretion in vivo were studied. In cultured pituitary tumor cells, both LVP and CRF greatly stimulated ACTH and beta-endorphin release at maximally active concentrations of 0.1 microM and 10 nM, respectively. At these concentrations, the combination of the two substances had an additive or synergistic effect on hormone release. Low concentrations of HME potentiated and/or were synergistic with CRF-mediated ACTH release. In vivo, the combination of CRF (1 microgram/kg) and LVP (10 pressor units) induced greater ACTH release than the sum of the responses to CRF and LVP alone. This synergistic effect of CRF plus LVP concerned only ACTH release, while cortisol release after CRF plus LVP was equivalent to the sum of the maximal increments in this hormone after CRF and LVP alone. The peak levels of cortisol after a combination of CRF and LVP probably reflect the maximum stimulatory capacity of the adrenal cortex. These data support the concept that in man, both ovine CRF and vasopressin are corticotropin-releasing factors which act synergistically. Both substances might well regulate, at the pituitary level, the responsiveness of the pituitary-adrenal axis to stimuli reaching the hypothalamus. A test using ovine CRF and LVP together might provide a better index of total pituitary ACTH reserve than one using the two compounds separately.
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PMID:Corticotropin-releasing factor (ovine) and vasopressin exert a synergistic effect on adrenocorticotropin release in man. 631 46

Implantation of the PRL, ACTH, beta-endorphin (beta-EP), and beta-lipotropin (beta-LPH)-secreting transplantable rat pituitary tumor 7315a resulted in a suppression of the PRL and the ACTH content of the anterior pituitary gland and also of the beta-EP/beta-LPH content of the neurointermediate (NI) lobe. Treatment with bromocriptine further diminished the anterior lobe PRL content, whereas haloperidol partially inhibited this tumor-mediated diminution. The administration of these drugs did not influence the suppressed ACTH content of the anterior pituitary lobe. The diminished beta-EP/beta-LPH content of the NI lobe of tumor-bearing rats became completely normal after treatment with haloperidol, whereas bromocriptine administration further diminished the NI lobe beta-EP/beta-LPH content. There was a close correlation between the anterior pituitary lobe PRL content and the beta-EP/beta-LPH content of the NI lobe in all four groups of rats taken together (including nontumor-bearing controls, control tumor rats, and tumor rats treated with bromocriptine or haloperidol; P less than 0.01). Implantation of the pure PRL-secreting pituitary tumor 7315b resulted in hyperprolactinemia and a suppression of the PRL content of the anterior lobe and the beta-EP/beta-LPH content of the NI lobe, without affecting the ACTH content of the anterior pituitary lobe. There was a negative correlation between the level of the circulating PRL concentration and the beta-EP/beta-LPH content of the NI lobe. These results suggest a possible relationship between the synthesis of PRL by the anterior pituitary lactotroph and of the hormones of the NI lobe. The level of the circulating PRL concentration may play, directly or indirectly, a role in the regulation of both systems.
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PMID:Hyperprolactinemia exerts a negative effect on the beta-endorphin content of the rat neurointermediate pituitary lobe. 632 44

A case report is presented of the need for both bromocriptine and human menopausal gonadotropin (hMG) for induction of ovulation in a patient who developed partial hypopituitarism and persistent hyperprolactinemia even after a transsphenoidal pituitary microadenectomy. The patient, a 27-year old white female, initially presented in 1979 with a history of amenorrhea and galactorrhea after discontinuing oral contraceptives (OCs). Her menstrual cycles had been regular since her menarch at age 13 until she began taking OCs at age 20. Preoperative endocrine evaluation in 1979 revealed serum luteinizing hormone (LH), 9.1 mIU/ml; serum follicle stimulating hormore (FSH), 6.4 mIU/ml; serum thyroid stimulating hormone (TSH), 3.8 mIU/ml; serum prolactine (PRL), 300 ng/ml; serum thyroxine (T4), 6.4 mcg/dl; and an attenuated PRL response to thyrotropin releasing hormone (TRH). Radiographic studies revealed a pituitary tumor of approximately 1 cm in diameter. In July 1979 a transsphenoidal hypophysectomy was performed. Pathologic examination revealed a pituitary adenoma with a monomorphic basophilic cell population with fibrosis and chronic inflammation. The patient required prednisone therapy postoperatively for 3 months secondary to compromised adrenal status. Prednisone therapy was discontinued in October 1979 after a normal cortisol (F) response to induced hypoglycemia was documented. The patient's serum PRL levels remained elevated at 111 ng/ml in August 1979 and 269 ng/ml in October 1979. Her amenorrhea and galactorrhea persisted. Bromocriptine therapy, 2.5 mg 3 times daily, was instituted in October 1979. She became normoprolactinemic, with a serum PRL of 6 ng/ml, and the galactorrhea disappeared but the amenorrhea persisted. In February 1981 she was referred for further consultation on her fertility status. Bromocriptine therapy was discontinued. In April 1981 she underwent a thorough endocrine evaluation. The results indicate that GnRH stimulation was unable to elicit a pituitary gonadotropin response anywhere near normal levels of FSH and LH, thus suggesting pituitary hypogonadotropism. Growth hormone release was subnormal in response to the insulin induced hypoglycemia and L-dopa ingestion. Hyperprolactinemia was obvious but the patient's serum TSH, T4, and adrenocorticotropin (ACTH) levels were normal. A diagnosis of hyperprolactinemia with partial hypopituitarism and gonadotropin deficiency was made. Bromocriptine therapy was reinstituted at 2.5 mg twice daily in June 1981, with good results. In November 1981 her serum PRL was normal, and as she was desirous of pregnancy, ovulation induction with bromocriptine and Pergonal was carried out. The patient is now 6 months pregnant and doing well. This case illustrates the poor functional results for surgery for pituitary microplactinomas.
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PMID:Partial hypopituitarism and hyperprolactinemia: successful induction of ovulation with bromocriptine and human menopausal gonadotropins. 681 37

[Met]enkephalin and [Leu]enkephalin are derived from a protein in bovine adrenal medulla that contains multiple copies of [Met]enkephalin [Kilpatrick, D. L., Taniguchi, T., Jones, B. N., Stern, A. S., Shively, J. E., Hullihan, J., Kimura, S., Stein, S. & Udenfriend, S. (1981) Proc. Natl. Acad. Sci. USA 78, 3265--3268.] Here we characterize pro-enkephalin mRNA from bovine and human tissue by use of an oligodeoxynucleotide pentadecamer probe complementary to codons for Tyr-Gly-Gly-Phe-Met ([Met]enkephalin). This probe hybridizes specifically to a species of poly(A)-RNA from adrenal medulla and human pheochromocytoma, (1400--1450 bases), and also to [Met]enkephalin-containing pro-opiomelanocortin mRNAs from bovine pituitary (1200 bases) and from mouse pituitary tumor cell (1100 bases). A cloned cDNA probe (144 bases) complementary to the region of pro-opiomelanocortin mRNA that codes for lipotropin does not hybridize to the RNA from bovine adrenal medulla, demonstrating that the latter RNA is not pro-opiomelanocortin mRNA. The pentadecamer probe was extended to make cDNA with reverse transcriptase after hybridizing it to adrenal poly(A)-RNA. The sequence of an extended cDNA, 62 bases in length, was found to correspond exactly to that expected from the amino acid sequence of peptide E (a bovine adrenal peptide containing [Met]- and [Leu]enkephalin sequences). This cDNA also forms a specific hybrid with the RNA from bovine adrenal and human pheochromocytoma, confirming that these species of RNA are pro-enkephalin mRNA.
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PMID:Partial characterization of the mRNA that codes for enkephalins in bovine adrenal medulla and human pheochromocytoma. 695 89

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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PMID:Calcineurin feedback inhibition of agonist-evoked cAMP formation. 749 91

ACTH is the major regulator of the body's adaptive response to stress and the physiological stimulus for glucocorticoid secretion. In addition to the known negative feedback regulation of ACTH by glucocorticoids, a hypothalamic corticotropin release-inhibiting factor (CRIF) that inhibits ACTH synthesis and secretion has been postulated, but not identified. We previously reported that transfection of prepro-TRH complementary DNA into the mouse anterior pituitary tumor cell line AtT-20 results in inhibition of basal and corticotropin-releasing hormone (CRH)-stimulated ACTH synthesis and secretion, suggesting that one or more of the cryptic peptides encoded within the prepro-TRH precursor has CRIF activity. To narrow the choice of peptides responsible for CRIF activity, we first deleted specific sequences within the prepro-TRH complementary DNA and transfected these constructs into AtT-20 cells. Deletion of sequences encoding amino acids 119-229 resulted in the loss of CRIF activity. Of the peptides encoded within this region, prepro-TRH-(178-199), a 22-amino acid peptide, inhibited basal and CRH-stimulated ACTH synthesis and secretion in cultured primary anterior pituitary cells. As this peptide is processed from prepro-TRH in vivo, is found in the external zone of the median eminence, and is secreted from hypothalamic slices in vitro, prepro-TRH-(178-199) fulfills the criteria for a physiological CRIF. The significance of TRH and CRIF sharing a common precursor opens new areas of research in the integrated regulation of pituitary-adrenal and pituitary-thyroid functions.
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PMID:Corticotropin release-inhibiting factor is preprothyrotropin-releasing hormone-(178-199). 762 93


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