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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This communication reports a method for increasing the speed of separation of bound and free antigen in radioimmunoassay systems with no loss in the specificity of binding. The technique uses a mixture of second antibody and polyethylene glycol. It is not species or antibody specific, and systems using specific first antibodies from rabbit, goat or sheep are all functional. Results for the assay of parathyrin, calcitonin and corticotropin are described here, although the system has been shown to work for triiodothyronine, thyroxin, thyrotropin, thyroxine binding globulin and transferrin. The time taken for the reaction between first and second antibody is in the order of seconds, and the stability of the complex is unchanged over a period of hours.
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PMID:A rapid and specific method for separation of bound and free antigen in radioimmunoassay systems. 22 Mar 74

The internalization of a neuromodulatory adrenocorticotropic hormone (ACTH) analogue, [125I]ebiratide (H-Met(O2)-Glu[125I]His-Phe-D-Lys-Phe-NH(CH2)2NH2), was examined in cultured monolayers of bovine brain capillary endothelial cells (BCEC). HPLC analysis of the incubation solution showed that [125I]ebiratide was not metabolized during the incubation with BCEC. The acid-resistant binding of [125I]ebiratide to BCEC increased with time for 120 min and showed a significant dependence on temperature and medium osmolarity. Pretreatment of BCEC with dansylcadaverine or phenylarsine oxide, endocytosis inhibitors, and 2,4-dinitrophenol, a metabolic inhibitor, decreased significantly the acid-resistant binding of [125I]ebiratide. The acid-resistant binding of [125I]ebiratide was saturable in the presence of unlabeled ebiratide (100 nM-1 mM). The maximal internalization capacity (Bmax) at 30 min was 7.96 +/- 3.27 pmol/mg of protein with a half-saturation constant (Kd) of 15.9 +/- 6.4 microM. The acid-resistant binding was inhibited by basic peptides such as poly-L-lysine, protamine, histone, and ACTH but was not inhibited by poly-L-glutamic acid, insulin, or transferrin. These results confirmed that ebiratide is transported through the blood-brain barrier via an absorptive-mediated endocytosis.
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PMID:Absorptive-mediated endocytosis of an adrenocorticotropic hormone (ACTH) analogue, ebiratide, into the blood-brain barrier: studies with monolayers of primary cultured bovine brain capillary endothelial cells. 132

A method for primary culturing of rat anterior and intermediate/posterior pituitary cells in complete serum-free defined medium (CSFM) is described. Dispersed pituitary cells were prepared by using a multiple enzyme digestion system. Insulin, transferrin and serum albumin were essential additives for maintenance of primary rat pituitary cells in CSFM. Morphological immunocytochemical and RIA studies during three weeks' culture indicated that beta-endorphin-like immunoreactivity (beta-End-IR) was contained in and released from pituitary cells. The secretion rate remained almost constant for 2 weeks after the 5th day in culture. This method provides an ideal in vitro model for studying the effects of various factors on the synthesis and release of beta-endorphin in pituitary cells and the mechanism of regulation of other target gland hormones.
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PMID:[Primary culture of rat pituitary cells in serum-free medium]. 139 42

The binding and internalization of a novel adrenocorticotropic hormone (ACTH) analog having a potent neuromodulating effect, ebiratide (H-Met(O2)-Glu-His-Phe-D-Lys-Phe-NH(CH2)8NH2), by isolated bovine brain capillaries, were examined. Metabolism of [5-125I-His]ebiratide occurred during a 30-min incubation with bovine brain capillaries at 37 degrees C. In the presence of 20 mM EDTA, added to inhibit this metabolism, the medium, after 30 min of incubation, contained 82.3 +/- 0.5% of the unchanged ebiratide. The total binding and acid-resistant binding of [125I]ebiratide increased with time and reached an equilibrium at about 15 min. The total binding and acid-resistant binding at 30 min (as the cell/medium ratios corrected with [14C]sucrose) were 13.07 +/- 0.86 and 5.00 +/- 0.18 microliters/mg of protein, respectively. The acid-resistant binding showed significant dependence on temperature and medium osmolarity. The [125I]ebiratide binding was significantly inhibited by dansylcadaverine, an endocytosis inhibitor. The saturable acid-resistant binding was obtained by the addition of unlabeled ebiratide (100 nM-5 mM), and the maximal internalization capacity (Bmax) at 30 min was 144.2 pmol/mg of protein, with the half-saturation constant (KD) of 62.1 microM. The nonsaturable acid-resistant binding [cell/medium ratio in the presence of the unlabeled compound (1 mM or more)] was 2.2 microliters/mg of protein. The acid-resistant binding was significantly inhibited by human ACTH, poly-L-lysine, protamine and E-2078, a basic peptide, but was not inhibited by poly-L-glutamate, insulin or transferrin. These results demonstrate that ebiratide is transported through the blood-brain barrier via a basic peptide-specific absorptive-mediated endocytosis.
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PMID:Transport mechanism of a new behaviorally highly potent adrenocorticotropic hormone (ACTH) analog, ebiratide, through the blood-brain barrier. 165 Aug 27

The paper is concerned with the experimental data on a ERP signal size in two blood plasma metalloproteins--ceruloplasmin and transferrin and their correlations after intraperitoneal hydrocortisone and corticotropin injections (5 mg and 2.5 U/100 g body weight, respectively) to Wistar adult male rats and after bilateral adrenalectomy. A conclusion has been made that antioxidant activity of the ceruloplasmin-transferrin complex in rat blood plasma is increased with a rise of the corticotropin level but it is decreased with hydrocortisone loading.
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PMID:[The signal intensity of the electron paramagnetic resonance of ceruloplasmin and transferrin in the blood plasma of rats with altered function of the hypophyseal-adrenal cortex system]. 216 30

The growth of the mouse pituitary cell line AtT 20 was studied under different in vitro conditions. A completely defined, serum-free culture medium supported the survival of cells for a period of more than 2 mo. The medium, designed SFI, consisted of basal medium supplemented with transferrin, insulin, putrescine, and selenium. For maintenance of cells during long-term culture, no additional compounds were necessary. The time-dependent increases in cell number during culture with fetal bovine serum (FBS) and under serum-free conditions showed similar properties. Analysis of the effects of different substrata on cell growth demonstrated that polylysine supported adhesion and initial growth of cells to a greater extent than untreated plastic or FBS adsorbed to culture dishes. Synthesis and regulation of proopiomelanocortin (POMC)-mRNA, the precursor-mRNA of adrenocorticotropin (ACTH), could be detected by Northern blot analysis under basal conditions and after incubation with steroids and corticotropin-releasing hormone (CRH), indicating the serum-independent expression of important cellular properties.
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PMID:Serum-free culture of AtT 20 pituitary cells: a system for neuroendocrine studies under defined conditions. 217 66

The present study examined the effects of both insulin and insulin-like growth factor-I (IGF-I) on cell division and specific functions of cultured adrenocortical cells from 100- to 122-day-old ovine fetuses. When culture was performed in a serum-free medium containing transferrin and ascorbic acid, the number of cells increased only slightly (1.2-fold) over a 4-day period. Addition of insulin or IGF-I in the culture medium enhanced the number of cells counted on Day 5. The effect of both peptides was dose-dependent, but 10 ng/ml IGF-I was as potent as 10 micrograms/ml insulin. The acute cyclic adenosine 3',5'-monophosphate (cAMP) and steroidogenic responses to adrenocorticotropin (ACTH1-24) decreased in fetal cells cultured in the absence of insulin or ACTH. Insulin at micromolar concentrations not only prevented this decrease but enhanced the acute ACTH1-24-induced cAMP output on Day 5 over that observed on Day 2. Treatment of fetal cells for 4 days with increasing concentrations of insulin or IGF-I enhanced the acute cAMP and steroidogenic responses (3- to 4-fold) to ACTH1-24 over that of control cells. The ED50 of IGF-I was about 3 ng/ml (congruent to 0.4 nM) whereas that of insulin was about 10 ng/ml (1.7 nM). However, a second plateau was apparent at concentrations of insulin above 1 microgram/ml. The acute cholera toxin stimulation of cAMP production of cells cultured in the absence of insulin or ACTH.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:In vitro effect of insulin and insulin-like growth factor-I on cell multiplication and adrenocorticotropin responsiveness of fetal adrenal cells. 254 62

In order to study the mechanisms of the differentiation of adenohypophysial corticotropic cells, an immuno-cytological study was performed in fetal rat anterior pituitary in vivo and in vitro with antisera against beta-(1-24) and alpha-(17-39) ACTH and beta-LPH, alpha- and beta-endorphins. In vivo, these cells appeared at 16 days of gestation without any difference in the timing of appearance of the two immunoreactivities. The same immunoreactivity was also detected in adenohypophysial primordia explanted from 12 to 15 days of gestation and maintained in organ culture until 21 days by using either medium containing fetal calf serum or medium containing insulin and transferrin instead of fetal calf serum. These immunoreactive cells were first detected in the different experimental primordia after a minimal period of culture, corresponding to a final equivalent of 16 days as in vivo. However, the mean cytoplasmic area of immunoreactive cells increased in relation to the day of explantation whatever the duration of culture. These data suggest: (1) the nature of culture medium used in this study has no influence on the differentiation of the corticotropic cells; (2) this cell type seems to be committed precociously (before day 12) by one or several substances of unknown origin; (3) the normal development seems to require the presence of factors (before day 14) whose nature and origin remain to be elucidated.
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PMID:Comparative study in vivo and in vitro of the differentiation of immunoreactive corticotropic cells in fetal rat anterior pituitary. 629 62

We studied the hormonal millieu and possibility of altered thyroid function in 25 patients in a surgical intensive care unit (ICU) who had severe life-threatening illnesses. Sixteen patients had septic complications and nine patients had multiple-system injuries. On admission to the ICU, serial measurements were begun of thyroxine (T4), triiodothyronine (T3), T4-binding globulin, thyrotropin (thyroid-stimulating hormone [TSH]), corticotropin (adrenocorticotropic hormone [ACTH]), cortisol, prolactin, human growth hormone, catecholamine, insulin and glucose, lactate, retinol-binding protein, prealbumin, and transferrin levels. All patients initially had low normal levels of T4 (4.5 +/- 2 micrograms/dL) and T3 (55 +/- 26 ng/dL), with normal TSH levels (2.3 +/- 2.3 microU/mL) (the "low T3 syndrome"). The 11 surviving patients had their levels increase to normal before leaving the ICU (T4, 7.0 +/- 2.1 micrograms/dL; T3, 110 +/- 48 ng/dL; and TSH, no change). The 14 patients who died showed further decreases before death (T4, 2.6 +/- 2.1 micrograms/dL; T3, 30.6 +/- 23.5 ng/dL; and TSH, 0.9 +/- 0.7 microU/mL). The corticotropin, cortisol, prolactin, and growth hormone levels were normal throughout the study. Catecholamine levels were high initially and decreased in surviving patients. Epinephrine levels increased greatly in nonsurvivors before death, and the norepinephrine-epinephrine ratio decreased from 5.7:1 to 2:1. After protirelin (thyroid-releasing hormone [TRH]) stimulation, the TSH level increased either minimally or not at all in six patients who eventually died. This indicates hypothalamic-pituitary dysregulation or suppression, and altered release and/or peripheral metabolism of T4. Whether this represents a deficiency of thyroid hormone for cell and organ function remains to be established.
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PMID:Altered hormonal activity in severely ill patients after injury or sepsis. 647 95

Using a specific anti-rat transferrin (Tf) antiserum, Tf-like immunoreactivity (Tf-lir) was detected by immunostaining in intact rat pituitaries and in reaggregated pituitary cells cultured in serum-free medium. Tf-lir cells were present in the anterior pituitary (AP), and in the intermediate (IL) and neural lobes (NL). In the AP, Tf-lir cells were oval or polygonal. An unusual topographical distribution was found. Tf-lir cells mainly occurred as dense clusters in the lateral wings. In the central part of the AP, Tf-lir was found in flattened perisinusoidal cells. Double immunostaining for Tf and the different pituitary hormones showed that Tf-lir co-localized with some gonadotrophs and somatotrophs (7% and 3% of Tf-lir cells, respectively, in typical sections). No co-localization was seen with PRL, ACTH, TSH, or alpha-MSH. The distribution of Tf-lir cells and their cell shape completely differed from that of S-100-positive cells in the AP. In the IL, clusters of large stellate Tf-lir cells were found. Again, their distribution completely differed from S-100-positive cells. In the NL, diffuse staining was found. Double immunostaining of paraffin-embedded sections of reaggregate cell cultures of the AP did not reveal any co-localization of Tf-lir with ACTH, alpha-MSH, LH, FSH, TSH, GH, or PRL. In aggregates consisting of NL + IL cells, Tf-lir was located in clusters: no co-localization with ACTH or alpha-MSH could be demonstrated. Reaggregate cell cultures of AP and NL + IL secreted Tf-lir as measured by radioimmunoassay, at least during 21 days of culture. After metabolic labeling with [35S]-methionine and immunoprecipitation of [35S]-methionine-labeled material present in the culture medium of both AP and NL + IL aggregates with anti-Tf antiserum, a 35S-labeled substance was found, which on SDS-PAGE showed an apparent M(r) of approximately 78 KD, corresponding to the M(r) of rat Tf. The present data show that a specific population of cells of rat anterior pituitary is capable of synthesizing, storing, and secreting transferrin or a substance closely related to it. Cells different from melanotrophs and S-100 cells in the IL, as well as pituicytes in the NL, also appear to produce this material. We suggest that transferrin or a transferrin-like substance may have a local role in the transport of iron or other metals or may play a role as growth factor in the three lobes of the pituitary gland.
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PMID:Production of transferrin-like immunoreactivity by rat anterior pituitary and intermediate lobe. 760 20


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