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

We examined effects of sodium valproate, a gamma amino butyric acid (GABA)-transaminase inhibitor, on the secretion of immunoreactive (IR)-ACTH and IR-beta-endorphin/LPH from cultured rat anterior pituitary cells to determine whether sodium valproate has a direct action on the secretion of ACTH and its related peptides from the cultured rat anterior pituitary gland. During the 3 h incubation, the basal secretion of IR-ACTH and IR-beta-endorphin/LPH decreased to 50.8% and 58.3%, respectively, of the control concentration after adding 10(-7) M sodium valproate into the incubation media and to 67.7% and 69.3%, respectively, of the control levels with 10(-8) M sodium valproate. However, sodium valproate at a concentration of 10(-6) M or 10(-9) M did not affect the basal concentration of IR-ACTH and IR-beta-endorphin/LPH. Sodium valproate at a concentration of 10(-7) M significantly attenuated the stimulated release of IR-ACTH and IR-beta-endorphin/LPH by 10(-9) or 10(-10) M of ovine corticotrophin releasing factor. These results indicate that sodium valproate could directly effect rat anterior pituitary cells to suppress both basal and stimulated release of proopiomelanocortin derived peptides and this supports the hypothesis that sodium valproate has a direct effect at the pituitary corticotroph in reducing plasma ACTH.
 ...
PMID:Effect of sodium valproate on the secretion of proopiomelanocortin derived peptides from cultured rat anterior pituitary cells. 256 Dec 74

The effects of low doses (0.03 and 0.1 microgram/kg) of ovine CRH (oCRH) on plasma beta-endorphin/beta-lipotropin (beta End/beta LPH), ACTH, and corticosteroid levels were studied in normal men. The 0.03 microgram/kg oCRH dose produced a reproducible response, with a rapid increase in plasma oCRH to peak levels between 45 and 95 fmol/mL and an appropriate doubling of plasma peptide and corticosteroid concentrations. The relationship between the corticosteroid rise and the rapid beta End/beta LPH and ACTH declines suggested negative feedback by corticosteroids on the release of these pituitary products. Plasma oCRH levels were proportionate to those reported in studies using much higher oCRH doses, and produced plasma oCRH levels in the reported range for the hypophyseal portal circulation. Molecular sieving of the beta End-immunoreactive materials in basal and post-oCRH (0.1 microgram/kg) plasma samples revealed an average basal beta End to beta LPH ratio of 1:1.5; 15 min after oCRH stimulation the average ratio was 4:1. We conclude that a low (threshold) dose of oCRH can reliably stimulate POMC peptide secretion and may preferentially release beta End from the anterior pituitary.
 ...
PMID:Effects of low dose ovine corticotropin-releasing hormone in humans: endocrine relationships and beta-endorphin/beta-lipotropin responses. 282 22

A lipolytic activity for beta-endorphin (beta EP) has been recently suggested both in vitro and in vivo. In our study we evaluated the relationship between beta EP and blood lipid pattern in Type 2 (non-insulin dependent) diabetic patients. Plasma beta EP, together with plasma beta-lipotropin (beta LPH), ACTH, cortisol and plasma insulin (IRI), was measured by RIA after silicic acid plasma extraction and Sephedex G-75 column chromatography. Although reduced beta EP (7.12 +/- 3.8 fmol/ml) and increased beta LPH (9.3 +/- 3.7 fmol/ml) levels were found in diabetic patients, compared to controls (8.53 +/- 3.3 fmol/ml, p less than 0.05 and 8.34 +/- 2.6 fmol/ml, p less than 0.05, respectively), higher plasma beta EP concentrations were demonstrated in hyperlipidemic diabetic patients (10.3 +/- 3.9 fmol/ml) than in patients with normal blood lipid pattern (4.85 +/- 1.45 fmol/ml, p less than 0.001). Several positive correlations between beta EP, plasma free fatty acids (r = 0.75, p less than 0.001), triglycerides (r = 0.84, p less than 0.001) and VLDL (r = 0.80, p less than 0.001) were found in our patients independently of overweight, hypoglycemic treatment, plasma IRI levels and of the degree of metabolic control. A higher prevalence of micro- and macrovascular complications was demonstrated in hyperlipidemic than in normolipidemic patients. Blood lipid disorders might therefore be associated with increased plasma beta EP levels in Type 2 diabetes.
 ...
PMID:Plasma beta-endorphin, free fatty acids and blood lipid changes in type 2 (non-insulin dependent) diabetic patients. 283 29

The parenchymal cells of the pars intermedia (PI) and corticotrophs of the pars distalis (PD) synthesize pro-opiomelanocortin (POMC), which, through posttranslational processing, gives rise to a group of structurally related peptides, including MSHs, ACTH, CLIP, LPHs and endorphins. We investigated the control of release of these peptides using an in vitro system. We perifused either intact neurointermediate lobes (NI) or PD halves obtained from rats. Perifusion medium and tissue extracts were subjected to a battery of bioassays (BA) and radioimmunoassays (RIA) (including MSH-BA, alpha-MSH-RIA, ACTH-BA, ACTH-RIA, LPH-RIA) and a receptor-binding assay for morphine-like activity (MLA). The relative amounts of released peptide activities were examined under basal conditions and after challenging with synthetic ovine corticotrophin-releasing factor (CRF) and somatostatin. CRF stimulated the release of all assayed peptides from both the PD and PI in a dose-related manner. Stimulated release was immediate (within 3 min), constant, reversible and repeatable. Somatostatin (up to 100 ng/ml) did not alter basal release from either PD or PI. Somatostatin did block CRF-induced release from the PI but not from the PD. These observations support an action of both CRF and somatostatin in the control of secretion of POMC-derived peptides from the PI.
 ...
PMID:Release of pro-opiomelanocortin-derived peptides from the pars intermedia and pars distalis of the rat pituitary: effect of corticotrophin-releasing factor and somatostatin. 286 90

Assays for beta-endorphin (BE) and its precursors such as beta-lipotropin (LPH) in cerebrospinal fluid (CSF), plasma and some tissues have been difficult because of their low concentrations in limited sample volumes, the non-specificity of most antisera. These problems are compounded by the lack of suitable separation methods. Similar problems exist for the enkephalins, tachykinins and dynorphins, among others. This study reports a high-performance liquid chromatographic (HPLC) separation method in which BE and LPH are well separated from each other and which also separates other neuropeptides of interest. The method uses volatile solvents which do not interfere with radioimmunoassay (RIA). Thus by combining HPLC with RIA the method offers, for the first time, a specific assay method for the endorphin, enkephalin and dynorphin families of peptides which does not suffer from the uncertainties in RIA due to cross-reactivities of antisera. Peptide concentrations obtained from the CSF of a small group of chronic pain patients are also presented.
 ...
PMID:Combined high-performance liquid chromatographic-radioimmunoassay method for the analysis of endorphins, enkephalins and other neurotransmitter peptides. 289 17

Hormones are extracted from plasma with varying efficiency. Thus, markers or internal standards are often needed, to monitor and correct for extraction losses. To do so is difficult in the case of peptide hormones because radioactive recovery markers either have a low specific activity or, if labeled with iodine, may not be fully representative because of alterations in their size and charge. More importantly, markers labeled with 125I can interact in, and thus compromise, the subsequent radioimmunoassay. AtT-20 mouse pituitary tumor cells, which can be stimulated to synthesize and secrete pro-opiomelanocortin peptides, can biosynthetically label beta-lipotropin (beta-LPH) with [35S]methionine. The labeled peptide, which is co-eluted with unlabeled beta-LPH in "high-performance" liquid chromatography, is fully immunoprecipitable and has a specific activity of 34 Ci/g. We use this labeled peptide to monitor the recovery of beta-LPH in silicic acid extraction from plasma. This peptide is an ideal marker of analytical recovery because it does not interfere in subsequent radioimmunoassays.
 ...
PMID:Biosynthesized [35S]methionine-labeled pro-opiomelanocortin peptides as novel recovery markers in radioimmunoassay of peptide hormones. 293 87

To study the role of opioid peptides in human obesity, plasma beta-endorphin (beta EP), beta-lipotropin (beta LPH), and cortisol resting values, circadian rhythms, and responses to hypoglycemia were studied in 6 prepubertal and 6 pubertal obese adolescents (at least 40% above ideal body weight) and in 10 normal subjects matched for age, sex, and pubertal development. Baseline plasma beta LPH and beta EP concentrations in both obese children and adolescents were twice as high as those in normal controls, while cortisol levels were not different. Cortisol, beta EP, and beta LPH levels had a clear circadian rhythmicity in all subjects, with the exception of obese pubertal boys whose plasma beta EP concentrations were constant throughout the day. After insulin administration, the fall in blood sugar was similar in all groups. Plasma cortisol and beta EP responses were similar in both obese and normal prepubertal subjects. In obese pubertal adolescents, beta EP did not increase significantly after hypoglycemia, although it did increase in normal weight pubertal subjects. In normal prepubertal subjects, the circadian rhythms of beta EP and beta LPH secretion and release induced by hypoglycemia suggest the presence of a well developed neuroendocrine control of proopiomelanocortin-related peptide secretion. In prepubertal obese children, the increased plasma beta EP and beta LPH levels with the maintenance of their circadian rhythm and responsivity to hypoglycemia suggest overactivity of anterior pituitary secretion. In obese adolescents, in spite of the normal rhythm of beta LPH and cortisol, beta EP levels did not change throughout the day, thus suggesting beta EP secretion from nonpituitary sources in these subjects. The present study indicates a possible direct role for hyperendorphinemia in the induction of overeating in obese children and adolescents.
 ...
PMID:Hyperendorphinemia in obese children and adolescents. 293 22

In order to assess whether a central hypothalamic impairment could account for the pro-opiomelanocortin (POMC)-related peptide over-secretion in depressive disorders, plasma B-lipotropin (B-LPH), B-endorphin (B-EP) and cortisol concentrations were measured in 9 patients affected by neurotic depression: every 4 h over a 24-h period; in response to insulin-induced hypoglycaemia (0.1 IU/kg body weight), and during dexamethasone (DXM) administration (0.5 mg X 4/day for 2 days). Eight age-matched healthy volunteers (controls) were also studied. B-EP and B-LPH were determined by specific radioimmunoassays after plasma extraction and gel chromatography. Compared with the controls, the patients showed a 3 times higher plasma B-EP, twice the normal B-LPH levels, and a 20% cortisol increase. The neurotic depressed patients showed and evening-related decrease in the levels of the 3 hormones, expressed as mean values, similar to that in the controls, whereas the single cosinor analysis revealed a significant circadian rhythm of B-LPH and B-EP only in 3 and 2 patients, respectively. Insulin-induced hypoglycaemia (ITT) stimulated the release of B-LPH and cortisol in both groups, whereas the B-EP increase was absent in the patients. DXM reduced plasma cortisol and B-LPH levels in controls and patients, but in the latter it failed to reduce the B-EP concentrations. The present data indicate that neurotic depressed patients are characterized by increased activity of the hypothalamic-pituitary-adrenal axis, with maintained circadian rhythmicity.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Dysregulation of plasma pro-opiomelanocortin-related peptides in neurotic depression. 294 Jul 93

The effect of hemodialysis on the plasma concentration of beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) was studied in 11 patients with end-stage renal disease (ESRD). The plasma beta-EP/beta-LPH concentrations measured at 13.00 h were not significantly different in the patients compared to age-matched controls. Furthermore, hemodialysis produced no change in the plasma concentrations of beta-EP/beta-LPH. The elevated levels of beta-EP/LPH previously reported are most likely a reflection of the measurement of these peptides at a time of peak diurnal secretion compounded by a fall in the metabolic clearance rate of the endogenous opioids in ESRD. It remains to be established whether measurement of adronocorticotropic hormone or beta-EP/beta-LPH is more accurate an indicator of the integrity of the hypothalamic-pituitary-adrenal axis in patients with ESRD.
 ...
PMID:Plasma beta-endorphin and beta-lipotropin in patients with end-stage renal disease--effects of hemodialysis. 294 91

The presence of beta-endorphin (beta-E) and beta-lipotrophin (beta-LPH) in human ovary was studied by liquid chromatography and radioimmunoassay, and by immunoperoxidase staining. The mean concentrations (+/- S.E., N=8) of beta-E and beta-LPH in follicular fluid samples collected during the late follicular phase of normal cycles were 1.9 +/- 0.4 pmol/l and 2.9 +/- 0.8 pmol/l, respectively. After hyperstimulation with clomiphene and gonadotropin for in vitro fertilization, the mean concentrations of beta-E and beta-LPH in follicular fluid did not increase significantly, being 3.2 +/- 0.6 and 4.1 +/- 1.0 pmol/l, respectively (N=13). beta-E or beta-LPH were not found in three corpora lutea analysed. Immunohistochemical staining of ovarian tissue did not reveal any beta-E immunoreactivity. Thus the origin of beta-E and beta-LPH in the follicular fluid remained unclear. In 7 women, blood samples were collected from the peripheral and ovarian veins at laparotomy. No significant concentration excess of beta-E or beta-LPH was found in the ovarian venous plasma, suggesting that human ovaries do not secrete significant amounts of beta-E or beta-LPH into the peripheral circulation. It seems that the role of endorphins in the human ovary is less significant than previously proposed for sheep, rat or mouse ovary.
 ...
PMID:Beta-endorphin and beta-lipotrophin in human ovary. 294 78


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>