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At least 19 recordsLinked to original sources
PubMed1979

Endorphins in schizophrenia: hemodialysis/hemoperfusion are ineffective in clearing beta-Leu5-endorphin and beta-endorphin from human plasma.

Beta-Leu5-endorphin, a relative of "normal" beta-endorphin in which leucine is substituted for methionine at position 5 of the latter, has previously been found in high concentrations in the dialysate of schizophrenics. Its removal from plasma by means of hemodialysis has been claimed to relive the symptoms of schizophrenia. Using a highly sensitive radioimmunoassay of equal sensitivity to beta-endorphin and beta-leu5-endorphin, we have compared the plasma immunoreactivity of three schizophrenic patients befofe and after performance of their first session of membrane hemoperfusion. As compared to normal subjects, plasma beta-endorphin-like immunoreactivity was not greatly elevated in the schizophrenic patients before hemoperfusion.However, instead of the expected decrease, a consistent increase in the plasma levels of immunoreactive beta-endorphin was detected after hemoperfusion. In vitro experiments in which two different membranes and hemodialysis as well as hemoperfusion were used, revealed that synthetic beta-leu5-endorphin (and beta-endorphin) from human plasma was not cleared with any of these methods. This finding is inconsistent with the hypothesis that the claimed therapeutic effects of hemodialysis in schizophrenics are due to the removal of a beta-endorphin-like material from the plasma. Consequently, it seems to be unprobable that high concentrations of beta-leu5-endorphin occur in the dialysate or ultrafiltrate of schizophrenics.

Adult↗
PubMed1990

Effects of chronic treatment with haloperidol and bromocriptine on the processing of beta-endorphin to gamma- and alpha-endorphin in discrete regions of the rat pituitary gland and brain.

beta-Endorphin is the putative precursor molecule of gamma- and alpha-endorphin. To investigate whether long-term changes in the activity of cells producing beta-endorphin are paralleled by alterations in the enzymatic processing of beta-endorphin, the effects of chronic treatment of rats with dopamine (DA) receptor ligands were examined on the content of immunoreactivity of beta-, gamma- and alpha-endorphin of dissected regions of the pituitary gland and the brain. Treatment with the DA receptor antagonist, haloperidol, resulted in a significant increase in the concentration of immunoreactivity for beta-, gamma-, and alpha-endorphin in the neurointermediate lobe, and of beta-endorphin in the anterior lobe of the pituitary gland. Levels of immunoreactivity of alpha-melanotropin and beta-endorphin in plasma were elevated, but those of corticosterone were decreased. This indicates that, in the intermediate lobe, both the biosynthetic and the secretory activity of cells producing beta-endorphin had increased, whereas in the anterior lobe, the secretory activity of beta-endorphin cells had decreased. No effects were observed on the ratios beta-endorphin/gamma-endorphin and beta-endorphin/alpha-endorphin in the intermediate lobe. In the anterior lobe however, the ratio beta-endorphin/alpha-endorphin had significantly increased. The effects of chronic treatment with the DA receptor agonist, bromocriptine, on levels of hormones in pituitary and plasma were opposite to those induced by haloperidol. In the brain, treatment with haloperidol selectively increased the content of immunoreactivity for beta-, gamma- and alpha-endorphin of the hypothalamus and the hippocampus and did not affect levels of peptides in the other regions of the brain studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Synthesis and receptor binding activity of elephant beta-endorphin, a beta-endorphin homolog with highly potent analgesic activity.

Elephant beta-endorphin and its analog, elephant beta-endorphin(6-31) were synthesized by standard solid phase method. Receptor binding activity showed that elephant beta-endorphin was five to six times more potent than human beta-endorphin in its ability to bind to opiate receptors on rat brain membrane. In a previous study (Wong, C.-L., Wai, M.-K., Cheng, H.-C., Chung, D. & Yamashiro, D (1990) Clinical and Experimental Pharmacology and Physiology 16, 33-37), tail flick test for intracerebroventricularly administered beta-endorphin showed that the antinociceptive potency of elephant beta-endorphin was seven to eight times higher than that of human beta-endorphin in mice. Results from both studies suggest that elephant beta-endorphin was a much more potent antinociceptive agent than human beta-endorphin in tail flick test and its higher analgesic activity might be due to its higher affinity for opiate receptors in the brain.

Amino Acid Sequence↗
PubMed1992

Measurement of beta-endorphin in human plasma by high-performance liquid chromatography with electrochemical detection: validation of a method employing the simultaneous purification and concentration of beta-endorphin.

The simultaneous purification and concentration of synthetic human beta-endorphin from plasma is described, which when used together with an appropriate isocratic high-performance liquid chromatographic-electrochemical detection (HPLC-ED) system allows the determination of elevated physiological levels of beta-endorphin. Purification of plasma was gained by flash-freezing in liquid nitrogen, acidifying with 100 microliters of trifluoroacetic acid (10%, v/v) per ml of plasma, thawing at 4 degrees C and centrifuging to remove any precipitate. Solid-phase extraction with silica sorbent was utilised, which allowed further isolation of the analyte, a method of concentration and a procedure whereby beta-endorphin could be transferred to the HPLC mobile phase. Silica sorbent demonstrated greater selectivity than C18 for synthetic human beta-endorphin and, in addition, provided improved recovery of this analyte when utilising elution volumes of 500 microliters or less. Proteolytic degradation and heparin-induced high-affinity binding in plasma were shown not to effect the recovery of beta-endorphin if blood was rapidly chilled and plasma quickly obtained, frozen and acidified. Validation of this purification/concentration method using [125I]beta-endorphin demonstrated a recovery of 85.6% which was not jeopardised when concentrating the sample twenty-fold. This provided an increase in the sensitivity of detection, when used in conjunction with HPLC-ED, from 5 ng/ml to 250 pg/ml.

Aprotinin↗
PubMed1978

Endorphins in chronic pain. I. Differences in CSF endorphin levels between organic and psychogenic pain syndromes.

A series of 37 patients with chronic pain was investigated with regard to neurologic and psychiatric variables. Twenty of the patients were classified as having mainly organic (= somatogenic) pain syndromes while 17 patients were rather suffering from psychogenic pain syndromes. Samples of lumbar cerebrospinal fluid (CSF) were obtained from the patients and analyzed for the presence of opiate receptor-active material, here called endorphins. Patients classified as having mainly organic pain syndromes were found to have significantly lower endorphin levels than patients with predominantly psychogenic pain syndromes. In the total group of patients as well as in the two subgroups, there was a significant correlation between CSF endorphin levels and the depth of depressive symptomatology as reported by the patients. On the other hand, there was no correlation between CSF endorphin levels and extent of anxiety or motor retardation. It is concluded that CSF endorphins reflect central processes involved in chronic pain syndromes.

Adult↗
PubMed1978

Presence of immunoreactive beta-endorphin in normal human plasma: a concomitant release of beta-endorphin with adrenocorticotropin after metyrapone administration.

To elucidate whether or not beta-endorphin exists in plasma of normal subjects, plasma extracts obtained before and after metyrapone administration were subjected to gel exclusion chromatography, and fractions obtained were assayed by a sensitive radioimmunoassay for beta-endorphin. The basal plasma level of beta-endorphin was 5.8 +/- 1.1 pg/ml (mean +/- SE, n = 5), which rose significantly to the level of 48.9 +/- 3.8 pg/ml after a single oral dose (30 mg/kg of body wt) of metyrapone administration (P less than 0.001). Plasma ACTH levels also increased from the mean basal level of 73 +/- 4 pg/ml to 269 +/- 41 pg/ml after metyrapone administration. These results indicate that beta-endorphin, distinct from beta-lipotropin, exists in normal human plasma and that it is released from the pituitary concomitantly with ACTH.

Adrenocorticotropic Hormone↗
PubMed1979

ACTH, beta-LPH and beta-endorphin in pituitary adenomas of the patients with Cushing's disease: activation of beta-LPH conversion to beta-endorphin.

ACTH, beta-lipotropin (beta-LPH) and beta-endorphin concentrations were determined in pituitary adenomas of the patients with Cushing's disease. Immunoreactive ACTH and beta-endorphin were present in high concentrations and essentially equimolar amounts in pituitary adenomas. beta-LPH conversion to beta-endorphin was activated in pituitaries associated with ACTH/beta-LPH producing adenomas. Immunoreactive ACTH and beta-endorphin concentrations were markedly suppressed in the surrounding tissues.

Adenoma↗
PubMed1976

[Endorphins, hypothalamic and neurohypophysial peptides with morphinomimetic activity: isolation and molecular structure of alpha-endorphin].

From a crude extract of Porcine neurohypophysis-hypothalamus we have isolated several peptides called endorphins which mimic opiated in a classical bioassay for morphine. Similarly they bind to the stereospecific synaptosomal opiates receptors of Rat brain in competition to 3 H-etorphine. The primary structure of alpha-endorphin is H-Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-OH. Met-enkephalin is the N-terminal pentapeptide of alpha-endorphin. Alpha-endorphin has the same sequence as that of the fragment TYR 61 to Thr 76 of the beta-lipotropins.

Amino Acid Sequence↗
PubMed1979

Systemic administration of Met-enkephalin, (D-Ala2)-Met-enkephalin, beta-endorphin, and (D-Ala2)-beta-endorphin: effects on eating, drinking and activity measures in rats.

Rats were given four daily, interperitoneal injections (80 micrograms/kg) of Met-enkephalin, (D-Ala2)-Met-enkephalin-NH2, beta-endorphin, (D-Ala2)-beta-endorphin or the diluent (0.9% NaCl acidified to, 0.01 M with acetic acid). Animals were subsequently tested for food and water inake and activity. Met-enkephalin injections did not affect any of the measures but its (D-Ala2) analog reduced food intake and some of the activity measures in a complicated way. beta-Endorphin injections did not affect food or water intake; in familiar situations these animals were less active while novel situations seemed to potentiate activity. The (D-Ala2) analog reduced wheel running over 24 hours.

Animals↗
PubMed1992

Central changes of beta-endorphin-like immunoreactivity during rat tonic pain differ from those of purified beta-endorphin.

Several studies have described changes in beta-endorphin-like immunoreactivity (beta-ELI) in the rat brain in response to pain and stress stimuli. In order to ascertain the components of beta-ELI, brain samples of rats experiencing acute prolonged (tonic) pain were evaluated for their beta-ELI and later submitted to a chromatographic purification allowing the measurement of beta-endorphin (beta-EP) and acetyl beta-EP. The chromatographic analysis of both ventromedial hypothalamus (VMH) and periaqueductal grey (PAG) homogenates indicates that beta-ELI is distributed in several fractions including shortened forms of beta-EP and their respective acetylated compounds. Quantitatively, while beta-ELI in formalin-injected animals was increased by 48% in VMH and 45% in PAG in respect to controls, the net increase of purified beta-EP was 1100% and 470%, respectively, for VMH and PAG. Moreover, the maximal increase of beta-ELI was evident at 120 min, in both tissues. In contrast, the beta-EP peak was reached at 30 min in VMH and at 60 min in PAG. Acetyl beta-EP was unchanged by treatment in both central areas. No correlation of beta-ELI and beta-EP was found in VMH. These data demonstrate that the evaluation of beta-ELI gives a poor estimate of beta-EP changes, due to several components of the endorphin family.

Animals↗
PubMed1990

[Structural organization of [met]enkephalin and endorphin molecules. II. Theoretical conformation analysis of alpha-, gamma- and delta-endorphins].

Conformational energy calculations were carried out for neuropeptides alpha-, gamma- and delta-endorphins, which are 1-16, 1-17 and 1-19 fragments respectively, of beta-endorphin. The proposed computational scheme yielded all possible low-energy conformational sets for these hormones. Specific features of spatial organization of each compound and similarities of their structures are discussed.

Amino Acid Sequence↗
PubMed1991

Endoproteolytic conversion of beta-endorphin-1-31 to beta-endorphin-1-27 potentiates its central cardioregulatory activity.

Brain neurons that express the pro-opiomelanocortin gene secrete multiple forms of beta-endorphin (beta E) which subserve diverse bioregulatory processes. beta E-1-31, for example, is a potent analgetic but beta E-1-27 acts as an opioid antagonist and beta E-1-26, as well as the N-acetyl derivatives of all 3 peptides, lack opioid receptor activity. The present study examines the effects of beta-endorphin processing on its central cardioregulatory potency. Consistent with previous reports, intracisternal beta E-1-31 (1.5 nmol) injection lowered mean arterial pressure (MAP); MAP was reduced by 29.7 +/- 3.9 mm Hg at 60 min and returned toward baseline by 120 min. Unexpectedly, beta E-1-27 displayed a 10-fold greater hypotensive potency than beta E-1-31. At 0.15 nmol, it produced a response equivalent to 1.5 nmol beta E-1-31 while 1.5 nmol beta E-1-27 sustained a maximal reduction in MAP (49.2 +/- 3.9 mm Hg) throughout the 120-min test period. In contrast, beta E-1-26 and N-acetyl-beta E-1-26, -1-27 and -1-31 were inactive at 1.5 nmol. Bradycardia accompanied the depressor response to the higher beta E-1-27 dose but not to beta E-1-31. Naloxone pretreatment completely blocked the depressor effects of both beta E-1-31 and beta E-1-27, and reversed the bradycardia produced by beta E-1-27, suggesting that both peptides act through opioid receptors. beta E-1-27 also stimulated catecholamine release from the perfused adrenal gland but beta E-1-31 was inactive. These findings emphasize the importance of regionally selected post-translational processing in defining the functional specificity of beta E peptides.

Adrenal Glands↗
PubMed1978

[Antigenic determinants of beta-LPH, beta-MSH, alpha-endorphin, ACTH and alpha-MSH revealed by anti-beta-endorphin in neurons of the human infundibular nucleus].

Comparison of adjacent serial sections of the tubero-infundibular region of Human adult hypothalamus demonstrates that the same perikarya, axons and terminals are stained both with anti-beta-endorphin and anti 17-39 ACTH antisera. The most immunoreactive of these neurons are also revealed with anti alpha-endorphin, anti alpha and beta-MSH, anti-1-24 ACTH and anti beta-LPH. These results suggest that neurons of the infundibular nucleus can store and probably secrete peptide similar to propiocortin or fragment(s) of this molecule.

Adrenocorticotropic Hormone↗
PubMed1976

Isolation, primary structure, and synthesis of alpha-endorphin and gamma-endorphin, two peptides of hypothalamic-hypophysial origin with morphinomimetic activity.

The isolation and primary structure of two peptides with morphinomimetic activity, obtained from an extract of porcine hypothalamus-neurohypophysis, are described. The amino acid sequence of the two peptides, named alpha-endorphin and gamma-endophin, was determined by mass spectrometry and danxyl-Edman methods to be H-Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-OH and H-Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-Leu-OH, respectively. These correspond to the amino acid sequences present between residues 61 and 76 and residues 61 and 77 of the various beta-lipotropins. A third peptide also obtained in pure form in these studies was found to be an unstable salt of alpha-endorphin.

Amino Acid Sequence↗