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At least 73 records · Page 4Linked to original sources
PubMed1986

Pro-opiomelanocortin messenger ribonucleic acid and posttranslational processing of beta endorphin in spleen macrophages.

We have previously demonstrated low levels of immunoreactive (ir)-beta-endorphin (beta-EP) and ir-ACTH in a subpopulation of mouse spleen macrophages, which is consistent with an involvement of opioid peptides in modulation of immune responses. Gel chromatography studies suggested the presence of an approximately 3.5,000-molecular weight (mol wt) species, putatively beta-EP, an approximately 11.5,000-mol-wt species, putatively beta-lipotropin, and a higher molecular weight species (putative beta-EP precursor, pro-opiomelanocortin (POMC). In this study we have extended our original findings by demonstrating the presence of messenger RNA for POMC by the use of a complementary DNA probe and Northern blot analysis of extracts of mouse and rat spleen. In addition, using high performance liquid chromatography (HPLC), we have shown that the major endorphin species in mouse spleen macrophages is beta-EP1-31, and that there are smaller amounts of each of the acetylated forms, N-acetyl-beta-EP1-16 (alpha-endorphin), N-acetyl-beta-EP1-17 (gamma-endorphin), N-acetyl-beta-EP1-27, and N-acetyl-beta-EP1-31. We interpret these studies as showing that (a) the spleen is an organ of POMC synthesis and that (b) the predominant COOH-terminal product of macrophage POMC is the opiate-receptor active species beta-EP1-31.

Animals↗
PubMed1977

Stimulation in vivo of the secretion of prolactin and growth hormone by beta-endorphin.

Morphine sulfate (MS) and the opioid peptide beta-endorphin beta-LPH-(61-91) stimulate prolactin and growth hormone release in steroid-primed and non-treated male rats when injected intravenously or intracisternally. On a molar basis beta-endorphin is at least 20 times more potent than MS, whereas Met5-enkephalin (beta-LPH-(61-65)) and alpha-endorphin (beta-LPH-(61-76)) are devoid of activity at the dose injected (300 mug). The in vivo stimulatory effects of beta-endorphin on prolactin secretion are reversed by the opiate antagonist naloxone. The absence of in vitro effect of MS and beta-endorphin on prolactin and growth hormone secretion by cultured rat pituitary cells suggest that they have a central nervous system site of action.

Animals↗
PubMed1992

Effects of opioid peptides on the tumoricidal activity of spleen cells from nude mice with or without tumors.

The present study was designed to explore the effects of opioid peptides on the immune systems of intact nude mice and nude mice bearing human ovarian cancer cells (KF). When spleen cells from intact nude mice were incubated with medium alone, a significant ability of spleen cells to lyse the KF cells was not observed. However, incubation of the spleen cells with 1 microM beta-endorphin or 1 microM alpha-endorphin induced a significant lytic activity on the KF cells. The control-level lytic activity was increased significantly to about 4.5-fold by 1 microM beta-endorphin and about 3.7-fold by 10 microM met-enkephalin. These results suggest that opioid peptides play a crucial role in cellular immunity. Thus, we examined plasma levels of beta-endorphin in patients with ovarian or uterine carcinoma. The plasma beta-endorphin levels in patients with ovarian or uterine carcinoma were significantly higher (more than twofold) than those of age-matched healthy women.

Adult↗
PubMed1979

Synthesis and secretion of corticotropins, melanotropins, and endorphins by rat intermediate pituitary cells.

The synthesis and secretion of various intermediate pituitary proteins was studied by using dispersed intermediate pituitary cell suspensions. Control studies indicated that the isolated cells were obtained in good yield and that after more than 24 h in culture the isolated cells continued to synthesize a collection of proteins similar to those found in freshly extracted intermediate pituitary tissue. Rat intermediate pituitary cells synthesized a molecule (Mr = 30,000; called 30K) that contained antigenic determinants for beta-endorphin, gamma-lipotropin, corticotropin (ACTH), and 16K fragment (the NH2-terminal region of mouse tumor cell pro-ACTH/endorphin). This 30K molecule, two high molecular weight forms of ACTH(13K and 20K), and 16K fragment were all shown to be glycoproteins. Continuous labeling and pulse-chase incubations were used to define the intracellular biosynthetic processing of the 30K molecule. After a 15-min pulse incubation the 30K molecule was the only labeled protein containing antigenic determinants for beta-endorphin, gamma-lipotropin, ACTH, or 16K fragment. A beta-lipotropin-like molecule served as a biosynthetic intermediate in the production of proteins similar to beta-endorphin and gamma-lipotropin. Methionine-enkephalin and alpha-endorphin were not major products in the intermediate lobe cells. Molecules similar to alpha-melanocyte-stimulating hormone and corticotropin-like intermediate lobe peptide (ACTH(18-39)) were also derived from the same 30K molecule; 20K ACTH served as a biosynthetic intermediate in this conversion. In rat intermediate pituitary cells ACTH(1-39) was not a major final product of the intracellular biosynthetic processing of the 30K molecule. The 30K molecule also served as a precursor to a protein similar to mouse tumor cell 16K fragment and related smaller proteins. With rat intermediate pituitary cells, pulse-chase experiments utilizing [35S]methionine demonstrated almost quantitative conversion of the 30K precursor into labeled proteins similar to beta-endorphin and alpha-melanocyte-stimulating hormone. In the absence of added secretagogues, small amounts of all of the smaller proteins derived from the 30K precursor were secreted coordinately into the culture medium.

Adrenocorticotropic Hormone↗
PubMed1985

A complete regulatory loop between the immune and neuroendocrine systems.

Infection of lymphocytes with Newcastle disease virus induces the cells to synthesize immunoreactive (ir) adrenocorticotropin (ACTH) and endorphins. The irACTH is synthesized de novo, and common properties of lymphocyte and pituitary ACTH include: antigenicity, bioactivity, molecular weight, and retention time on reverse phase high-pressure liquid chromatography. The irACTH appears to be active in vivo because a rise in serum corticosterone levels in hypophysectomized mice corresponds with spleen cell production of irACTH. Furthermore, preliminary experiments showed that B cell depletion blocked the normal rise in serum corticosterone levels after herpes simplex virus infection of intact mice. It seems that a similar system operates in vivo in humans. Typhoid vaccine, which induces lymphocyte-derived irACTH production in vitro, caused a time-dependent increase in the number of irACTH-positive lymphocytes in both hypopituitarism and normal short children. A rise in serum cortisol levels was seen in one patient with hypopituitarism and all normal patients. The above regulatory circuit also seems able to act in the reverse direction. Pituitary ACTH and alpha-endorphin can behave like lymphokines by being immunosuppressive at 0.5 microM in an in vitro antibody synthesis system. Further, lymphocytes were shown to have high-affinity receptors for both of these hormones. Thus, it appears that the immune and neuroendocrine systems have the ability to signal each other through common or related peptide hormones and receptors.

Adrenocorticotropic Hormone↗
PubMed1985

Modulation of macrophage-mediated tumoricidal activity by neuropeptides and neurohormones.

Recent evidence has suggested that stress may suppress the immune system and increase the frequency and severity of viral and neoplastic disease. The mechanisms for stress-induced modulation of immune function are unclear, but several neuropeptides are thought to be involved. Because macrophages play an important role in the host defense against infection and neoplasia, several stress-related neuropeptides were screened in efforts to determine whether these substances affect macrophage-mediated tumoricidal activity. Adrenocorticotropin and noradrenaline each completely blocked the capacity of mouse recombinant interferon-gamma (INF-gamma) to activate murine peritoneal macrophages to a tumoricidal state as measured by the lysis of 125I-UdR-labeled melanoma target cells. Vasoactive intestinal peptide significantly potentiated the suppressive effects of noradrenaline. In contrast, neurotensin markedly enhanced the cytolytic capability of peritoneal macrophages activated with INF-gamma. Several other neuropeptides, including substance P, alpha-endorphin, beta-endorphin, Leu-enkephalin, and Met-enkephalin, had no effect on macrophage activation. These findings demonstrate that selected stress-related neuropeptides and neurohormones significantly modulate the capacity of macrophages to attain a tumoricidal state and suggest that alteration of macrophage function by neuropeptides may be a prominent feature of stress-induced enhancement of neoplastic disease.

Adjuvants, Immunologic↗
PubMed1985

Identification of N alpha-acetyl-alpha-endorphin and N alpha-acetyl-gamma-endorphin isolated from the neurointermediate lobe of the rat pituitary gland.

The peptides that represent the major components with alpha-endorphin- and gamma-endorphin-like immunoreactivity in the rat neurointermediate lobe were purified to homogeneity and chemically characterized. Rat neurointermediate lobes were extracted by boiling and homogenization in acetic acid. Peptide purification was based on gel filtration, followed by two high-pressure liquid chromatography steps. Pools containing peptides with the size and immunochemical properties of alpha- and gamma-endorphins were resolved by reverse-phase high-pressure liquid chromatography into multiple immunoreactive components. The major forms were finally purified by paired-ion high-pressure liquid chromatography. The amino acid compositions of these peptides fitted the beta-endorphin sequences 1-16 and 1-17. Tryptic mapping, aminopeptidase M digestion, chromatographic characterization, and immunoreactivity to an antiserum recognizing the N alpha-acetylated terminus of endorphins showed that these peptides were indistinguishable from N alpha-acetyl-alpha-endorphin (N alpha-acetyl-beta-endorphin 1-16), and N alpha-acetyl-gamma-endorphin (N alpha-acetyl-beta-endorphin 1-17). The NH2-terminal residue of the peptides was identified by mass spectrometry as N alpha-acetyltyrosine, substantiating the identity of the peptides. The results demonstrate the existence of N alpha-acetylated alpha- and gamma-endorphin as endogenous peptides in the neurointermediate lobe of the rat pituitary gland. In view of their occurrence and biological properties they should be considered significant members of the pro-opiomelanocortin family.

Amino Acids↗
PubMed1985

Monoclonal antibody to enkephalins with binding characteristics similar to opiate receptor.

Monoclonal antibodies to enkephalins were established by immunization of mice with met-enkephalin, leu-enkephalin or both. Twenty-three clones with a high titer were classified into 6 types according to the binding properties to enkephalins and their derivatives. Antibody LM 239 showed binding characteristics similar to opiate receptor. It has a very high affinity to enkephalins and their derivatives which have a potent opioid activity, but a low affinity to enkephalin derivatives which devoid of opioid activity. The binding of 3H-met-enkephalin to the antibody was inhibited by naloxone and morphine, although the ID50 values were considerably higher than the Ka values of the alkaloids to opiate receptor.

Animals↗
PubMed1988

Increased concentration of alpha- and gamma-endorphin in post mortem hypothalamic tissue of schizophrenic patients.

The concentrations of alpha-, beta- and gamma-endorphin were determined by radioimmunoassay in HPLC fractionated extracts of post mortem hypothalamic tissue obtained from schizophrenic patients and controls. The hypothalamic concentration of alpha- and gamma-endorphin was significantly higher in patients than in controls (+72.9% and +50.5% respectively). No difference was found in the concentration of beta-endorphin, the putative precursor of alpha- and gamma-endorphins. These results suggest a deviant metabolism of beta-endorphin in the brain of schizophrenic patients. Whether this phenomenon is related to the psychopathology, or is a consequence of ante mortem farmacotherapy, remains to be established.

Adult↗
PubMed1985

High-performance liquid chromatographic analysis of in vitro central neuropeptide processing.

Reversed-phase high-performance liquid chromatography (HPLC) was used to study and characterize the in vitro proteolytic processing of beta-endorphin by twice-washed membrane homogenates. A high-resolution method, capable of separating over 30 different human beta-endorphin-related fragments in a single analysis, was used to study the time course of production of specific, biologically active endorphin fragments by membrane-associated proteases. The results demonstrate that frozen (-37 degrees C), postmortem human and rat brains are viable for processing studies and that metabolism proceeds similarly to that in fresh brain homogenates or slices. Significant differences were noted in the formation rates of putative neuroleptic peptides between sex- and age-matched postmortem brain tissues from controls versus postmortem brain tissues from neuropsychiatric patients or drug-treated animals. These data suggest that using HPLC to characterize neuropeptide processing in human or rat membrane-associated enzyme homogenates is both descriptive and quantitative and offers insight into the central regulation of neuropeptide metabolism.

Amino Acid Sequence↗
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↗
PubMed1985

[Distribution of alpha-, beta- and gamma-endorphins in the forebrain and diencephalon of the rat brain (immunohistochemical study)].

The investigation performed by means of specific rabbit antisera is one of the stages for mapping peptides. This is necessary for revealing functional role of the endorphins in the CNS. The indirect method of Coons is applied in parallel series of frontal paraffin slices of the brain 10 mcm thick. Neurons containing alpha-, beta- and gamma-endorphins are localized in the same brain areas. These are structures of the palaeocortex (the prepiriform cortex and the diagonal area) and those of the hypothalamus (the supraoptic, arcuate, ventromedial, mammillary nuclei, anterior and posterior fields). Endorphinergic neural fibers run within composition of various conducting cerebral systems, such as the corpus collosum, fornix, internal and external capsules.

Animals↗
PubMed1985

[Bronchial asthma and endorphins].

The paper deals with the investigation of endorphin content in the blood of patients with asthma. The increase in alpha- and beta-endorphin concentration was shown to depend on the severity of clinical manifestations of infectious-allergic and atopic forms of bronchial asthma. This regularity was not observed for gamma-endorphin. The infectious-allergic form of asthma was characterized by drastic reduction in the content of all three endorphin types upon treatment with dexamethasone. The possible role of endorphin reactions in the pathogenesis of asthma is discussed.

Adolescent↗
PubMedDate not supplied

[Radioimmunological assay of plasma levels of alpha-gamma-endorphins in healthy donors and patients with endogenous depression].

Radioimmunological procedure enabled to estimate alpha- and gamma-endorphins in human blood plasma without pre-extraction. Basal level of these neuropeptides in peripheric blood plasma of 18 healthy donors constituted: C alpha = 392 +/- 244 pg/ml and C gamma = 20.6 +/- 9.1 pg/ml. Content of these endorphins in blood plasma did not depend on age and sex. Concentration of alpha- and gamma-endorphins were shown to correlate in peripheric blood (r = 0.88); this suggests the overall mechanisms for regulation of their synthesis, secretion and degradation. At the same time, distinct differences in concentrations of alpha- and gamma-endorphins in blood plasma were not found in groups of healthy donors and of patients with endogenous psychoses and pronounced depressive symptoms.

Adolescent↗
PubMed1989

[A decrease in the content of immunoreactive alpha- and gamma-endorphins in the blood and the suppression of their hypersecretion under the influence of dexamethasone in emotional stress in monkeys].

Daily administration of 12 mg of dexamethasone to monkeys during 10 days resulted in decrease of the levels of alpha- and gamma-endorphins and cortisol 7 days after the first injection. The titers of these peptides in plasma of monkeys. exposed to two hours of immobilization stress were elevated twice above basal levels. The maximum elevation took place 6 hours after the beginning of immobilization. This effect wasn't detected in monkeys, which received 12 mg of dexamethasone during 10 days.

Acute Disease↗