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Results for “alpha-Endorphin”

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At least 163 records · Page 9Linked to original sources
PubMed1986

In vitro effects of endogenous opiate peptides on thyrotropin function: inhibition of thyrotropin-releasing hormone release and absence of effect on thyrotropin release.

Thyrotropin-releasing hormone (TRH) or thyroid-stimulating hormone (TSH) was measured by radioimmunoassay in the incubation medium of rat hypothalami or anterior pituitary halves, respectively. We studied the effect of opioid peptide addition (10(-8) to 10(-6) M) on TRH or TSH release. alpha- or beta-Endorphin decreased TRH release in a dose-dependent manner while only 10(-6) M Leu- or Met-enkephalin decreased TRH release. These inhibitory effects were prevented by addition of naloxone (10(-5) M). In the dose range used none of the opioid peptides modified TSH release. These results indicate that opioid peptides may play a role in the regulation of thyrotropin secretion via a hypothalamic action on TRH release.

Animals↗
PubMed1987

Differential effects of beta-endorphin fragments on human natural killing.

The endogenous opiate peptide, beta-endorphin, has two effects on human natural killing (NK). Preincubation of effector lymphocytes with between 10(-7) and 10(-11) M beta-endorphin increases NK. Preincubation with lower concentrations results in a reduction in NK. Endorphin peptides containing an unmodified N-terminal sequence, and which are known to bind only to opiate receptors, increase NK. Sequences reported to bind only to nonopiate receptors reduce NK.

Cytotoxicity, Immunologic↗
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↗
PubMed1981

Rapid separation of enkephalins and endorphins on Sep-Pak reverse phase cartridges.

A simple, rapid method is described for separating neuropeptides. Samples were injected on Sep-Pak disposable reverse phase cartridges and eluted with a step gradient of n-propanol in formate-pyridine buffer. Enkephalins are separated from metabolic products. Separation alpha, beta and gamma-endorphin demonstrated, and Met- and Leu-enkephalin are also separated. This inexpensive, reproducible method a useful in studies of neuropeptide metabolism, purification of synthesized peptides, separation prior to RIA, or concentration of neuropeptides.

Chromatography↗
PubMed1983

Application of ELISA for assessment of antiserum immunoreactivity in endocrine immunocytochemical studies.

An indirect method of an enzyme-linked immunosorbent assay (ELISA) is described to assess the reactivity of antisera used for the identification of peptide hormone producing cells by immunocytochemistry. Compared with radioimmunoassay and immunodiffusion, the ELISA method has the advantages of simplicity and sensitivity and represents with the hormone adsorbed to a matrix a situation more or less comparable to that in tissue sections. It is concluded that specificity testing of antisera applied in endocrine immunocytochemical studies can best be achieved by application of the ELISA method in combination with appropriate tissue controls.

Adrenocorticotropic Hormone↗
PubMed1983

Secretion of pro-opiocortin peptides from isolated perfused rat pars intermedia cells.

The perfused, isolated, pituitary cell column was used to measure the release of alpha-melanotropin (alpha-MSH)-like immunoreactivity (LI), carboxyl terminal corticotropin (C-ACTH)-LI, gamma-lipotropin (gamma-LPH)-LI, alpha-endorphin-LI, beta-endorphin-LI and amino-terminal pro-opiocortin (N-POC)-LI from rat pars intermedia (PI) cells. Concomitant secretion of all PI peptides was observed during basal release and in response to all applied stimuli. Dopamine (DA) caused a dose-dependent (10(-9)-10(-5) M) simultaneous inhibition of peptide release which was antagonised by haloperidol. Isoprenaline stimulated the release of PI peptides in a parallel, dose-related (10(-10)-10(-6) M) manner and was blocked by propranolol. Stimulation of peptide secretion caused by low concentrations (10(-8) M), of adrenaline (AD) and noradrenaline (NA) changed to inhibition at high concentrations (10(-5) M) whereas intermediate concentrations (10(-6), 10(-7) M) possessed both inhibitory and excitatory effects. A 45 mM solution of K+ ions stimulated the release of PI peptides and both the K+-stimulated secretion and basal secretion were Ca++-dependent. MSH-release-inhibiting factor (MIF) and 5-hydroxytryptamine (5-HT) failed to alter peptide secretion from the perfused PI cells. We conclude that pro-opiocortin (POC) peptides are released concomitantly from rat PI cells and that biogenic amines are involved in their release.

Adrenocorticotropic Hormone↗
PubMed1982

Neuropeptides and cerebrospinal fluid.

Neuropeptides are present in brain tissue as well as in cerebrospinal fluid. Studies from a variety of disciplines have demonstrated that neuropeptides have neuromodulatory activities. Such activities are apparent in the involvement of neuropeptides in the regulation of adaptive, autonomic, and endocrine functions of the brain. Neuropeptides exert their neuromodulating influences by acting as neurotransmitters or as neurohormones. The neurotransmitter function of neuropeptides is associated with their synthesis in situ in brain and anatomical distribution via neuropeptidergic fibre systems. The presence of such neuropeptides in cerebrospinal fluid may be due primarily to drainage into the cerebrospinal fluid compartments, their levels being a reflection of cellular processes such as biosynthesis, release, and metabolism. On the other hand, neuropeptides functioning as neurohormones may be actively delivered into the cerebrospinal fluid from central or peripheral sources. They employ the pathways of cerebrospinal fluid circulation as avenues of transport, and their cerebrospinal fluid levels may be functionally related to neurohormonal activity. In either case the cerebrospinal fluid levels are informative on the neuropeptide climate in brain; thus their determination is meaningful. The methodology for the sensitive and specific determination of neuropeptides is becoming available. Determination of neuropeptides may well be of diagnostic value in clinical practice.

Adrenocorticotropic Hormone↗
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↗