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

The melanosome dispersing activity of prostaglandins PGE1, PGE2, PGF1 alpha, PGF2 alpha, PGI2 and 6 beta PGI, was tested on the melanophores of Anolis carolinensis. Only PGE2 and PGE1 were active and while PGE2 was the most potent and acted synergistically with alpha-MSH, PGE1 was additive with alpha-MSH. Arachidonic acid also stimulated melanosome dispersion but its effect was blocked by indomethacin suggesting an action through its conversion to PGE1 or PGE2. The effect of alpha-MSH, on the other hand, was unaltered by indomethacin which suggests that alpha-MSH stimulated melanosome dispersion does not depend upon prostaglandin synthesis. Thus, while some prostaglandins may interact with alpha-MSH to stimulate melanosome dispersion they are unlikely to mediate its action.
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PMID:The stimulatory effects of prostaglandins on the melanophores of the lizard, Anolis carolinensis. 391 35

This study was performed to examine an involvement of adenohypophysial arachidonic acid metabolites in the local mechanisms controlling the release of peptide hormones from the corticotrope cells of the anterior pituitary gland. Therefore, we investigated the effect of blockers of the lipoxygenase (nordihydroguaiaretic acid, NDGA), cyclooxygenase (indomethacin) or both of these enzyme systems (BW755C; eicosatetraynoic acid, ETYA) on the release of beta-endorphin-like (beta-E-IR) and adrenocorticotropin-like immunoreactivity (ACTH-IR) from rat anterior pituitary quarters incubated in vitro. NDGA and ETYA did not influence the basal release of beta-E- and ACTH-IR. However, upon stimulation by arginine-vasopressin (AVP) or synthetic ovine corticotropin-releasing factor (CRF(1-41], NDGA inhibited beta-E-IR release by 40%. ETYA inhibited AVP-induced release of beta-E- and ACTH-IR by 75%. Indomethacin and BW755C (lower concentration) enhanced beta-E-IR release, induced by AVP, by about 100%, whereas BW755C (higher concentration) had no effect. When indomethacin was present, NDGA, ETYA and BW755C (higher concentration) inhibited AVP-induced release of beta-E- and ACTH-IR. Prostaglandin E2 (PGE2) inhibited beta-E-IR release in response to AVP but failed to do so in the presence of NDGA. 12-OH-5,8,10,14-eicosatetraenoic acid (12-HETE) had no effect. When anterior pituitary quarters were incubated with 3H-arachidonic acid (3H-AA), NDGA and BW755C (higher concentration) but not indomethacin and BW755C (lower concentration) blocked the formation of a metabolite which co-migrated with 12-HETE on thin-layer chromatography.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Beta-endorphin and adrenocorticotropin release from rat adenohypophysis in vitro: evidence for local modulation by arachidonic acid metabolites of the cyclooxygenase and lipoxygenase pathway. 609 88

The pituitary mechanism of the central inhibitory effect of PGE2 on gastric secretion was investigated in rats. The intravenous (i.v.) injection of neurointermediate lobe extracts but not of anterior lobe extracts inhibited gastric secretion in pylorus-ligated rats. The i.c.v. administration of 3 micrograms of PGE2 increased the plasma level of vasopressin but had no effect on plasma beta-endorphin/beta-lipotropin. The i.v. administration of 10 micrograms d(CH2)5Tyr(Me) AVP, a vasopressin antagonist, prevented the inhibition of gastric secretion induced by i.c.v. administration of 3 micrograms PGE2 to pylorus-ligated rats. The results indicate that the central antisecretory action of PGE2 is due to the release of vasopressin from the pituitary gland.
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PMID:Centrally administered PGE2 inhibits gastric secretion in the rat by releasing vasopressin. 609 7

A disruption of the blood-aqueous barrier in rabbit eyes was elicited by use of topical prostaglandin E2(PGE2), infrared irradiation of the iris, or by subcutaneous alpha-melanocyte-stimulating hormone (alpha-MSH). The aqueous flare provoked was measured quantitatively with a photoelectric instrument. The effect of the (topical) beta-adrenergic antagonist timolol maleate on the breakdown of the blood-aqueous barrier was tested. Timolol applied topically in very large doses had no effect on exogenously administered PGE2. However, even in a very small concentration applied topically, timolol reduced the flare response to both infrared irradiation and alpha-MSH. These results support the theory that the effect of alpha-MSH and infrared irradiation on the blood-aqueous barrier is dependent on intact beta-adrenergic receptor sites.
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PMID:The effect of timolol maleate on the disruption of the blood-aqueous barrier in the rabbit eye. 611 20

Due to asymmetry of brain neurotransmitters and differential hemispheric information processing modes, it is suggested that the excessive use of one information processing mode could engender a state of brain reactivity whose neurochemical correlates would be either a rise in melatonin or beta-endorphin in systemic circulation. Since melatonin and beta-endorphin have opposite effects on lung-mediated regulation of prostaglandins, it is further suggested that the pulmonary inactivation of prostaglandin E1 would either be increased or inhibited. Low levels of PGE1 would engender high levels of PGE2 whose effects would explain the findings in schizophrenics of: 'reducing' pattern of visual evoked response, cerebral atrophy, and viral and autoimmune phenomena. The primacy of the disordered cognitive style in leading up to the immunological, biochemical and neuropathological processes is stressed. Implications of this model for understanding depression, anxiety and phobic disorders, autism, attention deficit disorder, obesity, alcoholism, smoking, drug addiction, sexual deviations, and certain psychosomatic and psychophysiological disorders are suggested.
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PMID:How information processing mode could affect prostaglandin E1 metabolism and lung inactivation: relevance of hemispheric specialization, neurotransmitter asymmetry and brain reactivity. 614 17

The present study examined the involvement of prostaglandins (PGs) in the mechanisms of ACTH and beta-endorphin release from rat anterior pituitary quarters incubated in vitro. Various cyclooxygenase inhibitors (indomethacin, diclofenac, flurbiprofen) had no effect on basal release of ACTH-like or beta-endorphin-like immunoreactivity (beta-EI), but enhanced ACTH-immunoreactivity/beta-EI release upon stimulation by arginine-vasopressin (AVP) or synthetic ovine corticotropin-releasing factor [CRF-(1-41)]. The lowest effective concentration of indomethacin was just sufficient to prevent PG synthesis. Indomethacin was similarly active after blockade of the phosphodiesterase by 3-isobutyl-1-methylxanthine. When added to the incubation media in concentrations up to 1 microM, PGE2, D2, F2 alpha, or prostacyclin (PGI2) did not alter basal beta-EI release; however, with stimulation by AVP or CRF-(1-41), PGE2 but not PGD2, F2 alpha, or I2 inhibited beta-EI release by about 60%. The concentrations of PGE2 in the incubation media, as measured by RIA, were somewhat higher than those of any other cyclooxygenase product (PGD2, F2 alpha, 6-keto-PGF1 alpha, thromboxane B2). Upon stimulation by AVP or CRF-(1-41), the concentrations of PGE2 increased, whereas those of PGD2 or F2 alpha remained unchanged. The release of beta-EI stimulated by high potassium concentration was not enhanced by indomethacin, although this release was sensitive to inhibition by PGE2. We conclude that PGE2 is formed locally subsequent to binding of the neurohormones and may act as a negative feedback-modulator of vasopressin's and CRF-(1-41)'s activity in the anterior pituitary gland.
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PMID:Adrenocorticotropin and beta-endorphin release from rat adenohypophysis in vitro: inhibition by prostaglandin E2 formed locally in response to vasopressin and corticotropin-releasing factor. 620 54

Prostaglandin E2 (PGE2) is present in fetal sheep and stimulates adrenal steroidogenesis in the fetal and newborn sheep. We have examined the site of this prostaglandin effect and the changes in adrenal responsiveness to exogenous PGE2 and adrenocorticotropic hormone (ACTH) in in vivo studies with newborn lambs. A bolus injection of PGE2 (50 micrograms) into the brachiocephalic trunk or descending aorta raised plasma cortisol (F) 25.3 +/- 4.5 (SE) ng/ml to 75.5 +/- 5.4 ng/ml at 15 to 30 minutes and 23.2 +/- 3.0 to 60.5 +/- 7.1 ng/ml at 15 to 30 minutes, respectively (both P less than 0.001). Intra-aortic infusion of PGE2 (1.25 micrograms/ml) produced a similar significant rise in F. Basal plasma F decreased from 34.3 +/- 7.4 ng/ml at 9 to 11 days to 14.1 +/- 4.0 ng/ml at 12 to 13 days and 18.2 +/- 5.7 ng/ml at 17 to 18 days. Peak F during a 60-minute PGE2 infusion was significantly greater at 9 to 11 days (127.3 +/- 14.6 ng/ml) than at the two later times (57.2 +/- 7.07 and 55.7 +/- 14.6 ng/ml, respectively, both P less than 0.01). The response to ACTH was greater 24 hours after birth than at 7 or 28 days of age. Injection of ACTH or alpha-melanocyte-stimulating hormone during an intra-aortic PGE2 infusion did not further elevate plasma F over the rise seen with PGE2 alone. The results suggest both direct and indirect stimulatory effects of PGE2 on adrenal function in newborn sheep, and are consistent with a role of endogenous PGE2 as an intermediate factor in ACTH action.
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PMID:Adrenal responses to prostaglandin E2 in newborn lambs. 625 35

ACTH (1--24) and alpha-melanotropin (alpha-MSH), peptides previously shown to influence body temperature when administered centrally and to occur naturally in brain regions important to temperature control, were injected intracerebroventricularly (ICV) in rabbits. The peptides in doses of 1.25, 2.5 and 5.0 micrograms produced dose-related hypothermias in a 23 degrees C environment, and greater decreases in body temperature when the experiments were repeated in the cold (10 degrees C), but the largest dose had no effect on temperature in the heat (30 degrees C). These results indicate that the peptides do not reduce the central set-point of temperature control. Rather, they appear to selectively inhibit heat conservation and production responses. Five microgram of ACTH reversed vasoconstriction and inhibited rises in temperature caused by leukocytic pyrogen (LP) given IV and ICV. The same dose of alpha-MSH also reduced fever produced by IV and ICV LP, but the reduction was not as great as after ACTH. Both peptides (5 micrograms) also reduced temperature rises and vasoconstriction caused by ICV PGE2. ACTH reduced d-amphetamine-induced hyperthermia without altering vasoconstriction which suggests that this peptide can reduce temperature rises by inhibiting heat production alone. One of the most important findings was that the peptides are antipyretic in that they reduce fever at doses (0.25 microgram, ICV) that do not affect normal temperature. The powerful effects of these peptides on resting body temperature, hyperthermia and fever, together with their presence in brain tissue important to temperature control, suggest that the endogenous central peptides participate in thermoregulation, perhaps by limiting fever and influencing normal temperature.
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PMID:Hypothermic and antipyretic effects of centrally administered ACTH (1--24) and alpha-melanotropin. 627 Jun 34

A possible direct effect of prostaglandins on alpha-melanotropin (alpha-MSH) release at the level of the intermediate lobe of the frog pituitary was investigated in vitro using a perifusion system technique. The effect of prostaglandins was studied on both spontaneous and TRH-stimulated alpha-MSH secretion. No significant effect of PGE1, PGE2, PGF1 alpha or PGF2 alpha on basal release of alpha-MSH could be detected. Indomethacin did not alter the alpha-MSH release induced by TRH. Conversely a significant increase in TRH-induced alpha-MSH secretion was observed in the presence of 1 x 10(-6) M PGE1. This magnifying effect was directly related to the concentration of TRH for doses ranging from 1 x 10(-8) M to 1 x 10(-6) M.
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PMID:Stimulatory effect of prostaglandin E1 on thyroliberin-induced alpha-melanotropin release from perifused neuro-intermediate lobes of frog pituitary gland. 678 3

Intracerebroventricular administration of prototype non-peptide opioid receptor (mu, kappa, sigma) agonists, morphine, ketocyclazocine and N-allyl normetazocine (SKF 10,047) and an agonist at both kappa and sigma receptors, pentazocine, induced hyperthermia in guinea-pigs. Similar administration of peptide opioids like beta-endorphin (BE), methionine enkephalin (Met-E), leucine enkephalin (Leu-E) and their synthetic analogues D-ala2-methionine-enkephalinamide (D-ala2-Met-E) and D-ala2-leucine-enkephalinamide (D-ala2-Leu-E) also caused hyperthermia. Of the three anion transport systems (iodide, hippurate and liver-like) present in the choroid plexus, only the liver-like transport system seems to be important to central inactivation of beta-endorphin, D-ala2-Met-enkephalin and D-ala2-Leu-enkephalin since iodipamide (an inhibitor of the liver-like transport system) augmented the hyperthermia. Prostaglandins (PG) and norepinephrine (NE) were not involved in peptide- and non-peptide opioid-induced hyperthermia because a prostaglandin synthesis inhibitor, indomethacin, and an alpha-adrenergic receptor blocker, phenoxybenzamine, had no thermolytic effect. Likewise cAMP was not required since a phosphodiesterase inhibitor, theophylline, did not accentuate the hyperthermia due to administration of peptide and non-peptide opioids. Naloxone-sensitive receptors were involved in the induction of hyperthermia by morphine and beta-endorphin since naloxone attenuated the effect. In contrast, the hyperthermic responses to ketocyclazocine, SKF 10,047, pentazocine, Met-enkephalin, Leu-enkephalin, D-ala2-Met-enkephalin and D-ala2-Leu-enkephalin were not antagonized by naloxone. Lack of antagonism of naloxone on pyrogen, arachidonic acid, PGE2, dibutyryl cAMP and NE-induced hyperthermia indicates that endogenous opioid peptides are not likely to be central mediators of the hyperthermia induced by these agents.
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PMID:Hyperthermic responses to central injections of some peptide and non-peptide opioids in the guinea-pig. 687 39


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