Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Light microscopic double immunocytochemical stainings, performed on sea bass hypothalamo-hypophysial sections, revealed the projection of different neuropeptide-immunoreactive neurons innervating the hormone-producing cell populations in the pituitary gland. In the rostral pars distalis (PD) the ACTH cells were found in close proximity to fibers immunoreactive for somatostatin (SRIF), growth hormone-releasing hormone (GRF), corticotropin-releasing hormone (CRF), vasotocin (VT), isotocin (IT), substance P (SP), neurotensin, and galanin (GAL), while the PRL cell zone seemed only innervated by nerve fibers immunopositive for GAL. In the proximal PD, fibers immunoreactive for SRIF, GRF, VT, IT, cholecystokinin, SP, neuropeptide Y, and GAL formed a close relationship with the growth hormone cells. The gonadotrophs were observed near nerve fibers immunostained for gonadotropin-releasing hormone, IT, and less obviously GRF and VT, while fibers positive for GRF, CRF, VT, IT, SP, and GAL penetrated between and formed a close association with the thyrotrophs. In the pars intermedia the MSH cells and the PAS-positive (PAS+) cells seemed both innervated by separate nerve fibers immunoreactive for GRF, CRF, melanin concentrating hormone, VT, IT, and SP. All these results suggest a functional role of the neuropeptides in the adenohypophysis of the sea bass, possibly in the synthesis and/or release of hypophysial hormones from the different cell types.
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PMID:Immunocytochemical demonstration of close relationships between neuropeptidergic nerve fibers and hormone-producing cell types in the adenohypophysis of the sea bass (Dicentrarchus labrax). 246 54

The dog pituitary pars intermedia (PI) appears to consist of relative large numbers of ACTH-containing cells in addition to the more abundant alpha MSH-containing cells. Since regulation of PI secretion probably varies across mammalian species, this study was undertaken to identify substances potentially involved in the control of dog PI POMC peptide secretion and to determine if these substances altered the secretion of immunoreactive (IR) ACTH and IR-alpha MSH in a parallel fashion. Pituitary neurointermediate lobes from dogs were collected and dispersed, and the PI cells obtained were perifused. For comparison, rat PI and pars distalis (PD) cells as well as dog PD cells were similarly collected and perifused. Dog PI cells secreted IR-alpha MSH at a basal rate of 125 +/- 59 (mean +/- SD) pg/min.10(5) cells and IR-ACTH at a rate of 40 +/- 9 pg/min.10(5) cells (molar IR-alpha MSH/IR-ACTH = 10). In contrast, secretion rates for IR-alpha MSH and IR-ACTH from perifused rat PI cells were 171 +/- 108 and 3 +/- 2 pg/min.10(5) cells, respectively (molar IR-alpha MSH/IR-ACTH = 179). Using Sephadex G-50 gel filtration chromatography, virtually all of the IR-beta-endorphin secreted by dog PI cells eluted near beta-endorphin (1-31). In addition, all of the IR-alpha MSH secreted by dog PI cells coeluted with synthetic alpha MSH on the G-50 column, but IR-ACTH appeared in two peaks, one eluting near porcine ACTH-(1-39) and another, apparently larger mol wt species. Dopamine and somatostatin were found to inhibit the secretion of IR-alpha MSH and IR-ACTH from perifused dog PI cells in a parallel and dose-dependent fashion. Norepinephrine and epinephrine similarly inhibited POMC peptide secretion, but this effect was blocked by haloperidol, suggesting that it was mediated through a dopamine receptor. CRF stimulated the secretion of both hormones from dog PI, and this effect was abolished by treatment of the cells with either dopamine or somatostatin. Cortisol had no effect on either basal or CRF-stimulated secretion of IR-alpha MSH or IR-ACTH from dog PI cells, but it did inhibit CRF-stimulated IR-ACTH from perifused dog PD. These results suggest that 1) dog PI secretes considerably more IR-ACTH than that in the rat; 2) the probable separate cell sources of IR-alpha MSH and IR-ACTH in dog PI are regulated in an identical fashion; and 3) dopamine, somatostatin, and CRF may function in the physiological or pathophysiological regulation of dog PI.
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PMID:Regulation and secretion of proopiomelanocortin peptides from isolated perifused dog pituitary pars intermedia cells. 253 71

Directional behavioral and functional asymmetries (i.e., left-biased or right-biased in all or most animals of the population) induced by certain chemical substances are new types of brain and spinal cord asymmetry. The revealed asymmetry comprises: (1) left- or right-biased circle rotation in rat, (2) hind limb postural asymmetry resulting from alteration of the left or right flexion reflex in rat and cat, and (3) asymmetric alterations of the evoked potentials (EP) in the turtle visual cortex. Circle rotation of animals is induced by hypothalamic neurohormones (somatostatin, LH-RH, substance P, and TRH). Postural asymmetry develops under the effect produced by enkephalins and opioid kappa- and delta-agonists, sigma-agonist SKF 10.047, Arg-vasopressin. Endogenous peptide factors, the activity (or content) of which increased under brain and spinal cord unilateral injury, as well as the ones localized in the left or right hemisphere, also induced postural asymmetry. EP of the left and right turtle visual cortex were inhibited by enkephalins and opioid kappa-, and delta- and mu-agonists, and factors predominantly localized in the left or right turtle visual cortex in a different manner. The data reported here suggest the existence of a side-specific mechanism for a selective neurohormonal regulation of the neuronal activity and other processes in the left and right halves of brain and spinal cord which involves lateralized neuropeptides and their receptors. This mechanism might serve to maintain a certain balance between the activity of the left and right-side neurons, and other contralateral processes in the paired and bilateral structures in brain and spinal cord. Significant deviations from the balance occur most likely due to powerful unilateral stimuli, e.g., unilateral trauma. Many neuropeptides (opioid ones, somatostatin, MSH, ACTH) are, presumably, involved in the regeneration processes in the central and peripheral nervous system. In the case of brain lesions, some lateralized endogenous peptides may participate in the regulation of regeneration process on the left, whereas the other ones, on the right side of the midline, which depends on the side of the lesion. Some lateralized receptors and ligands may serve as positional markers of the left, whereas the other ones may serve as those of the right brain hemisphere. In ontogenesis, these markers are probably necessary to perform the function of the mechanism responsible for symmetrical brain formation.
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PMID:Neuropeptides induce directional asymmetry in brain and spinal cord: facts and hypotheses. 268 85

A large number of antisera to regulatory vertebrate peptides was tested immunocytochemically on the nervous system of the Colorado potato beetle to further characterize the peptidergic cells of the neuro-endocrine system and to reveal cells participating in endocrine control mechanisms. Neurons, neurosecretory cells, axons and axon terminals were revealed by antisera to ACTH, gastrin, CCK, alpha-endorphin, beta-endorphin, gamma 1-MSH, insulin, motilin, human calcitonin, growth hormone, somatostatin, CRF, ovine prolactin and rat prolactin. Together with previously described results these findings demonstrate that at least 19 different peptidergic cell types are present in the Colorado potato beetle. Several of these cell types are identical with the known neurosecretory cells, while others have not been identified before. The functions of the immunoreactive neurons are as yet unclear, although in two cases the localization of these cells gives some clues. Thus the lateral neurosecretory cells, which are immunoreactive with antisera to beta-endorphin and ovine prolactin, may regulate corpus allatum activity, whereas a CRF immunoreactive substance seems to be used as neurotransmitter by antennal receptors. These immunocytochemical findings do not imply that the immunoreactive substances are evolutionarily related to the vertebrate peptides to which the antisera were raised. It is postulated that if the part of the substance recognized by a certain antiserum is functionally important for the insect, which should be so if the insect peptide is evolutionarily related to its vertebrate homologue, the antiserum should reveal homologous cells in different insect species. The consequence of this hypothesis is, that if an antiserum does not reveal homologous neurons in different insect species, the immunologically demonstrated substance is probably of little physiological importance, and will not be related evolutionarily to the vertebrate analogue. The positive immunocytochemical results in the Colorado potato beetle are discussed in relation to these considerations.
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PMID:Immunocytochemical localization of peptidergic neurons and neurosecretory cells in the neuro-endocrine system of the Colorado potato beetle with antisera to vertebrate regulatory peptides. 285 60

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.
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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

Previous results indicate that GH-releasing factor (GRF) induces a dose-related stimulation of somatostatin (SRIF) release from median eminence fragments incubated in vitro. In the present investigation we examined whether this action was mediated by other neurotransmitters or neuromodulators. Studies using receptor blockers for dopamine (pimozide), alpha-adrenergic receptors (phentolamine), and muscarinic cholinergic receptors (atropine) revealed that these receptor blockers, at a dose of 10(-6) M, which was capable of blocking the response to the relevant transmitter in previous studies, had no effect on basal release of SRIF in the static incubation system and failed to modify the response to GRF (10(-10) M). On the other hand, the opiate receptor blocker naloxone at a dose of 10(-6) M, although failing to alter basal release, completely blocked the response to 10(-10) M GRF. To determine the opioid peptide involved in mediating the SRIF release induced by GRF, highly specific antibodies directed against beta-endorphin were added to the in vitro incubation system. These antibodies significantly depressed basal release SRIF and completely blocked the response to 10(-10) M GRF. Incubations in the presence of normal rabbit serum or highly specific antiserum directed against alpha MSH had no effect on either basal release of SRIF or that induced by GRF. These results suggest that in this incubation system there is a beta-endorphin tone which is partially responsible for the basal release of SRIF and that the stimulation of SRIF release induced by GRF is mediated via beta-endorphin terminals, which presumably synapse on the terminals of the somatostatinergic neurons in the median eminence fragment.
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PMID:Evidence that growth hormone-releasing factor stimulates somatostatin release in vitro via beta-endorphin. 287 65

Previous studies have shown that intracisternal (i.c.), but not intravenous administration of thyrotropin-releasing hormone (TRH), an endogenous tripeptide (pGlu-His-Pro-NH2), produces a time-, dose-dependent and vagus-mediated stimulation of acid secretion in rats. This study was designed to test the hypothesis that endogenous brain TRH plays a role in regulation of acid secretion in the pylorus-ligation model. In confirmation of previous reports, i.c. TRH (1 microgram) significantly (P less than 0.01) stimulated gastric acid output, gastric secretory volume and decreased gastric intraluminal pH. Intracerebroventricular (i.c.v.) infusion of TRH antiserum (anti-TRH) 30 min prior to pyloric occlusion significantly reduced acid output, secretory volume and raised gastric pH. This inhibitory gastric acid secretory response to i.c.v. anti-TRH appears to be specific since i.c.v. infusion of normal rabbit serum or antisera raised against neurotensin (NT), Leu-enkephalin (L-enk), gonadotropin-releasing hormone (GnRH), somatostatin (SRIF) and alpha-melanocyte stimulating hormone (alpha-MSH) were without measurable effect. The findings of this study indicate that endogenous brain TRH, but not NT, L-enk, GnRH, SRIF or alpha-MSH plays a physiological role in regulation of acid secretion.
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PMID:Inhibition of gastric acid secretion by immunoneutralization of endogenous brain thyrotropin-releasing hormone. 288 Jun 45

The influence of alpha-melanocyte stimulating hormone (alpha-MSH) and beta-endorphin (beta-END) on the secretion of somatostatin (SRIF) from the median eminence (ME) was studied using an in vitro incubation system. The MEs from adult male rats were first preincubated at 37 degrees C for 30 min with constant shaking in 0.4 ml of Krebs-Ringer bicarbonate-glucose buffer (pH 7.4) containing bacitracin in an atmosphere of 95% O2/5% CO2. Medium was discarded and replaced by medium containing different doses of alpha-MSH, beta-END, or a fixed dose of alpha-MSH (10(-7) M or 10(-9) M) plus beta-END at various concentrations. By themselves alpha-MSH and beta-END did not alter basal SRIF release, but in the presence of alpha-MSH (10(-7) M) beta-END stimulated somatostatin release. This effect was significant at concentrations of beta-END of 10(-8) M and higher. The permissive effect of alpha-MSH was observed at a concentration as low as 10(-9) M, but in this case the stimulatory effect of beta-END became evident only at higher doses tested (10(-7) M). It is suggested that alpha-MSH and beta-END participate in the modulation of SRIF release. By themselves beta-END and alpha-MSH did not affect basal release of SRIF but in the presence of alpha-MSH, beta-END had a stimulatory effect on SRIF release. The mechanism for this interaction is unknown. The results are consistent with the possibility that beta-END neurons have stimulatory and inhibitory effects on SRIF release and that alpha-MSH, by blocking the inhibitory components, discloses the stimulatory effect of beta-END on SRIF release.
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PMID:Alpha-melanocyte stimulating hormone discloses a stimulatory effect of beta-endorphin on somatostatin release. 288 55

It is currently believed that Parkinson disease (PD) is due to a degenerative process that independently damages multiple areas of the central and peripheral nervous system. Loss of nigrostriatal dopamine is now widely recognized as being directly related to the motor symptoms in Parkinson's disease. Parkinsonian patients also exhibit symptoms and signs suggestive of hypothalamic dysfunction (e.g. dysautonomia, impaired heat tolerance). The latter clinical features are supported by pathological, biochemical and endocrinological findings. Lewy body formation has been demonstrated in every nucleus of the hypothalamus, specifically the tuberomamillary and posterior hypothalamic. Preferential involvement of the hypothalamus was also noted in patients after post-encephalitic parkinsonism. Loss of dopamine (30-40%) in the hypothalamus of affected patients has been shown in recent studies, and is compatible with the reported abnormalities of growth hormone release in response to L-dopa administration, elevated plasma levels of MSH, and reduced CSF levels of somatostatin and beta-endorphins in these patients. Deranged immunological mechanisms have been found in PD patients including the presence of autoantibodies against sympathetic ganglia neurons, adrenal medulla and caudate nucleus. On the evidence of on pathological studies demonstrating the early vulnerability of the hypothalamus in aging and PD, and the known role of the hypothalamus in immune modulation, we expect that it will be shown that primary damage of the hypothalamus leads to subsequent secondary degeneration of structures receiving direct projections from the hypothalamus. Within this framework, the dopaminergic systems may be damaged, since striatal dopamine synthesis and receptor sensitivity have been shown to be regulated by ACTH and alpha-MSH through direct arcuate nucleus-striatal projections.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The hypothalamus in Parkinson disease. 288 37

Astrocytes from cortex, cerebellum, and spinal cord responded to isoproterenol and vasoactive intestinal peptide (VIP) with increases in intracellular cyclic AMP levels. The response to VIP was as great as that to isoproterenol in cortical astrocytes (180-fold and 185-fold, respectively), and the effect of VIP in combination with isoproterenol was partially additive. Spinal cord astrocytes also responded to VIP and isoproterenol with equal potency (seven- to ninefold and eight- to 13-fold, respectively), but the level of response was much smaller than in cortex. Spinal cord astrocytes were synergistic in their response to VIP and isoproterenol. The response to VIP was lowest in cerebellar astrocytes (only threefold), and no additivity was observed when VIP was added together with isoproterenol. A small response to alpha-melanocyte stimulating hormone (alpha-MSH) was also observed in cortex and cerebellum, but not in spinal cord. Somatostatin inhibited the response to isoproterenol in cortex and cerebellum, but had no effect in spinal cord. The results from the above study show that astrocytes obtained from these three regions of the rat CNS express quite different responses to VIP and alpha-MSH and further point to possible astrocyte heterogeneity.
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PMID:Astrocytes from forebrain, cerebellum, and spinal cord differ in their responses to vasoactive intestinal peptide. 290 98


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