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)

Pimozide, a specific blocker of dopaminergic receptors, was injected for 4 or 9 days in freshwater (FW) eels or eels acclimated to sea water (SW) for 10 or 30 days. The daily dose was 100 or 200 microgram/100 g. Melanophore index values increase in FW and in 1 month-SW injected eels. All the treated fish react by a total or subtotal degranulation of the lead-hematoxylin positive cells in the pars intermedia. These cells were previously identified as alpha-MSH-secreting cells. The MSH cell nuclear area is significantly increased, nucleoli are larger and the endoplasmic reticulum more developed. The intensity of the response is similar in FW and SW eels, but it does not increase with the higher dose. The rapid release of pituitary alpha-MSH is also visualized by immunofluorescence and immunoenzymologic techniques. No effect on the second cell type of the pars intermedia (PAS-positive cell) is detected. The amount of neurosecretory material is often reduced in the neurohypophysis. These results suggest that the hypothalamic inhibitory control of MSH release and synthesis is mediated through dopaminergic fibers in the eel, but other factors cannot be ignored in this regulation.
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PMID:Effect of pimozide on the cytology of the eel pituitary. II. MSH-secreting cells. 65 40

The effects of cocaine on rat plasma and brain alpha-melanocyte-stimulating hormone (alpha-MSH) levels have been studied by means of a specific radioimmunoassay. The selected brain areas were the hypothalamus, septum-nucleus accumbens and hippocampus. Cocaine given subcutaneously decreased the alpha-MSH levels in the peripheral blood. Pimozide, a dopaminergic antagonist, had an opposite effect: it increased the alpha-MSH levels in the peripheral blood. Combined treatment with cocaine + pimozide resulted in a decrease in the pimozide-induced increase in alpha-MSH levels in the blood. Cocaine and pimozide or the combination of cocaine + pimozide were ineffective on the alpha-MSH levels in the hypothalamus and septum-accumbens brain regions. In the hippocampus, cocaine in the dose applied induced a slight but not significant decrease in the alpha-MSH level. Pimozide caused a significant decrease in the hippocampal alpha-MSH level which disappeared at 60 min. Cocaine prevented the pimozide-induced depletion of alpha-MSH. The data indicate that cocaine may act as a dopaminergic agonist in the mechanism of control of alpha-MSH secretion from the intermediate lobe of the pituitary. The alpha-MSH levels in the brain are controlled by different mechanisms. In some brain areas, the dopaminergic system has no action; in others the mechanisms might be similar to but slightly different from that in the pituitary.
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PMID:Effects of cocaine and pimozide on plasma and brain alpha-melanocyte-stimulating hormone levels in rats. 131 8

In a group of adult Soay rams housed indoors under an artificial light cycle of alternating 16-week periods of long and short days, there was a conspicuous long-term cycle in the peripheral plasma concentrations of beta-endorphin and prolactin. The levels of beta-endorphin were highest under short days and lowest under long days (15-fold change), and inversely related to the changes in the plasma levels of prolactin (120-fold change). The role of dopamine in the control of beta-endorphin and prolactin was investigated in a series of experiments, conducted under both long and short days, in which rams were treated with dopamine receptor agonists (dopamine and bromocriptine) and antagonists (pimozide and sulpiride). Naloxone (opioid antagonist) was also administered to assess the additional involvement of endogenous opioids. Dopamine injected i.v. (6.6 mg/kg every 10 min) did not significantly affect the mean plasma concentrations of beta-endorphin and prolactin under either long or short days. Pimozide (0.08 mg/kg i.m. every 2 h) caused a large increase in the mean plasma concentrations of beta-endorphin and prolactin under long days but not short days. Naloxone (1.6 mg/kg, i.v.), administered alone or in combination with dopamine or pimozide, had no effect on the mean plasma concentrations of beta-endorphin and prolactin, except under short days when, combined with pimozide, it induced an increase in the plasma concentrations of the two polypeptides.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of the photoperiod-induced cycle in the peripheral blood concentrations of beta-endorphin and prolactin in the ram: role of dopamine and endogenous opioids. 228 Feb 12

To examine the regulation and functional significance of canine pituitary pars intermedia corticotrophs, ACTH and cortisol responses to CRF were studied in healthy dogs before and after treatment with dexamethasone. In addition the effects of the dopamine agonist bromocriptine and the dopamine antagonist pimozide were investigated. In the latter two instances prolactin concentrations were also measured. Finally the pituitaries were studied immunocytochemically for ACTH and alpha-MSH. No response of ACTH or cortisol to bromocriptine was observed. Pimozide caused a slight rise in ACTH levels in some dogs. However, prolactin levels significantly decreased with bromocriptine and increased with pimozide. Injection of synthetic ovine CRF to dogs was followed by sharp increases in ACTH and cortisol values. These responses were obliterated by prior treatment with dexamethasone. In 1 of 4 dogs given dexamethasone before euthanasia, there were few pars distalis cells with ACTH(1-24) immunopositivity, although persistence of ACTH(1-24) reaction was noted within cells of the pars intermedia. The results indicate that none of the CRF-induced ACTH secretion in dogs is derived from pars intermedia corticotrophs. Dosages of bromocriptine and pimozide that clearly alter prolactin secretion do not consistently affect ACTH levels.
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PMID:Some functional aspects of canine corticotrophs. 283 Nov 26