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)

One subpopulation of amacrine interneurons in the turtle retina was shown to contain met-enkephalin by means of immunocytochemistry, and another was demonstrated to have a high-affinity uptake system for [3H]-dopamine by means of autoradiography. Although the amacrine soma size, density, and distribution of their neurites in IPL substrata was similar in retinas in which met-enkephalin and dopamine were localized, combined light microscope immunocytochemistry-autoradiography demonstrated that these two neurotransmitter systems did not coexist in the same cells. Because the two amacrine cell subtypes ramify in the same IPL substrata, neuronal interaction between them is possible. Release experiments showed that the potassium-induced release of [3H]-dopamine from the superfused turtle retina was reduced by 40% when enkephalin was added to the superfusate. The inhibition of [3H]-dopamine release could be blocked by the addition of naloxone. The addition of enkephalin had no effect of the potassium-induced release of [3H]-GABA from the superfused retina. These findings suggest that an enkephalinergic modulation of the dopaminergic amacrine cell system exists in the turtle retina.
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PMID:Enkephalinergic modulation of the dopamine system in the turtle retina. 248 18

Beta-endorphin has been reported to regulate not only stress- and suckling-induced but also basal prolactin secretion. In the aim to better evaluate the endogenous beta-endorphin-prolactin interrelation, we measured beta-endorphin levels in a new rat strain, genetically hypoprolactinemic and characterized by a total lack of lactation: IPL nude rat. Beta-endorphin was measured using a specific anti-h-beta endorphin in plasma and extracts of anterior and neurointermediate lobes of the pituitary, hypothalamus and brain. Pituitary extracts were also chromatographed on Sephadex G50 column. Results obtained showed that in IPL nude females on diestrus and males, the beta-endorphin contents of the neurointermediate lobe was significantly lower than in normal rats, while the values found in the other organs and plasma were similar. However, elution pattern of the anterior pituitary extract from male rats showed greater immunoactivity eluting as I125 h-beta-endorphin than in normal rat; this was not the case for the female rat. These results are consistent with a differential regulation of beta-endorphin levels of anterior and neurointermediate lobe by catecholamines. Moreover they suggest that PRL secretion was more related to neurointermediate beta-endorphin.
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PMID:beta-Endorphin in genetically hypoprolactinemic rat: IPL nude rat. 293 1

IPL nude females present an absence of lactation with hypoprolactinemia. While males present a slight but significant decrease in serum testosterone and gonadotropins, females show normal values of estradiol, progesterone, LH and FSH during all estrus cycle stages. In this work, we observed that the postovariectomy rise of LH and FSH was significantly lower in the IPL nude females. We studied also the effect of acute (1 injection of 25 micrograms/rat E2Bz) or long-term (E2Bz capsule for 8 days) estradiol benzoate (E2Bz) treatment, with or without progesterone injection (5 mg/rat) in ovariectomized (OVX) IPL and normal females. The sensitivity of gonadotropins to E2 negative feedback is decreased in the IPL nude rats, result in agreement with previous reports and which could be linked to both hypoprolactinemia and decreased beta-endorphin observed in the IPL nude rat. The responsiveness of LH to LHRH was also tested in OVX and OVX + E2Bz or OVX + E2B + P treated. In OVX females responsiveness of LH to LHRH was similar in IPL nude to that of normal females. However, LH responsiveness in acute and long-term steroid-treated OVX IPL nude was significantly depressed. Since the mechanism whereby PRL interacts with steroids to modify gonadotropin secretion is still unexplained, IPL nude rat could be a good model to study it.
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PMID:Steroid regulation of gonadotropins in genetically hypoprolactinemic females (IPL nude rats). 308 74