Two peptides that have been previously colocalized in the gonadotrops (LeuEnkephalin with LH and ACTH with FSH) can stimulate the release of gonadotropins in primary culture of anterior pituitary cells. In presence of both substances, and in contrast to LHRH induced secretion, the augmentation of LH release is never dose dependent. It is always significantly higher than controls, for high (10(-6) M) or low concentrations (10(-12) M). Prolactin release is only modified in presence of Leu-Enkephalin. Met-Enkephalin does not increase the liberation of LH, FSH, or Prolactin in vitro. Furthermore, while Leu-Enkephalin can enhance the stimulating effect of LHRH, ACTH has a negative interaction with LHRH, when these two peptides are added together in incubation medium. These results demonstrate that Leu-Enkephalin and ACTH can in vitro modulate the release of gonadotrophins at the pituitary level suggesting a physiological role for such colocalization.
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http://dx.doi.org/10.1016/0143-4179(90)90125-i | DOI Listing |
Front Physiol
June 2023
Colin G. Scanes, Department of Biological Science, University of Wisconsin Milwaukee, Milwaukee, WI, United States.
The present review considers the putative hormonal opioid peptides in birds. In birds and all other vertebrates, there are four opioid related genes encoding a series of peptides. These genes are, respectively, proenkephalin (PENK), prodynorphin (PDYN), pronociceptin (PNOC) and proopiomelanocortin (POMC).
View Article and Find Full Text PDFEndokrynol Pol
June 2010
Department of Pathophysiology and Endocrinology, Medical University of Silesia, Zabrze, Katowice, Poland.
Introduction: A multitude of mechanisms have been implicated in the pathophysiology of epilepsy.
Objective: To assess mean daily plasma concentrations of ACTH, cortisol, DHEAS, leu-enkephalin, and beta-endorphin in epileptic patients with complex partial seizures evolving to tonic-clonic in relation to frequency of seizure occurrence (groups with seizure occurrences - several per week and several per year) and duration of the disease (groups less than and more than 10 years). We decided to analyse mean daily values of beta-endorphin and leu-enkephalin because of significant differences in concentrations of these substances in blood during the day.
Cell Biochem Funct
April 2008
Department of Biochemistry, Kurukshetra University, Kurukshetra, Haryana, India.
DPP-III from goat brain was purified to apparent electrophoretic homogeneity which showed several characteristics similar to other reported DPP-IIIs although it possesses dissimilar molecular weight and different inhibition behavior. Thin layer chromatographic studies with goat brain DPP-III revealed that it hydrolyses Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu) at the Gly-Gly bond producing Tyr-Gly and Gly-Phe-Leu with no further degradation of liberated tripeptide. (Ala)(4) is hydrolyzed to dialanine whereas trialanine is not cleaved.
View Article and Find Full Text PDFEndocr Res
November 2000
Pediatric and Reproductive Endocrinology Branch, NICHD, NIH, Bethesda, MD 20892, USA.
Adrenocortical steroidogenesis is regulated in addition to a central regulation via the hypothalamus-pituitary-adrenal axis by intra-adrenal mechanisms involving the adrenal medulla. We could previously show that adrenocortical steroidogenesis is stimulated by co-culturing bovine adrenocortical cells with medullary chromaffin cells. This stimulation was due to soluble factors released from the chromaffin cells under basal, unstimulated conditions and involved the increased expression of P450 enzymes, StAR and de novo protein synthesis.
View Article and Find Full Text PDFNutr Neurosci
July 2016
c Western Human Nutrition Research Center, Agricultural Research Service , San Francisco , CA 94129 , USA.
Copper plays an important role in cardiac and brain function possibly through endocrine and neuroendocrine systems. The syndrome of copper deficiency is worsened by dietary fructose and other trace metals such as zinc. We investigated the effect of a low copper diet on plasma opioid peptides in 11 healthy young volunteers who were fed foods low in copper but adequate in all other nutrients.
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