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Pituitary Gland
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Both hormones are synthesized in the cell bodies of the SON and PVN of the hypothalamus. Each hormone binds to a specific transport protein, neurophysin, and the hormone–neurophysin complex is transported in tiny vesicles along axons. These vesicles coalesce to form storage granules in the nerve terminals in the posterior pituitary, and the granules are released by exocytosis. The neuropeptides enter the systemic circulation via the venous drainage of the posterior pituitary into the cavernous sinus and the internal jugular vein. In the systemic circulation, they are unbound and rapidly cleared by the kidney and to a lesser extent, by the liver. Their half-life is between 1 and 5 minutes.
Regulation of the Pituitary Gland by Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
Neurophysin I is associated with AVP, while neurophysin II is associated with OT. Both are carrier proteins that after cleavage are non-covalently linked to their respective peptides within the secretory granules. The self-association of the peptide-neurophysin complex plays critical roles in the sorting of the precursor protein to the regulated secretory pathway. The neurophysins are also responsible for the protection of the peptides, which are present at high concentrations within the secretory granules, against disulfide exchange and degradation. During exocytosis, the neurophysins are released together with their respective peptides from the nerve terminals into the circulation and are detectable in the cerebrospinal fluid. Although there is significant information on the structure and function of the neurophysins as carrier proteins, it is presently unknown whether circulating neurophysins have independent functions as hormones or if they have specific targets in the periphery.
Summation of Basic Endocrine Data
Published in George H. Gass, Harold M. Kaplan, Handbook of Endocrinology, 2020
Several factors influence release from the posterior pituitary to the plasma. The hormones dissociate from neurophysin after their secretion. The hypothalamus responds first to any one or more of a great diversity of stimuli and in turn controls the hormonal release. As one example, the release is influenced by extracellular fluid osmolarity. Ingestion of water inhibits release.
Non-invasive diagnosis of endometriosis and moderate-severe endometriosis with serum CA125, endocan, YKL-40, and copeptin quadruple panel
Published in Journal of Obstetrics and Gynaecology, 2021
Onur Guralp, Baris Kaya, Nevin Tüten, Mine Kucur, Eduard Malik, Abdullah Tüten
The following kits were used for the measurement of endocan, CA125, YKL-40 and copeptin by strictly following the instructions of the manufacturer:Serum endocan: ELISA, Aviscera Bioscience Inc, Catalog No: SK00318-01 Santa Clara, CA, USA. The absorbances were measured at 450 nm. The assay-range, sensitivity, intra- and inter-assay variations of the endocan kit were 0.40–20 ng/mL, 1.56 ng/mL, 6–8 and 10–12%, respectively.CA125: IMMULITE 2000, DPC, Los Angeles, CA, USA. The intra- and inter-assay coefficient of variations were <10% and <15%, respectively.YKL-40: ELISA, Quidel, Santa Clara, CA. The assay-range, sensitivity, intra- and inter-assay variations were 15.6–300 ng/mL, 20 ng/mL, 3.6% and 5.3%, respectively.Copeptin: Human Vasopressin-Neurophysin 2-copeptin ELISA kit: EIAab Wuhan EIAab Science Co. Ltd., Wuhan, China. The assay-range, sensitivity, intra- and inter-assay variations were 15.6–1000 pg/mL, 10 pg/mL, 5–5.5% and 6–7.8% respectively.
Role of copeptin in diagnosis and outcome prediction in patients with heart failure: a systematic review and meta-analysis
Published in Biomarkers, 2022
Jakub Michal Zimodro, Aleksandra Gasecka, Milosz Jaguszewski, Sandra Amanowicz, Marta Szkiela, Andrea Denegri, Michal Pruc, Piotr Duchnowski, Frank W. Peacock, Zubaid Rafique, Lukasz Szarpak
Increased activity of the vasopressin system has an important impact on the pathophysiology of HF (Francis et al. 1984). AVP, a nonapeptide, is synthetized in the supraoptic and paraventricular nuclei of the hypothalamus as pre-pro-AVP, which is then cleaved into pro-AVP. Subsequently, pro-AVP is cleaved into AVP, inactive copeptin and neurophysin-II, all of which are released in equimolar amounts (Demiselle et al. 2020). Neurophysin-II participates in transport of AVP to the neurohypophysis, where AVP is stored. The physiological role of copeptin, a 39-aminoacid glycoprotein, remains uncertain, but is hypothesized to assist in pro-AVP formation (Balling and Gustafsson 2014).