Disease relevance of Pituitary Gland, Posterior

• The results suggest that activation of the baroreceptor reflex induces the release of endothelin into plasma, probably from the neurohypophysis, and they raise the possibility that impaired endothelin release contributes to the orthostatic hypotension of patients with primary autonomic failure [1].
• The same dehydration stimulus resulted in an increase in IL-6 immunoreactivity in the axons of the internal zone of the median eminence and a marked reduction in IL-6-like material in the posterior pituitary gland [2].
• In normal humans, arginine vasopressin and oxytocin are released acutely from the posterior pituitary gland in response to hypoglycemia, and their release may assist counterregulation [3].
• The content of corticotropin releasing factor did not differ in the neurohypophysis in 3-week-old rats but began to decrease at 6 weeks of age (p less than 0.01) and continued to decrease during the development of hypertension (p less than 0.01) [4].
• Central diabetes insipidus, characterized by severe polyuria and polydipsia, is a disorder resulting from deficient secretion of the small neuropeptide hormone vasopressin in the neurohypophysis [5].

Psychiatry related information on Pituitary Gland, Posterior

• To analyze rapid changes in energy metabolism in the neurohypophysis, pO2 was measured in the tissue in vitro with a miniature O2 electrode (tip diameter less than 100 microns, 90% response time less than 3 s) [6].
• The content of AVP and OT in the neurohypophysis was unaffected by food deprivation and subsequent refeeding.(ABSTRACT TRUNCATED AT 250 WORDS)[7]
• PURPOSE: To evaluate the effect of water deprivation on the signal intensity of the posterior pituitary gland on T1-weighted MR images and correlate the signal intensity with the plasma vasopressin concentration [8].

High impact information on Pituitary Gland, Posterior

• The hormones vasopressin and oxytocin released from the HNS at the neurohypophysis serve homeostatic functions of water balance and reproduction [9].
• Relaxin affects the release of oxytocin and vasopressin from the neurohypophysis [10].
• Extracts of neurohypophysis have been shown to contain substantial amounts of Met- and Leu-enkephalin, and Leu-enkephalin-immunoreactive (IR) nerve fibres originating in the magnocellular hypothalamic nuclei have been described in the neural lobe, where the two hormones are secreted [11].
• Calcium-dependent somatostatin secretion from rat neurohypophysis in vitro [12].
• Methionine and leucine enkephalin in rat neurohypophysis: different responses to osmotic stimuli and T2 toxin [13].

Chemical compound and disease context of Pituitary Gland, Posterior

• The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) results either from ectopic production or inappropriate release of antidiuretic hormone from the neurohypophysis [14].
• The content of vasopressin, oxytocin, neurophysin, leucine-enkephalin, methionine-enkephalin, dynorphin-(1-13), and alpha-neoendorphin in the rat neurohypophysis was measured after different periods of dehydration and after depolarisation of isolated neural lobes and of neurosecretory nerve endings [15].
• Under extreme dehydration (8 and 12 days) the vasopressin depletion in the neurohypophysis was significantly inhibited in the carbachol-treated animals [16].

Biological context of Pituitary Gland, Posterior

• Oxytocin secretion from the posterior pituitary gland is increased during parturition, stimulated by the uterine contractions that forcefully expel the fetuses [17].
• Depolarizing afterpotentials (DAPs) that follow action potentials in magnocellular neurosecretory cells (MNCs) are thought to underlie the generation of phasic firing, a pattern that optimizes vasopressin release from the neurohypophysis [18].
• 6. We conclude that the rise in [K+]o that accompanies high-frequency activation of axons and terminals in the neurohypophysis contributes to the facilitation of hormone release with increasing frequencies of stimulation, and in particular to the efficiency of the milk-ejection burst discharge of oxytocin neurones for evoking oxytocin release [19].
• Oxytocin-containing axons project from the hypothalamic paraventricular nucleus to the neurohypophysis and thoracic spinal cord to ultimately influence uterine contractions and autonomic activity, respectively [20].
• Many ER profiles in non-incubated sections and in G6Pase cytochemical preparations of salt-stressed neurohypophyses were wrapped around or interspersed among secretory granules, multilamellar bodies, and vacuoles that may represent forms of lysosomes involved in autophagy and crinophagy [21].

Anatomical context of Pituitary Gland, Posterior

• Differences in mRNA abundance were noted in oxytocin neurons throughout the hypothalamus, including those known to project as magnocellular neurons to the neurohypophysis and those of parvocellular origin thought to make wholly intracerebral connections [22].
• Previous studies indicated that the central nervous system induces release of the cardiac hormone atrial natriuretic peptide (ANP) by release of oxytocin from the neurohypophysis [23].
• Neurons expressing hITF were identified in two magnocellular hypothalamic nuclei, the paraventricular and periventricular nuclei. hITF polypeptide was also observed in Herring bodies of the neurohypophysis and in secretory cells of the adenohypophysis [24].
• Vasopressin is synthesized by magnocellular neurons in supraoptic (SON) and paraventricular (PVN) hypothalamic nuclei and released by their axon terminals in the neurohypophysis (NH) [25].
• The neurohypophysis, endothelium, and connective tissue expressed no ER gene [26].

Associations of Pituitary Gland, Posterior with chemical compounds

• High angiotensin-converting enzyme activity in the neurohypophysis of Brattleboro rats [27].
• In this article, single-channel recordings are used to demonstrate that ethanol, at concentrations constituting legal intoxication, inhibits dihydropyridine-sensitive "L-type" Ca2+ channels in isolated nerve terminals of the rat neurohypophysis [28].
• Immunocytochemistry and immunoblot analysis showed that during basal conditions of HNS secretion, there are higher levels of this glycosylphosphatidyl inositol-anchored protein in the neurohypophysis, where their axons terminate, than in the hypothalamic nuclei containing their somata [29].
• Vasotocin (VT, the antidiuretic hormone of birds) is synthesized by diencephalic magnocellular neurons projecting to the neurohypophysis [30].
• To compare the estrogen-responsive Np in plasma with human OT-Np which is present in the posterior pituitary gland, the Np fraction of post-DES plasma was concentrated by double precipitation with ammonium sulfate and applied to ampholyte displacement and Sephadex G-75 columns [31].

Gene context of Pituitary Gland, Posterior

• Histological analysis of the operative specimen demonstrated a granular cell tumor of the neurohypophysis, which when stained proved negative for pituitary hormones and GHRH [32].
• In 81% of the IGHD patients and in 91% of the MPHD patients the location of the neurohypophysis was ectopic [33].
• On the contrary, i.c.v. injection of Gal to salt-loaded rats caused a marked raise in AVP and OT level in the hypothalamus and neurohypophysis with subsequent diminution of both neurohormones concentration in blood plasma [34].
• AVP is usually detectable in the human fetal neurohypophysis at 11 to 12 weeks gestation and increases over 1000-fold over the next 12 to 16 weeks [35].
• Only in the neurohypophysis, SS-14 increased the concentration of HA 10 min after injection, but this response was not dose-related [36].

Analytical, diagnostic and therapeutic context of Pituitary Gland, Posterior

• 4. Vasopressin release from the neurohypophysis, measured by specific radioimmunoassay, was facilitated by stimulation in parallel with a parameter of [Ca2+]o decrease multiplied by Ca2+ influx [37].
• 5. Potassium-sensitive microelectrodes were placed in the neurohypophysis of rats anaesthetized with urethane [38].
• Release of AVP from isolated intact neurohypophyses, induced by either electrical stimulation or elevated potassium, was inhibited by clinically relevant concentrations of EtOH. "Whole-cell" patch-clamp recording methods were used to study the effects of EtOH on voltage-activated Ca++ currents (ICa) in the peptidergic nerve terminals [39].
• A first phase occurred within 15 min which may be due to an immediate release of stored cytokine-induced neutrophil chemoattractant in the neurohypophysis, since hypophysectomy completely blocked this phase [40].
• BC1 RNA and vasopressin mRNA in rat neurohypophysis: axonal compartmentalization and differential regulation during dehydration and rehydration [41].

References