Magnocellular Neurons and Posterior Pituitary Function

2016 ◽  
pp. 1701-1741 ◽  
Author(s):  
Colin H. Brown
Keyword(s):  
Pituitary Function ◽  
Posterior Pituitary ◽  
Magnocellular Neurons

scholarly journals Secretin as a neurohypophysial factor regulating body water homeostasis

2009 ◽  
Vol 106 (37) ◽  
pp. 15961-15966 ◽  
Author(s):  
Jessica Y. S. Chu ◽  
Leo T. O. Lee ◽  
C. H. Lai ◽  
H. Vaudry ◽  
Y. S. Chan ◽  
...  
Keyword(s):  
Direct Effect ◽  
Body Water ◽  
Posterior Pituitary ◽  
Water Reabsorption ◽  
Magnocellular Neurons ◽  
Water Homeostasis ◽  
Neurohypophysial Hormones ◽  
New Concepts ◽  
Multiple Levels

Hypothalamic magnocellular neurons express either one of the neurohypophysial hormones, vasopressin or oxytocin, along with different neuropeptides or neuromodulators. Axonal terminals of these neurons are generally accepted to release solely the two hormones but not others into the circulation. Here, we show that secretin, originally isolated from upper intestinal mucosal extract, is present throughout the hypothalamo–neurohypophysial axis and that it is released from the posterior pituitary under plasma hyperosmolality conditions. In the hypothalamus, it stimulates vasopressin expression and release. Considering these findings together with our previous findings that show a direct effect of secretin on renal water reabsorption, we propose here that secretin works at multiple levels in the hypothalamus, pituitary, and kidney to regulate water homeostasis. Findings presented here challenge previous understanding regarding the neurohypophysis and could provide new concepts in treating disorders related to osmoregulation.

ANTERIOR AND POSTERIOR PITUITARY FUNCTION IN BRAIN-STEM-DEAD DONORS

1989 ◽  
Vol 47 (5) ◽  
pp. 828-833 ◽  
Author(s):  
TREVOR A. HOWLETT ◽  
ANNE M. KEOGH ◽  
LES PERRY ◽  
RICHARD TOUZEL ◽  
LESLEY H. REES
Keyword(s):  
Brain Stem ◽  
Pituitary Function ◽  
Posterior Pituitary

Pituitary assessment strategy

2011 ◽  
pp. 127-136
Author(s):  
W. M. Drake ◽  
P. J. Trainer
Keyword(s):  
Diabetes Insipidus ◽  
Anterior Pituitary ◽  
Patient Management ◽  
Pituitary Function ◽  
Rational Approach ◽  
Posterior Pituitary ◽  
Physiological Basis ◽  
Assessment Strategy ◽  
Anterior Pituitary Function ◽  
Treatment Of Diabetes

The optimum methods of testing anterior and posterior pituitary function and the interpretation of the results are subjects of continuing debate. The syndromes associated with and consequences of hypo- and hyperpituitarism, and the diagnosis and treatment of diabetes insipidus are all discussed elsewhere in this book. The intention of this chapter is to describe the physiological basis and evidence in favour of the various available tests of anterior pituitary function, discuss the limitations of using artificial assessments on which to base patient management decisions and, ultimately, endeavour to produce a rational approach to the investigation of suspected hypopituitarism.

scholarly journals Anterior and Posterior Pituitary Function Testing with Simultaneous Insulin Tolerance Test and a Novel Copeptin Assay

2007 ◽  
Vol 92 (7) ◽  
pp. 2640-2643 ◽  
Author(s):  
Mira Katan ◽  
Nils G. Morgenthaler ◽  
Kashinath C. S. Dixit ◽  
Jonas Rutishauser ◽  
Georg E. Brabant ◽  
...  
Keyword(s):  
Diabetes Insipidus ◽  
Anterior Pituitary ◽  
Insulin Injection ◽  
Tolerance Test ◽  
Pituitary Function ◽  
Posterior Pituitary ◽  
Maximum Increase ◽  
Maximal Increase ◽  
Patients With Diabetes ◽  
Pituitary Function Test

Abstract Context: Posterior pituitary function in patients with suspected diabetes insipidus is usually assessed by a water deprivation test. Alternatively, a nonosmotic stimulus such as hypoglycemia may be used to stimulate vasopressin [arginine vasopressin (AVP)] secretion. Plasma AVP measurement may aid in the diagnosis and, especially, differential diagnosis of diabetes insipidus and polydipsia. However, AVP measurement is cumbersome. Copeptin, the stable C-terminal glycopeptide of the AVP prohormone, is stoichiometrically secreted from the posterior pituitary. Objective: The aim was to study the value of copeptin levels in the diagnosis of diabetes insipidus during insulin-induced hypoglycemia. Patients and Methods: A total of 38 patients were studied during insulin-induced hypoglycemia as part of a combined pituitary function test for possible anterior pituitary disease. There were 29 patients who had normal posterior pituitary function, and nine had central diabetes insipidus. Blood sampling was done before and 30, 45, and 90 min after iv insulin injection. Copeptin was measured with a new sandwich immunoassay. Results: Patients with intact posterior pituitary function had basal copeptin levels of 3.7 ± 1.5 pm, with a maximal increase to 11.1 ± 4.6 pm 45 min after insulin injection. Copeptin levels in patients with diabetes insipidus were 2.4 ± 0.5 pm before insulin injection, with a maximum increase to 3.7 ± 0.7 pm. Both basal and stimulated copeptin levels were lower in patients with diabetes insipidus as compared with patients with intact posterior pituitary function. A stimulated copeptin level 45 min after insulin injection of less than 4.75 pm had an optimal diagnostic accuracy to detect diabetes insipidus. Conclusion: Copeptin measurement may be used to assess posterior together with anterior pituitary function during insulin-induced hypoglycemia.

scholarly journals A Longitudinal Study of Vasopressin Cell Antibodies, Posterior Pituitary Function, and Magnetic Resonance Imaging Evaluations in Subclinical Autoimmune Central Diabetes Insipidus

1999 ◽  
Vol 84 (9) ◽  
pp. 3047-3051 ◽  
Author(s):  
A. De Bellis ◽  
A. Colao ◽  
F. Di Salle ◽  
V. I. Muccitelli ◽  
S. Iorio ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Autoimmune Diseases ◽  
Diabetes Insipidus ◽  
Central Diabetes Insipidus ◽  
Pituitary Function ◽  
Study Entry ◽  
Posterior Pituitary ◽  
Resonance Imaging

Cytoplasmic autoantibodies to vasopressin-cells (AVPcAb) have been detected not only in patients with overt central diabetes insipidus (CDI), but also in patients with endocrine autoimmune diseases without CDI. This suggests that complete CDI can be preceded by a preclinical stage. Among 878 patients with endocrine autoimmune diseases without CDI, 9 patients found to be AVPcAb positive and 139 AVPcAb-negative controls were enrolled in this open prospective study. They were evaluated for AVPcAb and posterior pituitary function at least yearly for about 4 yr (range, 37–48 months); during this span, magnetic resonance imaging (MRI) of posterior pituitary and stalk was performed only in the AVPcAb-positive patients. Five of the 9 AVPcAb-positive patients had normal posterior pituitary function at study entry. They were AVPcAb positive throughout the follow-up period. At later stages of the study, 3 of them developed partial CDI, and 1 developed complete CDI. The remaining 4 patients showed impaired response to the water deprivation test at study entry and were diagnosed as having partial CDI. Two of them agreed to receive desmopressin replacement for 1 yr. After this treatment, the patients became negative for AVPcAb and displayed normal posterior pituitary function until the end of the follow-up. Conversely, the 2 untreated patients with partial CDI remained AVPcAb positive. One of them developed overt CDI. None of the controls became AVPcAb positive or developed CDI. The normal hyperintense MRI signal of the posterior pituitary, present at study entry, persisted subsequently in all 9 AVPcAb-positive patients, including those developing overt CDI, only disappearing in the late phase of complete CDI. In asymptomatic subjects, the monitoring of AVPcAb, but not MRI, seems to be useful to predict a progression toward partial/overt CDI. Early desmopressin therapy in patients with partial CDI could interrupt or delay the autoimmune damage and the progression toward clinically overt CDI.

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