Antéhypophyse

L'antéhypophyse (ou adénohypophyse ou hypophyse antérieure) est le lobe antérieur de l'hypophyse et fait partie de l'appareil endocrinien. Sous l'influence de l'hypothalamus, l'antéhypophyse produit et sécrète diverses hormones peptidiques qui régulent divers processus physiologiques, tels le stress, la croissance et la reproduction. Elle sécrète l'hormone de croissance (GH), la prolactine (PRL), l'hormone folliculo-stimulante (FSH) et l'hormone lutéinisante (LH), la thyréostimuline (TSH), l'hormone adrénocorticotrope (ACTH), la mélano-stimuline (MSH), des endorphines, et d'autres hormones (beta-lipotropine notamment). Hormis l'hormone de croissance et la prolactine, ce sont des stimulines, dont le rôle est d'activer les sécrétions hormonales des glandes endocrines périphériques. En cas de défaut de production on parle d'hypopituitarisme (insuffisance antéhypophysaire). Il peut s'agir d'un déficit global ou localisé (insuffisance thyréotrope par exemple). Lorsque le déficit conce

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (6)

Publications associées

Chargement

Personnes associées (1)

Personnes associées

Chargement

Unités associées (1)

Unités associées

Chargement

Concepts associés (62)

Concepts associés

Chargement

Cours associés (6)

Cours associés

Chargement

Séances de cours associées (13)

Afficher plus

Séances de cours associées

Chargement

Metabolic activation pattern of distinct hippocampal subregions during spatial learning and memory retrieval

Pierre Magistretti, Luc Pellerin

Activation dynamics of hippocampal subregions during spatial learning and their interplay with neocortical regions is an important dimension in the understanding of hippocampal function. Using the (14C)-2-deoxyglucose autoradiographic method, we have characterized the metabolic changes occurring in hippocampal subregions in mice while learning an eight-arm radial maze task. Autoradiogram densitometry revealed a heterogeneous and evolving pattern of enhanced metabolic activity throughout the hippocampus during the training period and on recall. In the early stages of training, activity was enhanced in the CA1 area from the intermediate portion to the posterior end as well as in the CA3 area within the intermediate portion of the hippocampus. At later stages, CA1 and CA3 activations spread over the entire longitudinal axis, while dentate gyrus (DG) activation occurred from the anterior to the intermediate zone. Activation of the retrosplenial cortex but not the amygdala was also observed during the learning process. On recall, only DG activation was observed in the same anterior part of the hippocampus. These results suggest the existence of a functional segmentation of the hippocampus, each subregion being dynamically but also differentially recruited along the acquisition, consolidation, and retrieval process in parallel with some neocortical sites.

2005

Chargement

Actions of VIP, hGRF, PHI and secretin: comparative studies in cerebral cortex and adenohypophysis

Pierre Magistretti, Jean-Luc Martin

We have examined the effects of hGRF on cyclic AMP and glycogen levels in mouse cerebral cortical slices. hGRF-44-NH2 and hGRF-28-OH did not stimulate cyclic AMP formation nor glycogenolysis and did not antagonize the stimulatory effects of VIP on cyclic AMP formation and glycogenolysis. These observations indicate that despite the structural homologies with VIP, hGRF does not interact with VIP receptors coupled to adenylate cyclase in mouse cerebral cortex. This is in contrast with observations in other tissues and species, such as rat and human intestinal epithelial membranes and rat pancreas. We have also compared the effects of hGRF, VIP, PHI and secretin on Growth Hormone (GH) release and cyclic AMP levels in anterior pituitary cells in vitro. VIP and PHI, but not secretin, promote at a high concentration (10(-6) M) a small but significant release of GH. This GH release is accompanied by increases in cyclic AMP levels. The concentration of VIP and PHI required to elicit these effects is high and suggests that VIP and PHI act as low affinity pharmacological analogs of hGRF on hGRF pituitary receptors.

1986

Chargement

Signals from lateral plate mesoderm instruct endoderm toward a pancreatic fate

Anne Grapin-Botton, Mithlesh Kumar

During embryonic development, organs arise along the gut tube as a series of buds in a stereotyped anterior-posterior (A-P) pattern. Using chick-quail chimeras and in vitro tissue recombination, we studied the interactions governing the. induction and maintenance of endodermal organ identify focusing on the pancreas. Though several permissive signals in pancreatic development have been previously identified, here we provide evidence that lateral plate mesoderm sends instructive signals to the endoderm, signals that induce expression of the pancreatic genes Pdx1, p48, Nkx6.1, glucagon, and insulin. Moreover, this instructive signal directs cells to form ectopic insulin-positive islet-like clusters in endoderm that would otherwise form more rostral organs. Once generated, endocrine cells no longer require interaction with mesoderm, but nonendocrine cells continue to require permissive signals from the mesoderm. Stimulation of activin, BMP, or retinoic acid signaling is sufficient to induce Pdx1 expression in endoderm anterior to the pancreas. Lateral plate mesoderm appears to pattern the endoderm in a posterior-dominant fashion as first noted in the patterning of the neural tube at the same embryonic stage. These findings argue for a central role of the mesoderm in coordinating the A-P pattern of all three primary germ layers. (C) 2003 Elsevier Science (USA). All rights reserved.

2003

Chargement

BIO-450: Molecular endocrinology

We will define the concept of homeostasis and principles of hormone action and the molecular mechanisms underlying them. Interactions with the environment and pertinent public health issues will be analyzed and preventative strategies will be discussed.

BIO-480: Neuroscience: from molecular mechanisms to disease

The goal of the course is to guide students through the essential aspects of molecular neuroscience and neurodegenerative diseases. The student will gain the ability to dissect the molecular basis of disease in the nervous system in order to begin to understand and identify therapeutic strategies.

BIO-464: Scientific project design in cell and developmental biology

Students are lead to understand selected concepts in cell and developmental biology, primarily through the analysis of scientific literature, and then to apply these concepts to the design and execution of a group project in the Gönczy or Oates laboratory.

Hypothalamus

thumb|250px|Vue tridimensionnelle de l'hypothalamus (en rouge). L'hypothalamus (du grec : ὑπό, hypo = dessous et θάλαμος, thálamos = chambre, cavité) est une structure du système nerveux central, sit

Hypophyse

Lhypophyse (du grec ancien : ὑποφύσις, hupophusis = excroissance par-dessous) ou glande pituitaire est une glande endocrine qui secrète de nombreuses hormones. L'hypophyse se trouve dans une cavit

Système endocrinien

vignette|Principales glandes du système hormonal ; 1 et 2 Épiphyse, hypophyse et hypothalamus 3 - Thyroïde 4 - Thymus 5 - Surrénales 6 - Pancréas endocrine 7 - Ova