Minéralocorticoïde

Résumé

Les minéralocorticoïdes sont une classe de stéroïdes caractérisés par leur similarité avec l'aldostérone et leur influence sur le métabolisme hydrosodique. Leurs actions passent par leur liaison à un récepteur nucléaire spécifique, le récepteur des minéralocorticoïdes. Voies de synthèses Comme pour tous les stéroïdes, donc les minéralocorticoïdes, le précurseur est le cholestérol. La biosynthèse de l'aldostérone passe par une série de modifications enzymatiques transformant le cholestérol en pregnenolone déshydrogénée en 17 en progestérone, puis hydroxylée successivement en 21 pour former la désoxycorticostérone (DOC) et en 11 pour aboutir à la corticostérone précurseur commun des hormones corticoïdes. La corticostérone est oxydée en 18 par l'aldostérone synthase pour aboutir à l'aldostérone, principale hormone minéralocorticoïde chez l'humain ; chez les rongeurs, ce rôle est assuré par la corticostérone. Ces réactions sont effectuées par des enzymes cytosoliques ou mitoch

Source officielle

https://fr.wikipedia.org/wiki/Min%C3%A9ralocortico%C3%AFde

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 (2)

Publications associées

Chargement

Personnes associées

Chargement

Unités associées

Chargement

Concepts associés (18)

Concepts associés

Chargement

Cours associés (2)

Ce cours permet aux étudiants ayant suivi Morphologie I de réviser et d'approfondir leurs connaissances par l'étude de l'anatomie radiologique et du développement. L'origine de malformations fréquentes est décrite. Divers sujets requis pour l'examen d'entrée à la Passerelle sont aussi traités.

Biochemistry is a key discipline for the Life Sciences. Biological Chemistry I and II are two tightly interconnected courses that aim to describe and understand in molecular terms the processes that make life possible.

Cours associés

Chargement

Séances de cours associées (2)

Séances de cours associées

Chargement

LC-MS/MS determination of potential endocrine disruptors of cortico signalling in rivers and wastewaters

Kristin Schirmer

A targeted analytical method was established to determine a large number of chemicals known to interfere with the gluco- and mineralocorticoid signalling pathway. The analytes comprise 30 glucocorticoids and 9 mineralocorticoids. Ten out of these corticosteroids were primary metabolites. Additionally, 14 nonsteroids were included. These analytes represent a broader range of possible adverse modes of action than previously reported. For the simultaneous determination of these structurally diverse compounds, a single-step multimode solid-phase extraction and pre-concentration was applied. Extracts were separated by a short linear HPLC gradient (20 min) on a core shell RP column (2.7 mu m particle size) and compounds identified and quantified by LC-MS/MS. The method provided excellent retention time reproducibility and detection limits in the low nanograms per litre range. Untreated hospital wastewater, wastewater treatment plant influent, treated effluent and river waters were analysed to demonstrate the applicability of the method. The results show that not all compounds were sufficiently eliminated by the wastewater treatment, resulting in the presence of several steroids (similar to 20 ng/L) and nonsteroids in the final effluent, some of them at high concentrations up to 200 ng/L. Most of the detected mono-hydroxylated steroidal transformation products were found at significantly higher concentrations than their parent compounds. We therefore recommend to include these potentially bioactive metabolites in environmental toxicity assessment.

Springer Heidelberg2014

Chargement

Individual differences in anxiety trait are related to spatial learning abilities and hippocampal expression of mineralocorticoid receptors

Maria del Carmen Sandi Perez

Although high levels of anxiety might be expected to negatively influence learning and memory, it remains to be shown whether individual differences in anxiety may influence spatial learning and memory in outbred rat populations. We have studied this possibility in male Wistar rats whose levels of anxiety were first characterized as either high (HA) or low (LA) according to their behavior in the elevated plus maze or in the open field test. Subsequently, their performance in the Morris water maze was studied, a task dependent on hippocampal activity. Interestingly, LA rats showed a faster acquisition and better memory in the water maze when compared to HA rats. Indeed, this difference in performance could mainly be attributed to the increase in thigmotactic behavior (swimming in circles close to the maze walls) displayed by HA rats during spatial navigation. Glucocorticoids are known to affect the state of anxiety and the hippocampus is the main target of glucocorticoids in the brain. Hence, we investigated whether the hippocampal expression of the two classical corticosteroid receptors, mineralocorticoid (MR) and glucocorticoid (GR) differed in the two groups of rats. We found that LA rats displayed higher hippocampal expression of MR but not GR than HA rats. Indeed, the expression levels for these receptors were positively correlated with the amount of time spent by the animals in the open arms of the elevated plus maze. Moreover, we present evidence that the levels of anxiety quantified in the first stages of our study constitute a trait rather than a state. Taken together, this study has generated evidence of a close interaction between the anxiety trait, hippocampal MR expression and the learning abilities of individuals in stressful spatial orientation tasks.

2006

Chargement