Canna~Fangled Abstracts

Hypothalamus-pituitary axis: an obligatory target for endocannabinoids to inhibit steroidogenesis in frog testis.

By February 21, 2014No Comments
2014 Feb 21. pii: S0016-6480(14)00053-7. doi: 10.1016/j.ygcen.2014.02.010. [Epub ahead of print]

pm8Hypothalamus-pituitary axis: an obligatory target for endocannabinoids to inhibit steroidogenesis in frog testis.

Abstract

Endocannabinoids – primarily anandamide (AEA) and 2-arachidonoylglycerol (2-AG) – are lipophilic molecules that bind tocannabinoid receptors (CB1 and CB2). They affect neuroendocrine activity inhibiting gonadotropin releasing hormone (GnRH) secretion and testosterone production in rodents, through a molecular mechanism supposed to be hypothalamus dependent. In order to investigate such a role, we choose the seasonal breeder, the anuran amphibian Rana esculenta, an experimental model in which components of the endocannabinoid system have been characterized. In February, at the onset of a new spermatogenetic wave, we carried out in vitro incubations of frog testis with AEA, at 10-9 M dose. Such a treatment had no effect on the expression of cytochrome P450 17alpha hydroxylase/17,20 lyase (cyp17) nor 3-β-hydroxysteroid dehydrogenase/Δ-5-4 isomerase (3β-HSD), key enzymes of steroidogenesis. To understand whether or not the functionality of the hypothalamus-pituitary axis could be essential to support the role of endocannabinoids in steroidogenesis, frogs were injected with AEA, at 10-8M dose. Differently from in vitro experiment, the in vivo administration of AEA reduced the expression of cyp17 and 3β-HSD. Whereas the effect on 3β-HSD was counteracted by SR141716A (Rimonabant) – a selective antagonist of CB1, thus indicating a CB1 dependent modulation – the effect on cyp17 was not, suggesting a possible involvement of receptors other than CB1, probably the type-1 vanilloid receptor (TRPV1), since AEA works as an endocannabinoid and an endovanilloid as well. In conclusion our results indicate that endocannabinoids, via CB1, inhibit the expression of 3β-HSD in frog testis travelling along the hypothalamus-pituitary axis.
Copyright © 2014. Published by Elsevier Inc.

KEYWORDS:

Amphibian, Endocannabinoid system, Spermatogenesis, Steroidogenesis

PMID:

 24566122
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