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This Article Accepted manuscript (PDF) All Versions of this Article: JOE-08-0084v1 198/1/185    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Vinson, G Articles by Barker, S. Search for Related Content PubMed PubMed Citation Articles by Vinson, G Articles by Barker, S.

G Vinson, School of Biological & Chemical Sciences, Queen Mary, University of London, London, E1 4NS, United Kingdom
C Brennan, School of Biological & Chemical Sciences, Queen Mary, University of London, London, United Kingdom
A Chittka, School of Biological & Chemical Sciences, Queen Mary, University of London, London, United Kingdom
S Barker, School of Biological and Chemical Studies, Queen Mary, University of London, London, United Kingdom

Correspondence: G Vinson, Email: g.p.vinson{at}qmul.ac.uk

Abstract

Although the zonation of the adrenal cortex has a clear functional role, the mechanisms that maintain it remain largely conjectural. The concept that an outer proliferative layer gives rise to cells that migrate inwards, adopting sequentially the zona glomerulosa, fasciculata and reticularis phenotypes, has yet to be explained mechanistically.

In other tissues, Eph receptor/ephrin signalling provides a mechanism for cellular orientation and migration patterns.

Real time -PCR and other methods were used to determine the possible role of Eph/ephrin systems in the rat adrenal.

Messenger RNA coding for several members of the Eph receptor family was detected, but of these, EphA2 provided the closest parallel to zonal organisation. In situ hybridisation showed that EphA2 mRNA and EphA protein were predominantly located in the zona glomerulosa. Its transcription closely reflected expected changes in the glomerulosa phenotype, thus it was increased after a low sodium diet, but decreased by pretreatment with the angiotensin converting enzyme inhibitor, captopril. It was also decreased by ACTH treatment, but unaffected by betamethasone. Messenger RNA coding for ephrin A1, the major ligand for the Eph A receptors, was also detected in the rat adrenal, though changes evoked by the various pretreatments did not clearly reflect the expected changes in zonal function.

Because the maintenance of cellular zonation requires clear positional signals within the adrenal cortex, these data support a role for Eph forward and reverse signalling in the maintenance of adrenocortical zonation.