Desensitization of the adrenocorticotrophin responses to arginine vasopressin and corticotrophin-releasing hormone in ovine anterior pituitary cells

in Journal of Endocrinology
Authors:
A Hassan
Search for other papers by A Hassan in
Current site
Google Scholar
PubMed Close
,
S Chacko
Search for other papers by S Chacko in
Current site
Google Scholar
PubMed Close
, and
D Mason
Search for other papers by D Mason in
Current site
Google Scholar
PubMed Close
DOI:
https://doi.org/10.1677/joe.0.1780491
Volume/Issue:
Volume 178: Issue 3
Article Type:
Other
Page Range:
491–501
Online Publication Date:
01 Sep 2003
Free access

Sign up for journal news

Following repeated or prolonged exposure to either corticotrophin-releasing hormone (CRH) or arginine vasopressin (AVP), pituitary adrenocorticotrophin (ACTH) responsiveness is reduced. This study compared the characteristics of desensitization to CRH and AVP in perifused ovine anterior pituitary cells. Desensitization to AVP occurred at relatively low AVP concentrations and was both rapid and readily reversible. Treatment for 25 min with AVP at concentrations greater than 2 nM caused significant reductions in the response to a subsequent 5 min 100 nM AVP pulse (IC(50)=6.54 nM). Significant desensitization was observed following pretreatment with 5 nM AVP for as briefly as 5 min. Desensitization was greater following a 10 min pretreatment, but longer exposures caused no further increase. Resensitization was complete within 40 min following 15 min treatment with 10 nM AVP. Continuous perifusion with 0.01 nM CRH had no effect on AVP-induced desensitization. Treatment with 0.1 nM CRH for either 25 or 50 min caused no reduction in the response to a subsequent 5 min stimulation with 10 nM CRH. When the pretreatment concentration was increased to 1 nM significant desensitization was observed, with a greater reduction in response occurring after 50 min treatment. Recovery of responsiveness was progressive following 50 min treatment with 1 nM CRH and was complete after 100 min. Our data show that in the sheep AVP desensitization can occur at concentrations and durations of AVP exposure within the endogenous ranges. This suggests that desensitization may play a key role in regulating ACTH secretion in vivo. If, as has been suggested, CRH acts to set corticotroph gain while AVP is the main dynamic regulator, any change in responsiveness to CRH may significantly influence the overall control of ACTH secretion.

Journal of Endocrinology is committed to supporting researchers in demonstrating the impact of their articles published in the journal.

The two types of article metrics we measure are (i) more traditional full-text views and pdf downloads, and (ii) Altmetric data, which shows the wider impact of articles in a range of non-traditional sources, such as social media.

More information is on the Reasons to publish page.

Sept 2018 onwards Past Year Past 30 Days
Full Text Views 117 40 2
PDF Downloads 94 28 2

 

  • Collapse
  • Expand
Print ISSN:
0022-0795
Online ISSN:
1479-6805
Page(s):
11
Article Type:
Other
Print Publication Date:
01 Sep 2003
Online Publication Date:
01 Sep 2003