Desensitization of beta2-adrenoceptor function in non-pregnant rat myometrium is modulated by sex steroids

in Journal of Endocrinology
Authors:
T Engstrom
Search for other papers by T Engstrom in
Current site
Google Scholar
PubMed Close
,
H Vilhardt
Search for other papers by H Vilhardt in
Current site
Google Scholar
PubMed Close
,
P Bratholm
Search for other papers by P Bratholm in
Current site
Google Scholar
PubMed Close
, and
NJ Christensen
Search for other papers by NJ Christensen in
Current site
Google Scholar
PubMed Close
DOI:
https://doi.org/10.1677/joe.0.1700147
Volume/Issue:
Volume 170: Issue 1
Article Type:
Other
Page Range:
147–155
Online Publication Date:
01 Jul 2001
Free access

Sign up for journal news

The effects of in vivo treatment with estrogen and progesterone on isoproterenol-induced uterine relaxation and beta(2)-adrenoceptor (beta(2)AR) mRNA production in non-pregnant rat myometrium were investigated. Whether homologous myometrial desensitization of beta(2)AR function was dependent on or modulated by the two steroids was also examined. Estrogen treatment alone or in combination with progesterone reduced maximal relaxation (E(max)) of isolated uterine strips subsequently challenged with isoproterenol whereas progesterone alone had no effect on this parameter. The reduction was accompanied by an enhanced beta(2)AR mRNA concentration. The concentration of isoproterenol giving half-maximal relaxing response (EC(50)) increased following estrogen treatment and this effect was curbed by progesterone. Isoproterenol had no effect on beta(2)AR transcription irrespective of the steroid regimes employed. E(max) of isolated uterine strips was reduced following prolonged in vivo treatment with isoproterenol but the effect was found only when estrogen alone was administered concomitantly. Finally, in vivo treatment with isoproterenol increased EC(50) of uterine strips subsequently stimulated with isoproterenol in vitro. This effect was independent of steroid treatment. We conclude that homologous desensitization of beta(2)AR function in non-pregnant rat myometrium in terms of sensitivity (EC(50)) is independent of sex steroids but in terms of maximal response (E(max)) occurs only in the presence of estrogen. We speculate whether progesterone withdrawal in connection with the well-known estrogen dominance at rat parturition may strengthen the desensitization induced by beta(2)AR activation and thus contribute to the transformation of the uterus from a quiescent to a highly contractile organ.

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 125 38 1
PDF Downloads 74 20 2

 

  • Collapse
  • Expand
Print ISSN:
0022-0795
Online ISSN:
1479-6805
Page(s):
9
Article Type:
Other
Print Publication Date:
01 Jul 2001
Online Publication Date:
01 Jul 2001