Elsevier

Steroids

Volume 59, Issue 11, November 1994, Pages 661-667
Steroids

The receptor-mediated action of sex steroid binding protein (SBP, SHBG): Accumulation of cAMP in MCF-7 cells under SBP and estradiol treatment

https://doi.org/10.1016/0039-128X(94)90023-XGet rights and content

Abstract

The interaction of sex steroid binding protein (SBP) with its specific receptor in MCF-7 cell (estrogen-sensitive human breast cancer cells), followed by the binding of estradiol (E2) to the complex SBP-receptor, induced a significant accumulation of intracellular cAMP. SBP alone as well as E2 alone did not elicit any modification of the nucleotide. The maximal increase in cAMP was observed with 1 nM SBP + 1 nM E2. Increasin doses of both SBP and E2, even raising cAMP levels with respect to basal, did not give any higher response. Both testosterone and dihydrotestosterone, used instead of E2, were not able to induce any significant modification of cAMP. E2-induced MCF-7 cell proliferation was significantly reduced by 8Br-cAMP, MDA-MB 231 cells (estrogen-insensitive breast cancer cells) were not shown to bind SBP, or to respond to SBP + E2 as far as both their proliferation and cAMP content are concerned. In summary, the present study provides evidence that the SBP receptor is part of the G-protein receptor family, and that SBP can act as modulator of E2 action at cell site through the second messenger cAMP. (Steroids 59:661–667, 1994)

References (23)

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