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Horm Metab Res 2007; 39(4): 256-261
DOI: 10.1055/s-2007-973074
Original Clinical

© Georg Thieme Verlag KG Stuttgart · New York

Effects of Dietary Equol on the Pituitary of the Ovariectomized Rats

D. Rachoń 1 , 2 , T. Vortherms 1 , D. Seidlová-Wuttke 1 , W. Wuttke 1
  • 1Department of Clinical and Experimental Endocrinology, University of Göttingen, Robert-Koch-Strasse 40, Göttingen, Germany
  • 2Department of Immunology, Medical University of Gdańsk, ul. Dębinki 1, Gdańsk, Poland
Further Information

Publication History

received 20. 7. 2006

accepted 11. 12. 2006

Publication Date:
19 April 2007 (online)

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Abstract

The aim of our study was to evaluate the effects of dietary equol, metabolite of a phytoestrogen daidzein, on the secretion of prolactin (PRL) and lutenizing hormone (LH), as well as the expression of estrogen receptors (ERα, ERβ and truncated estrogen receptor-1 (TERP-1) in the pituitary gland of ovariectomized (ovx) female Sprague-Dawley rats. Two doses of equol (50 mg/kg of chow and 400 mg/kg of chow) were used and the results were compared with the effects of estradiol 3-benzoate (E2B), also given at two doses (4.3 mg/kg of chow and 17.3 mg/kg of chow). Treatment period was 3 months. Dietary equol administration at the high dose increased significantly serum PRL levels. This effect was also observed in the E2B group but this difference did not reach statistical significance. Surprisingly, high dose dietary equol treatment also significantly increased serum LH levels, which was in contrast to E2B treatment where serum LH levels were significantly decreased at both doses. Serum LH levels in the equol low group were unaffected. Equol treatment had no effects on pituitary ERα or ERβ gene expression. In contrast, high dose E2B treatment increased significantly pituitary ERα mRNA levels but decreased those of ERβ. Both doses of E2B also increased significantly pituitary TERP-1 mRNA levels. This effect was also observed in the equol high group but at a much smaller magnitude. In conclusion, high dose dietary equol administration to ovx rats exerts estrogenic like effects on the lactotropes and anti-estrogenic on the gonadotropes.

Key words

phytoestrogens - equol - pituitary - prolactin - LH - estrogen receptors - TERP-1

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Correspondence

Dr. D. RachońM.D., Ph.D. 

Department of Immunology

Medical University of Gdańsk

ul. Dębinki 1

80-210 Gdańsk

Poland

Phone: +48/58/349 15 35

Fax: +48/58/349 25 03

Email: drachon@amg.gda.pl