This Article Full Text (PDF) 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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Keightley, D. D. Articles by Okey, A. B. Search for Related Content PubMed PubMed Citation Articles by Keightley, D. D. Articles by Okey, A. B.

Effect of a Carcinogenic Oral Dose of 7,12-Dimethylbenz(a)anthracene on Receptor Binding of Estradiol-17ß in Uterus and Mammary Tissue throughout Lactation in the Rat¹

Department of Biology, University of Windsor, Windsor, Ontario, Canada N9B 3P4

Ingestion of 15 mg of 7,12-dimethylbenz(a)anthracene (DMBA) by lactating Sprague-Dawley rats increased the number of estrogen receptor sites in mammary cytosol fraction and decreased slightly the intrinsic association constant for the estradiol-receptor interaction. These effects were first seen 2 days after treatment, but there were no differences between control and DMBA-treated animals at 20 days after treatment. In the uterus there were no significant differences in the number of binding sites between control and DMBA-treated animals at any point during lactation.

Direct measurements of estradiol-17ß by a radioreceptor assay indicated reduced levels of the endogenous steroid in both mammary gland and uterus following DMBA treatment, but such a reduction could not account for the apparent increase in binding sites in mammary tissue. More likely, there was an increase in the proportion of epithelial cells to fat cells in the mammary glands of DMBA-treated rats, increasing the total amount of estrogen receptor in the gland.

¹ This work was supported by Grant A4670 from the National Research Council of Canada.

² To whom requests for reprints should be addressed.

Received 10/ 9/73. Accepted 12/10/73.

This article has been cited by other articles:

				A. B. Okey An Aryl Hydrocarbon Receptor Odyssey to the Shores of Toxicology: The Deichmann Lecture, International Congress of Toxicology-XI Toxicol. Sci., July 1, 2007; 98(1): 5 - 38. [Abstract] [Full Text] [PDF]