Summary
The direct influence of the three basic natural estrogens, estrone, 17 beta-estradiol
and estriol, on DNA synthesis in human normal mammary epithelial cells was investigated
in organ culture during 7 days, and was assessed by autoradiography. A threshold concentration
of I.O. ng per ml was needed to elicit a significant stimulation by estradiol and
estriol. No significant increase in the incorporation of tritiated-thymidine could
be obtained with estrone in the same conditions. These observations are in keeping
with the hypothesis put forward by Gurpide, Tseng and Gusberg (1977) that estrone per se might be devoid of any direct estrogenic effect.
Key-Words:
Breast
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Estrone
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Estradiol
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Estriol
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Organ Culture
