caa a22 4500 386389470 CHVBK 20180307112109.0 cr unu---uuuuu 161130s1989 xx s 000 0 eng 10.1017/S0269727000010642 doi S0269727000010642 pii (NATIONALLICENCE)cambridge-10.1017/S0269727000010642 Oestrogens in breast tumours and fat [Elektronische Daten] The levels of endogenous steroids in the target tissues are thought to be more closely related to the biological effects than their concentrations in plasma. Therefore studies on oestrogen levels in malignant and non-malignant breast tissues (expressed per g wet weight) were conducted and the following conclusions were drawn: (1) malignant tumours contained higher oestradiol levels than normal or benign breast tissues, whereas oestrone levels were more comparable; (2) in contrast to the large decrease in plasma concentrations after menopause, the levels of oestradiol in tumours and in normal breast tissue did not change with advancing age; (3) the oestradiol levels in breast tissues were lower than in uterine tissues, particularly in women before menopause; oestrone levels were very similar in all tissues studied; (4) the mean oestradiol level was higher in oestrogen-receptor-positive tumours, but no correlation between the two parameters was found; (5) preliminary results indicated lower oestradiol levels in tumours obtained from countries with a lower incidence of breast cancer; (6) as far as available, oestrone levels were comparable and those of oestradiol were lower in fat tissues than in breast tumours; (7) neither in vitro studies with breast tumours, nor in vivo results using myometrial tissues support a prominent role of the metabolism of oestrogens at the 16α-position in the development of tumours; (8) the role of local factors in the production, retention and metabolism of oestradiol in the breast remains to be elucidated. Copyright © Royal Society of Edinburgh 1989 Peripheral Synthesis and Endogenous Oestrogens nationallicence Thijssen J. H. H. Department of Endocrinology, University Hospital, Catharijnesingel 101, 3511 GV Utrecht, The Netherlands Blankenstein M. A. Department of Endocrinology, University Hospital, Catharijnesingel 101, 3511 GV Utrecht, The Netherlands Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences Royal Society of Edinburgh Scotland Foundation 95(1989), 161-168 0269-7270 95<161 1989 95 PRB https://doi.org/10.1017/S0269727000010642 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0269727000010642 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Thijssen J. H. H. Department of Endocrinology, University Hospital, Catharijnesingel 101, 3511 GV Utrecht, The Netherlands NATIONALLICENCE 700 1- Blankenstein M. A. Department of Endocrinology, University Hospital, Catharijnesingel 101, 3511 GV Utrecht, The Netherlands NATIONALLICENCE 773 0- Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences Royal Society of Edinburgh Scotland Foundation 95(1989), 161-168 0269-7270 95<161 1989 95 PRB CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge