The distribution of oestradiol in plasma from postmenopausal women with or without breast cancer: relationships with metabolic clearance rates of oestradiol.
The distribution of oestradiol in plasma from postmenopausal women with or without breast cancer has been measured and related to the metabolic clearance rates of oestradiol (MCR-E2). All measurements were carried out preoperatively. No difference in the free fraction of oestradiol was found between women with breast cancer (1.8 +/- 0.4%, mean +/- SD) and normal women (1.6 +/- 0.3%). Approximately 40% of oestradiol in plasma was bound to albumin with 60% bound to sex hormone binding globulin (SHBG), but values were similar for women with or without breast cancer. Concentrations of total unconjugated oestradiol and free oestradiol (2.4 +/- 0.5 ng/100 ml and 44 +/- 12 pg/100 ml respectively, mean +/- SD, n = 9) were significantly higher in plasma from postmenopausal women with breast cancer compared with levels in plasma from normal postmenopausal women (1.8 +/- 0.5 ng/100 ml and 27 +/- 10 pg/100 ml, n = 8). A significant correlation was found between the free oestradiol fraction and MCR-E2 (r = 0.53, p less than 0.05). Correlations were also found between the fractions of oestradiol bound to albumin and MCR-E2 (r = 0.45). From correlations between the binding capacity of SHBG and MCR-E2 it appears that, for a given level of SHBG, MCR-E2 may be higher in women with breast cancer.
D001835:Body Weight; D001943:Breast Neoplasms / Q000097:blood / Q000378:metabolism*; D011232:Chemical Precipitation; D004958:Estradiol / Q000097:blood*; D005260:Female; D006801:Humans; D008593:Menopause; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D011485:Protein Binding; D011863:Radioimmunoassay; D012709:Serum Albumin / Q000378:metabolism; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism
D012709:Serum Albumin; D012738:Sex Hormone-Binding Globulin; D004958:Estradiol