Journal of Clinical Endocrinology & Metabolism, Vol 45, 429-434, Copyright © 1977 by Endocrine Society

ARTICLES

Estriol conjugates in human breast cyst fluid and in serum of premenopausal women

, and M Levitz

A sensitive method was developed for the assay of the four major estriol (E3) conjugates in human breast cyst fluid and in serum during the menstrual cycle. In the cyst fluid, estriol-3-sulfate (E3-3S) was found in each of ten samples, the concentrations ranging from 240-4310 pg/ml. Estriol-16-glucosiduronate (E3-16G) was detected in six samples at levels of 19-153 pg/ml; estriol-3-glucosiduronate (E3-3G) in five samples, 13-79 pg/ml and estriol-3-sulfate-16-glucosiduronate (E3-3S- 16G) in four samples, 28-152 pg/ml. Unconjugated estriol was found in three of the ten cases (12-30 pg/ml). Serum samples obtained in the follicular and luteal phases of the cycle from eight different subjects were assayed in the same way. There was considerable variation between subjects and many values were indistinguishable from zero. But preliminary data suggest that E3-3G is the predominant E3 conjugate in the serum and E3-3S-16G is quantitatively least important. It appears that E3 conjugates in the cyst fluid are not derived from the blood directly, but are produced locally from precursors which have not been identified.