Estrogen-binding protein in blood and follicular fluid, and its biochemical properties in human females.
Testosterone-estradiol binding globulin (TeBG) has been known to have specific binding to estradiol (E2) in blood, however an unknown binding protein having higher affinity to E2 than TeBG is thought to exist in blood. Therefore blood serum and follicular fluid were collected in normal females. Ammonium sulfate precipitation showed different maximum bound ratio between E2BP and TeBG. Concanavalin A (Con-A) Sepharose adsorption analysis showed that the Con-A-bound phase demonstrated estradiol-binding protein (E2BP). Isoelectric focusing showed TeBG in pH 4.9 and E2BP in pH 3.9. The substance giving the peak at pH 3.9 has a high affinity to dehydroepiandrosterone sulfate and E2, but the substance with peak at pH 4.9 shows a high affinity to 5-dihydrotestosterone and testosterone. E2BP changed concomitantly with total E2 in blood in the menstrual cycle, but in follicular fluid E2BP was found only in small amounts. It consisted of two components, one protein with low affinity binding and the other with high affinity binding. These results suggest that E2BP exists as a specifically bound fraction to E2, while TeBG, as a nonspecifically bound fraction to E2, is not directly involved in the E2-related biological function.
Saito
N
N
Department of Obstetrics and Gynecology, Yamagata University School of Medicine, Japan.
Kanasugi
H
H
Kimura
K
K
Suzuki
T
T
Komiya
Y
Y
Ogawa
H
H
Hiroi
M
M
D000328:Adult; D001774:Blood Chemical Analysis; D001826:Body Fluids / Q000032:analysis*; D005260:Female; D006801:Humans; D008597:Menstrual Cycle / Q000187:drug effects*; D012738:Sex Hormone-Binding Globulin / Q000032:analysis*
D012738:Sex Hormone-Binding Globulin