Open AccessEstrogenic Potency of Oral Replacement Therapy Estimated by the Induction of Pregnancy Zone Protein
Author(s) -
Helgason S.,
Damber M.G.,
Schoultz B.,
Stigbrand T.
Publication year - 1982
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.3109/00016348209156956
Subject(s) - estrone , potency , estrogen , estriol , medicine , endocrinology , ethinylestradiol , pregnancy , estradiol valerate , blood proteins , estrogen therapy , population , chemistry , biology , in vitro , biochemistry , research methodology , environmental health , genetics
. The induction of a highly estrogen‐inducible plasma protein, the pregnancy zone protein/pregnancy associated α 2 ‐globulin (PZP/PAα 2 G), was used to design a sensitive method to quantify and compare the potency of various estrogens commonly used in clinical practice. Serum PZP levels were followed in 100 post‐menopausal women during 6 months' estrogen replacement therapy. Ethinyl estradiol caused more marked changes than the natural estrogens. Conjugated estrogens were more potent than estrone sulphate and estradiol‐17β which had similar values. Estriol, irrespective of daily dosage, exerted a negative effect. The following sequence of equipotency was calculated: ethinyl estradiol = 100 × conjugated estrogens = 450 × estrone sulphate = 500 × estradiol‐17β = 650 × estradiol valerate. These data were compared with other estimates of estrogenic potency from the literature. Compared with other clinical methods, PZP induction offers several advantages. Factors such as intestinal absorption, protein binding and intracellular metabolism are included in the net result of an increased protein synthesis which is easily followed in patients' sera during therapy.