Ovarian daily production of Estradiol per day is 70-500 mcg (0.5 mg)
After menopause most endogenous estrogen is produced by conversion of Androstendione via adrenal cortex, to Estrone by peripheral tissues
Estrogen is bound to SHBG (sex hormone binding globulin)
Estriol is major urinary metabolite
Single intramuscular injection of estrogen is metabolized over several weeks
Estradiol and Estrone are reversibly converted, hence the reason why women who have high body fat (indicative of high Estrone) often are
symptom free
To date two estrogen receptors have been identified which vary in proportion from tissue to tissue
Carbamazepine (Tegretol) and St. John’s Wort decrease plasma estrogen
Inhibition of CYP3AY such as Erythomycin, Ketoconazole (Nizoral), grapefruit juice – all increase plasma concentration of estrogen
Estrogen increases TBG – hence, may require low dose physiologic thyroid replacement
