(1) Natural estrogen can also easily be divided into the three types of estrogen: estradiol , estrone, and estriol.(2) Even though the ovaries cease producing estradiol , estriol continues to be made by the adrenal glands and in fat cells.(3) There were increases in blood levels of the estrogens, estradiol and estrone, and a reduction of the protective HDL cholesterol.(4) Steroid hormones such as progesterone, testosterone, and estradiol are derived from cholesterol, a major constituent of biomembranes.(5) The primary estrogen secreted by the ovary is estradiol , whereas that of the placenta is estriol.
