<prompt> Most potent estrogen is -Estrone ElEstradiol E2EstriolE3Etisterone enanthate  <response>: Ans. is b i.e., Estradiol E2 Estrogeno Natural oestrogens are Cl 8 steroids, the main source of which are the theca and granulosa cells of the Graafian follicles and corpus luteum, while the adrenal cortex is the secondary source of supply.o Oestrogen is secreted as oestradiol. It is bound to albumin 30 and sex-hormone-binding globulin SHBG, 69, and only 1 is biologically active.o It acts by binding to cytoplasmic receptors in the cells.o It is inactivated by the liver and excreted as conjugates of oestrone, oestradiol and oestriol in the urine and bile 85 in urine, 10 in faeces.o Estradiol is ten times more potent than estrone, which is ten times more potent than estriol. Thus potency of estroogens is as follows:Estradiol estrone estriol.Major estrogen during:o Reproductive age group - estradiolo Post menopausal period - estroneo Pregnancy - estriol 