Estrone

Estrone is a steroid like estriol and estradiol, belonging to the class of estrogens. The estrogens are involved in the development of female sex organs and secondary sex characteristics. Before the ovum is fertilized the main action of the estrogens is on the growth and function of the reproductive tract in order to prepare it for the fertilized ovum. During the follicular phase of the menstrual cycle the estrone level shows a slight increase.