Oestrogen is present in all vertebrates and some insects. It is a steroid hormone, produced in the ovaries, and it is most commonly recognised as a female sex hormone but it is also secreted in small amounts in men by the testis. It is part of the estrous cycle which helps to control the menstrual cycle. The primary function in women is in the development of the gonads, endometrium, mammary glands and that of female secondary sexual characters favouring for example, the osteoblastic activity. It can be used as a birth control method and is in the combined pill. It is also present during pregnancy when it is produced by the placenta.
- ↑ Litwack, G., Vol. 71, 2005, Vitamins and Hormones. Burlington: Elsevier
- ↑ Follicle stimulating hormone | You and Your Hormones from the Society for Endocrinology [Internet]. Yourhormones.info.[cited 6 December 2018]. Available from: http://www.yourhormones.info/hormones/follicle-stimulating-hormone/