What are the effects of estrogen?

Estrogen is a hormone secreted from the ovaries and placenta. It can promote the development of other organs such as the ovaries, fallopian tubes, uterus, vagina, etc. to a certain extent. Under normal circumstances, it can promote better pregnancy among female friends. Once it is abnormal, it will affect normal fertility, and in severe cases it may even cause lifelong infertility.

1. The effect of estrogen on reproductive organs: Estrogen binds to target cell receptors on the ovaries, fallopian tubes, uterus and vaginal mucosa, causing increased synthesis of cellular DNA, RNA and protein, promoting cell division and growth, thereby causing the above-mentioned target organs to grow and develop and maintain their normal functions. If there is too little estrogen before puberty, the reproductive organs cannot develop normally; if there is too much estrogen, precocious puberty will occur.

(1) Ovaries: In addition to indirectly affecting ovarian activity through feedback regulation via the hypothalamus-pituitary gland, estrogen also has a direct effect on the ovaries. Experiments have shown that when ovarian tissue is cultured, estrogen can accelerate its growth, and estrogen can cooperate with the pituitary gland to secrete follicle-stimulating hormone (FSH) to promote follicle development. FSH, in conjunction with estrogen, induces and increases the luteinizing hormone (LH) receptors on the follicles, thereby increasing the sensitivity of the follicles to LH. It can be seen that the estrogen peak before ovulation, on the one hand, induces the appearance of the LH peak through positive feedback; on the other hand, it cooperates with FSH to increase the LH receptors on the follicles, which is conducive to the binding of LH to its receptors and induces ovulation. Therefore, estrogen is an indispensable regulatory factor for the development, maturation and inhibition of ovarian follicles.

(2) Fallopian tube: Estrogen promotes the proliferation of fallopian tube epithelial cells, enhances the activity of secretory cells, ciliated cells and smooth muscle cells, promotes fallopian tube movement, and is beneficial to the movement of sperm and eggs.

(3) Uterus: Estrogen promotes the development of the uterus and causes the endometrium to undergo proliferative changes. Estrogen also promotes the proliferation of uterine muscles and increases the content of myosin and myosin in muscle cells. Under the action of estrogen, the excitability of the uterine muscle increases, increasing the sensitivity of the uterine muscle to oxytocin. Under the action of estrogen, the cervix secretes a large amount of clear, thin mucus, in which the mucin is arranged longitudinally along the uterus, which is conducive to the passage of sperm.

(4) Vagina: Estrogen can shorten the division cycle of basal cells in the vaginal mucosa, cause epithelial cell proliferation, increase glycogen content, cause superficial cell keratinization, and cause mucosal thickening and wrinkling. Glycogenolysis makes the vagina acidic (pH 4-5), which is beneficial to the growth of vaginal lactic acid bacteria, thereby excluding the reproduction of other microorganisms. Therefore, estrogen can enhance the resistance of the vagina. With the changes in the human menstrual cycle and the animal motility cycle, the types of mucosal exfoliated epithelial cells shown in vaginal smears also show periodic changes. Under the action of estrogen, the smear is mainly composed of superficial cells. The higher the estrogen level, the more obvious the keratinization of the superficial cells.

2. The effect of estrogen on breast and secondary sexual characteristics: Estrogen stimulates the proliferation of mammary ducts and connective tissue, promotes breast development, and makes the distribution of body fat and hair have female characteristics, with a more dominant voice, a wider pelvis, and thicker buttocks.