Difference Between Estrogen and Progesterone

Main Difference – Estrogen vs Progesterone

Estrogen or Oestrogen and Progesterone are the two types of female sex hormones secreted by the ovaries. Estrogen is mainly secreted by the theca interna of the ovarian follicle. Progesterone is mainly secreted by the corpus leteum. The main difference between estrogen and progesterone is that estrogen controls the formation and maintenance of secondary female sex characteristics whereas progesterone controls the growth and maintenance of endometrium of the uterus. Estrogen also plays an important role during menstrual cycle and pregnancy. Estrogen levels are increased during the period of ovulation while progesterone levels are increased during the release of the egg.

Key Areas Covered

1. What is Estrogen/Oestrogen
– Definition, Production and Secretion, Role
2. What is Progesterone
– Definition, Production and Secretion, Role
3. What are the Similarities Between Estrogen and Progesterone
– Outline of Common Features
4. What is the Difference Between Estrogen and Progesterone
– Comparison of Key Differences

Key Terms: Endometrium, Estrogen, Female Sex Hormones, Placenta, Pregnancy, Progesterone, Oestrogen, Ovaries

What is Estrogen/Oestrogen

Estrogen or oestrogen refers to a steroid hormone that is important in the reproductive development in females. It represents a group of hormones including estrone, estradiol, and estriol. It is mainly produced in the ovaries, grape-sized glands located on either side of the uterus. Some estrogens are produced by the fat cells of the adrenal gland. The secretion of estrogen is regulated by follicle-stimulating hormone (FSH). The main function of estrogen is to develop secondary sex characteristics in females at puberty. Some of those characteristics are breasts, wider hips, armpit hair, and pubic hair. Estrogen is involved in the formation of endometrium at the beginning of the menstrual cycle. If the egg is not fertilized, the levels of estrogen decrease sharply, initiating menstruation. Placenta produces estriol during pregnancy. Estrogen also controls lactation. The structures of estradiol and progesterone are shown in figure 1.

Main Difference - Estrogen vs Progesterone

Figure 1: Estradiol and Progesterone

Estrogen also plays an important role in the bone resorption by effectively breaking down and rebuilding bones.

What is Progesterone

Progesterone refers to a steroid hormone that prepares the uterus for pregnancy. It is produced by both ovaries and placenta. Adrenal glands also produce some amount of progesterone. The main function of progesterone is to prepare the body for the conception and pregnancy. The corpus luteum, the ovarian follicle of the luteal phase, produces progesterone during pregnancy. The production and secretion of progesterone are regulated by luteinizing hormone (LH). The hormone changes during the menstrual cycle are shown in figure 2.

Difference Between Estrogen and Progesterone

Figure 2: Menstrual Cycle

During the second half of the menstrual cycle, progesterone induces the endometrium to produce special proteins that nourish the fertilized egg.

If implantation does not occur, the levels of progesterone decrease along with estrogen levels. During the pregnancy, the placenta also produces progesterone. Hence, the levels of progesterone remain high throughout the pregnancy. Progesterone also stimulates the milk-production in the breast.

Similarities Between Estrogen and Progesterone

Estrogen and progesterone are the two types of female sex hormones.
Both estrogen and progesterone are steroid hormones.
Both estrogen and progesterone are secreted during the menstrual cycle.
Both estrogen and progesterone play a role during pregnancy.
Both estrogen and progesterone are a part of the contraceptive mix of birth control pills.

Definition

Estrogen: Estrogen refers to a steroid hormone that is important in the reproductive development in females.

Progesterone: Progesterone refers to a steroid hormone that prepares the uterus for pregnancy.

Production

Estrogen: Estrogen is produced by the growing Grafian follicle.

Progesterone: Progesterone is produced by the corpus luteum.

Secretion

Estrogen: Estrogen is secreted by ovaries prior to ovulation. It is also produced by the placenta during pregnancy.

Progesterone: Progesterone is secreted by the ovaries after the ovulation. It is also produced by the placenta during pregnancy.

Regulation

Estrogen: The secretion of estrogen is regulated by FSH.

Progesterone: The secretion of progesterone is regulated by LH.

Role

Estrogen: Estrogen is involved in the formation and maintenance of secondary sex characteristics. It is also important in bone resorption.

Progesterone: Progesterone is involved in the formation and maintenance of endometrium and uterus.

During Pregnancy

Estrogen: Estrogen is involved in the enlargement of the uterus and breasts during pregnancy.

Progesterone: Progesterone is involved in the reduction of contractility of the uterus and stimulates the growth of mammary glands.

Conclusion

Estrogen and progesterone are the two female sex hormones. Both estrogen and progesterone are produced and secreted by the female reproductive system. Estrogen is involved in the formation and maintenance of secondary sex characteristics in females. Progesterone is involved in the maintenance of the conditions in the uterus. The main difference between estrogen and progesterone is the role of each hormone in the body.

Reference:

1. Bradford, Alina. “What Is Estrogen?” LiveScience, Purch, 2 May 2017, Available here.
2. “Progesterone.” HealthyWomen, Available here.

Image Courtesy:

1. “Progesterone” By Rhododendronbusch – Own work (Public Domain) via Commons Wikimedia and “Estradiol” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia [Merged]2. “MenstrualCycle” By Chris 73 / Wikimedia Commons (CC BY-SA 3.0) via Commons Wikimedia