Estrogen #2 Essential Blood Test Panel

Estrogen #2 Essential Panel includes:

Estrogen is a group of hormones that are primarily responsible for the development of female sex organs and secondary sex characteristics. Estrogen is one of the major female sex hormones, but small amounts are found in males. In women, follicular stimulating hormone (FSH; produced by the pituitary gland) stimulates cells (follicles) surrounding the eggs in the ovaries, thus causing them to produce estrogen. When the estrogen levels reach a certain level, the pituitary produces a surge of luteinizing hormone (LH), which eventually causes the release of the egg, which begins the preparation for fertilization.

The three main estrogen fractions are: estrone (E1), estradiol (E2), and estriol (E3).

Estrone (E1) is the major estrogen after menopause. Derived from metabolites from the adrenal gland, it is often made in adipose tissue (fat).

Estradiol (E2) is produced in women mainly in the ovary. The testes and adrenal glands are the principal source of estradiol in men. In women, normal levels of estradiol provide for proper ovulation, conception, and pregnancy, while also promoting healthy bone structure and regulating cholesterol levels.

Estriol (E3) is the major estrogen in pregnancy, with relatively large amounts that are produced in the placenta (from precursors produced by the fetal adrenal glands and liver). Estriol levels will start to rise in the eighth week of pregnancy and continue to rise until shortly before delivery. Serum estriol that is circulating in maternal blood is quickly cleared out of the body. Each measurement of estriol is a snapshot of what is happening with the placenta and fetus, although there is also natural daily variation in the estriol level.

Follicle-stimulating hormone (FSH) is made by the pituitary gland located in the brain. Control of FSH production is a complex system that involves hormones produced by the gonads (ovaries or testes), the pituitary, and the hypothalamus. In women, FSH will stimulate the growth and maturation of ovarian follicles (eggs) during the follicular phase of the menstrual cycle. The menstrual cycle is divided into two phases, the follicular and the luteal, by a mid-cycle surge of FSH and luteinizing hormone (LH). Ovulation occurs shortly after the mid-cycle surge of hormones. During the follicular phase, FSH initiates production of estradiol by the follicle, and the two hormones will work together in the further development of the egg follicle. During the luteal phase, FSH stimulates production of progesterone. Both estradiol and progesterone help the pituitary to control the amount of FSH produced. FSH also facilitates the ability of the ovary to respond to LH. At the time of menopause, the ovaries will stop functioning and FSH levels rise. In men, FSH stimulates the testes to produce mature sperm and also promotes production of androgen binding proteins. FSH levels remain relatively constant in males after puberty.

Luteinizing hormone (LH) is produced by the pituitary gland located in the brain. Control of LH production is a complex system that involves hormones produced by the gonads (ovaries or testes), the pituitary, and the hypothalamus. Menstrual cycles are divided into two phases, the follicular and luteal, by a mid-cycle surge of follicle-stimulating hormone (FSH) and LH. High levels of LH and FSH, at mid-cycle, triggers ovulation. LH also stimulates the ovaries to produce steroids, primarily the steroid estradiol. Estradiol and other steroids help the pituitary regulate the production of LH. At the time of menopause, the ovaries stop functioning and LH levels will rise. In men, LH stimulates the Leydig cells in the testes in order to produce testosterone. LH levels are relatively constant in men after puberty. Testosterone provides negative feedback to the pituitary and the hypothalamus, helping regulate the amount of LH secreted.