Reproductive Hormones and testing

Estrogens are responsible for

development and maintenance of female sex organs + secondary sex characteristics

Progesterone is involved in

• regulation of menstrual cycle

• breast + uterine development

• maintenance of pregnancy

T or F: Estrogen can affect calcium homeostasis

True (beneficial effect on bone mass)

Estrogens increase the plasma concentration of __

SHBG, corticosteroid binding globulin, thyroxine binding globulin

3 active forms of estrogens

• Estrone (E1)

• Estradiol (E2)

• Estriol (E3)

Estrogen is secreted primarily in __ (4 places)

• Ovarian follicles (E2)

• corpus luteum

• placenta (during pregnancy, E3)

• adrenal glands and testes (small amounts)

Ovary makes estrogen via

aromatization of androgens

Healthy ovary makes __

• estrogens

• progestagens

• androgens

What are the primary secretory products of the ovary

E2 and progesterone

Can ovaries make glucocorticoids and mineralocorticoids (cortisol/aldosterone)

No because they lack the necessary enzymes

What is the most potent natural estrogen and where is it made

• Estradiol (E2)

• mainly by testes in males and ovaries in nonpregnant females

• also to a lesser degree by luteum, placenta, adrenals

T or F: 97% of estradiol (E2) circulates mainly bound to SHBG

true

Estradiol (E2) is responsible for the development of female secondary sex characteristics. List how

• causes proliferation of the endometrium

• increases thickness of vaginal epithelium

• increases vascularity of cervix

• increases cervical mucous elasticity to allow sperm penetration

• dilates cervial os

How much estradiol (E2) circulates free

2-3%

Progesterone is made by

• ovary

• corpus luteum (main source in nonpregnant)

• placenta (main source in pregnancy)

• adrenal cortex (minor in males + females)

• testes in men

Function of progesterone

• prepare for and maintain pregnancy by thickening and vascularizing endometrium

• induce differentiation of estrogen primed ductal breast tissue

• support breast secretory function during lactation

• increase basal body temp

T or F: Progesterone is a precursor to estrone, testosterone, and estradiol

True

In females, testosterone is made by

• adrenal glands

• ovaries

• through peripheral metabolism of weak adrenal androgens

What is the estradiol (E2) precursor in females

testosterone

Ovum

female egg (gamete) made by the ovary

How many primordial follicles does ovaries have

400,000

Length of a typical menstrual cycle

28 days ± 1 to 3 days

3 phases of female menstrual cycle

1. Follicular phase

2. ovulatory phase

3. luteal phase

In the menstrual cycle, the hypothalamus stimulates the anterior pituitary by making and releasing

Gonadotropin-releasing hormone (GnRH)

What does gonadotropin-releasing hormone do?

• stimulates release of FSH and LH from the anterior pituitary

• triggers LH surge prior to ovulation

In regards to the menstrual cycle, what 2 hormones are made by the anterior pituitary after stimulation by Gonadotropin releasing hormone (GnRH)

• Follicle stimulating hormone (FSH)

• luteinizing hormone (LH)

What does FSH do during the follicular phase a few days prior to day 1 of cycle

FSH initiates growth and maturation of a few follicles

Follicles secrete increasing amounts of __ as they mature in size

estrogens

Follicle stimulating hormone (FSH) rises at midcycle due to __

decreasing E2

FSH is suppressed during the luteal phase by __

negative feedback from E2

At the end of your cycle, you see a slight rise in __ to start off the follicular maturation for the next cycle

FSH

Luteinizing hormone secretion is suppressed during follicular phase by __

negative feedback from E2

As E2 increases from the developing follicle, E2 effect becomes a positive feedback that will __

increase the release of GnRH and increased sensitivity of anterior pituitary to GnRH causes a midcycle surge of LH

Luteinizing hormone (LH) stimulates the developing corpus luteum to make __

progesterone

During the luteal phase, progesterone and E2 will cause a negative feedback that suppresses

LH (during luteal phase)

Do the LH levels begin to rise slowly early in the follicular phase

Yes (usually 1-2 days after rise in FSH)

LH stimulates synthesis of __

androstenedione and testosterone which are converted to estrogens

What is the rate of sex steroid production like during the 1st half of the follicular phase

slow and constant

7-8 days before the ovulatory phase, the follicle produces increasing amounts of __ which cause a LH surge (max level of LH = 1 day before ovulation)

estradiol (E2)

What is day 1 of the normal menstrual cycle

first day of bleeding

What begins the follicular phase

Begins with the initiation of the follicular growth (during the last few days of the previous luteal phase)