Lecture 4- Reproductive endocrinology

Question 1

… converts testosterone into dihydrotestosterone

Answer 1

5 alpha reductase

Question 2

3 major classes of sex steroids, they differ with respect to the number of carbons they contain…

Answer 2

1. pregnanes (21C)
2. androgens (19C)
3. estrogens (18C)

Question 3

… converts testosterone to estradiol

Answer 3

aromatase

Question 4

GnRH secretion from the hypothalamus is … due to the activity of pacemaker neurons that spontaneously produce action potentials resulting in secretory bursts of GnRH

Answer 4

pulsatile

Question 5

… is more potent than DHEA and androstendione

Answer 5

testosterone

Question 6

the 3 types of cells in the testis are

Answer 6

spermatic
leydig
sertoli

Question 7

spermatic cells include mitotically active …. and meiotic …

spermatogenesis proceeds as the spermatic cells move through the wall of the seminiferous tubules from the… towards the…. and…

Answer 7

spermatogonia

spermatocytes

basal lamina

apical surface

lumen

Question 8

… cells lie outside of the seminiferous tubules. They synthesize T in response to LH

Answer 8

Leydig

Question 9

In the gonad, T regulates…

In the brain, T regulates… (after being aromatized to…)

Elsewhere in the body, T regulates

Answer 9

spermatogenesis

sexual behavior

(E2)

secondary sexual characteristics

Question 10

… cells are the epithelial cells lining the seminiferous tubules. In response to FSH, they regulate spermatogenesis and produce the peptide hormone inhibin

Answer 10

Sertoli (sustentacular)

Question 11

Inhibin has negative feedback actions on…

Answer 11

FSH secretion

Question 12

Sertoli cells also produce an androgen binding protein that helps sequester T in the testis so spermatogenesis is…

Answer 12

continuous

Question 13

Sertoli cells also secrete tubular fluid to provide…

Answer 13

nutrient support for spermatozoa

Question 14

LH stimulates… synthesis by… cells

Answer 14

T

Leydig

Question 15

FSH stimulates… cells to regulate… and synthesize …

Answer 15

sertoli
spermatogenesis
inhibin

Question 16

3 other effects of T that are also important in females

Answer 16

regulate bone growth

stimulate muscle growth

stimulate erythropoesis

Question 17

3 reproductive system effects of T

Answer 17

sexual differentiation

secondary sex characteristics

stimulate erythropoesis

Question 18

DHT is non- … and more potent than…

Answer 18

aromatizable

Testosterone

Question 19

… are used to treat breast and prostate cancers

Answer 19

aromatase inhibitors

Question 20

…. used to treat hair loss

Answer 20

5 alpha reducatase (this is because DHT promotes hair loss in male pattern baldness)

Question 21

4 important cells of ovary

Answer 21

oocytes
theca cells
granulosa cells
luteal cells

Question 22

Each…. is enclosed in a follicle

Answer 22

oocyte

Question 23

Are there oogonia after birth?

Answer 23

No. All oocytes are arrested in prophase of meiosis I

Question 24

… cells are on the outside of the follicle

Answer 24

Theca (location and function is analogous to leydig cells)

Question 25

... cells are the epithelial cells of the follicle. They produce fluid, regulate maturation and can start as a single layer and become several layers thick

Answer 25

granulosa (analogous to the sertoli cells)

Question 26

.... cells are present after ovulation when the theca and granulosa cells are transformed into the corpus lutem

Answer 26

luteal

Question 27

Theca cells synthesize .... in response to... which then diffuses into granulosa cells

Answer 27

androstenedione LH

Question 28

In response to ..., granulosa cells convert androstenedione to.... which is converted to....

Answer 28

FSH estrone estradiol (E2)

Question 29

5 effects of Estradiol (E2)

Answer 29

stimulates granulosa cell function and replication regulates oocyte development reg. female secondary sex charac. regulator of bone turnover and arterial fxn typically inhibits GnRH and LH secretion

Question 30

In response to FSH, granulosa cells will also secrete.... which has a negative feedback effect on the anterior pituitary

Answer 30

inhibin

Question 31

... surge stimulates ovulation

Answer 31

LH

Question 32

Day 1-2 in the ovarian cycle is when there is a ... rise and ... development

Answer 32

gonadotropin follicular

Question 33

Day 3-5 in the ovarian cycle, there is an increase in... and... and there is .... selection

Answer 33

E2 inhibin dominant follicle

Question 34

Day 6-8 in the ovarian cycle, ... decreases, there is an ... peak, and an ... surge (positive feedback action of E2 on GnRH and LH)

Answer 34

FSH E2 LH

Question 35

Day 9-11 in the ovarian cycle, ... is completed, ... and ... formation

Answer 35

meiosis I ovulvation CL

Question 36

Day 12-13, there is an increase in ... and ... and ... are inhibited

Answer 36

E2 P gonadotropins

Question 37

Day 14-16 of the ovarian cycle, there is ... regression, a decrease in .... and gonadotropins rise

Answer 37

CL | steroids

Question 38

The menstrual or uterine cycle follows or parallels the ... cycle

Answer 38

ovarian

Question 39

menstrual phase begins when ... regresses and the steroid support for uterine endometrium is lost

Answer 39

CL

Question 40

differentiation of gonadal sex is determined by the presence of a gene on the Y chromosome that encodes for ... protein

Answer 40

SRY

Question 41

.... directs the indifferent gonad to become a testis

Answer 41

SRY

Question 42

the fetal testis produces 2 hormones that regulate sexual differentiation of the internal genitalia--

Answer 42

Testosterone and | mullerian inhibiting substance (MIS)

Question 43

in a develping male, T stimulates proliferation of the ... duct system that will become the tubules associates with the male reproductive tract and MIS causes...

Answer 43

wolffian mullerian duct system to regress

Question 44

in a developing female, there is no significant production of gonadal steroids. Absence of .... causes regression of the .... duct system and absence of ... results in proliferation or maintenance of the ... duct system that becomes the tubules of the female reproductive tract

Answer 44

Testosterone Wolffian MIS Mullerian

Question 45

external genitalia: the early embryo and fetus are undifferentiated up to ... weeks

Answer 45

9

Question 46

.... is when there is an adrenal enzyme deficiency resulting in excess production of adrenal androgens

Answer 46

congenital adrenal hyperplasia

Question 47

an example of CAH is when there is a mutation of ... causing a female (XX genotype) to have a male phenotype

Answer 47

21 alpha hydroxylase

Question 48

In ... deficiency (also called guevodoces) they have an XY genotype but phenotype at birth is female

Answer 48

5 alpha reductase

Question 49

in 5 alpha reductase deficiency, the phenotype at birth is female because development of the penis, scrotum, and prostate gland are ... dependent

Answer 49

DHT

Question 50

Do people who suffer from CAH have both male and female parts internally?

Answer 50

yes because of testosterone

Question 51

in 5 alpha reductase deficiency, they will lack male genitalia but increased ... secretion with onset of puberty completes differentiation

Answer 51

T

Question 52

Testicular feminization or androgen insensitivity is a ... genotype and ... phenotype.

Answer 52

male | female

Question 53

in pregnancy, the CL regresses after... months and ... supports luteal steroidogenesis

Answer 53

3 | hCG

Question 54

... stimulates growth of myometrium

Answer 54

placental E2

Question 55

... reduces uterine contractility and stimulates vasodilation

Answer 55

placental P