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Flashcards in Gonadal hormones Deck (42)
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1

reproductive hormone produced by hypothalamus & its target

produces Gonadotropin (GNRH) & acts on the pituitary

2

pituitary response to GnRH

secretes Luteinizing hormone (LH) & Follicle stimulating hormone (FSH) & acts on male testes & female ovaries

3

FSH on male

FSH acts on germinal stem cells to make sperm

4

LH on males

LH acts on Leydig cells to form testosterone

5

FSH on females

FSH acts on follicles to facilitate maturation of ovum

6

LH on females

LH acts to start luteal phase where ovulation occurs & corpus luteum forms

7

Feedback

estrogen/testosterone shuts down the release of GnRH & LH & FSH
exception! - female menstrual cycle where estrogen exerts a positive feedback mechanism

8

Male testosterone

major androgen in males
made in Leydig cells through LH action
transported by sex hormone binding protein (SHBG 45%) & albumin (50%) only 3% is free (most active)

9

feedback on male testosterone

testosterone & inhibin (!!)
has circadian rhythm- highest concentration at 8 am

10

Testosterone cellular mechanism

enters cell & converts to dihydrotestosterone (DHT) --> complexes with intracellular receptor --> complex moves to nucleus & nuclear receptors --> binding to DNA leads to protein synthesis & cell growth

11

enzyme that converts testosterone to DHT

5-alpha reductase
very prevalent in male scrotal skin

12

testosterone actions before puberty

quiet actions (almost nothing significant)

13

testosterone actions after puberty

large increases in testosterone
secondary sexual characteristics- facial hair, muscles, voice change, elongation of bones
mood swings

14

testosterone in male adults

modest testosterone
enough to maintain secondary sexual characteristics
as prostate enlarges, can have hair loss
concern about hypogonadism

15

hypogonadism in males

hypergonadotropic hypogonadism
hypogonadotropic hypogonadism

16

Hypergonadotropic hypogonadism lab values in men

increased FSH & LH
decreased testosterone

17

types of hypergonadotropic hypogonadism in men

Klinefelter syndrome- extra chromosome 47
Testicular Feminization syndrome- androgen resistance
5-alpha reductase deficiency - genotype XY, raised female then at puberty no period & discover male genetics
myotonic dystrophy- autosomal dominate
testicular injury &/or infection - mumps, viral, HIV
Sertoli cell only syndrome- lack germ cells

18

Hypogonadotropic hypogonadism in men

decrease FSH, LH, & Testosterone

19

types of hypogonadotropic hypogonadism in men

Kallman's syndrome- inherited x-liked recessive trait, hypogonadism & no sense of smell
Hyperprolactinemia- increased prolactin
age- decreased testosterone after 30
pituitary disease- acquired hypogonadism, pituitary tumors, surgery etc

20

replacement therapy in males

complications of polycythemia, prostate cancer risk, sleep apnea, breast formation
need to monitor FSH, LH, testosterone, PSA (prostate specific antigen), CBC, lipid panels & monitor semen indices

21

female hormones after puberty

FSH & LH lead to secondary hormones of estrogen, progesterone & androgens from ovaries

22

Estrogens' general effect

promote breast, uterine, & vaginal development
affects skin, vascular smooth muscles, bone cells & CNS

23

Progesterone

made by corpus luteum
readies the endometrium for implantation of embryo
cervical mucus thickens & temperature rises

24

Androgens in females

androstenedione, dehydroandrostenedione, testosterone, DHT
all produced even after menopause

25

other ovary hormones

inhibin A & inhibin B (!)

26

female menstrual cycle

FSH high initially then decreases - controls first half of menstrual cycle
LH surge (ovulation)- makes follicle release an egg & rises body temp
progesterone - rises after LH surge & decreases before FSH

27

hormone feedback in females

inhibin A & B inhibits FSH!
estrogen positive feedback for LH surge & ovulation

28

transport molecule for estrogen & testosterone?

sex/steroid hormone binding globulin SHBG

29

hormones after menopause

FSH rises while LH may or may not
estrogens are decreased
adrenal androgens are still produced

30

hypogonadism in females

hypogonadotropic hypogonadism & hypergonadotropic hypogonadism