Chemical Messengers

Question 1

What are hormones?

Answer 1

substances synthesized and released by a cell that in turn regulates the function of their target organ/cell

Question 2

How are hormones classified? (4)

Answer 2

chemical structure, method of delivery, cell type secretion, mechanism of hormone action

Question 3

What are the different hormone structures? (4)

Answer 3

proteins/peptides, steroids, amines, eicosanoids

Question 4

What is gonadotrophin releasing hormone (GnRH?)

Answer 4

starting point for release and manufacturing of gonadotrophs and sex hormones

released into portal blood system within median eminence

Question 5

What is the Luteinizing Hormone (LH?)

Answer 5

synthesized by gonadotrophs in anterior pituitary

acts on the support cells of ovarian follicules to regulate steroidogenesis and stimulate ovulation

Question 6

What are steroids?

Answer 6

lipid molecule hormones, hydrophobic, can pass into cell because of similar lipid bilayer

Question 7

What does estrogen do? (5)

Answer 7

sexual differentiation of the brain, development of female secondary sex characteristics (ducts, etc), maintenance of sexual behavior, growth of uterine lining, folliculogenesis

Question 8

What is premarin?

Answer 8

medication for estrogen and menupause, comes from mare pee

Question 9

What does progesterone (progestins) do? (3)

Answer 9

mammary gland development, preparation of reproductive tract for gamete transport and implantation of zygote, maintenance of pregnancy

Question 10

What is mifepristone?

Answer 10

progesterone blocker, abortions

Question 11

What do androgens do? (4)

Answer 11

differentiation and development of gonads, development of male secondary sex characteristics, spermatogenesis, maintenance of sexual behavior

Question 12

What is striant?

Answer 12

drug treatment for low testosterone

Question 13

What is the importance of cholesterol?

Answer 13

all steroids are derived from cholesterol as a starting point of reactions

Question 14

Why do lipids need carrier transport in the blood?

Answer 14

they are transported as lipoproteins because they are hydrophobic

Question 15

What is LDL?

Answer 15

complex in blood carrying cholesterol

Question 16

What is HDL?

Answer 16

picks up cholesterol to become LDL

Question 17

What is steroidogenesis?

Answer 17

production of steroid hormones necessary for reproduction

Question 18

What are other (non gonad) sources of sex steroids?

Answer 18

estrogens: placenta during pregnancy, adrenals, adipose tissue

testosterone: adrenals, adipose tissue (both in males, menopausal females, pre pubitals)

Question 19

What do eicosanoids (prostaglandins) do? (5)

Answer 19

inflammation control

rupture of mature follicule during ovulation, regulation of menstrual bleeding, enhance contractions, luteolysis of CL

Question 20

What is prostaglandin?

Answer 20

inflammation medication, can inhibit ovulation over time because it stops a pathway

Question 21

What are the mechanisms of hormone action? (3)

Answer 21

concentration, spacial distribution (endocrine vs neurocrine vs paracrine), specific hormones binding to special proteins

Question 22

What do receptors do?

Answer 22

bind to specific hormones, recognition

changes the “energy” of hormones binding into a signal within the cell, which results in modification of cell function

Question 23

What kind of hormone do cytosolic receptors bind to?

Answer 23

steroids (because they are in the cytosol, able to get past the membrane)

Question 24

How does a hormone elicit a cell action? (diagram) (3 steps)

Answer 24

1. hormone binds to receptor
   - hormone is primary signal (messenger)
2. transduction of signal through the effector molecule
   - effector associates with receptor, receptor is activated, a second signal is produced
   - cyclic amp regulates it
3. Second messenger activation of downstream signals
   - must continue to propogate signal to downstream targets, regulate multiple processes in the cell

Question 25

Why is phosphorylation important in hormone signaling?

Answer 25

it is involved in signaling pathways, need it to remove or add stuff to ion for it to continue down the pathway signal

Question 26

If a receptor is mutated and can’t see a hormone (ex. testosterone) what happens?

Answer 26

higher output of GnRH, FSH, LH
hypo development of gonads, gonadal functions

Question 27

What molecule must be bound to steroids in the bloodstream?

Answer 27

steroid hormone binding globulin (SHBG)

Question 28

CYP19 is the same thing as what?

Answer 28

aromatase

Question 29

What do G Protein coupled receptors (GPCR) do?

Answer 29

extracellular domain that binds to gonadotrophin hormones
they have a tail that interact with G proteins

Question 30

What are the cycle steps of circulating steroids? (7)

Answer 30

1. release of circulating steroid from steroid hormone binding globulin (SHBG) and diffusion into cell
2. steroids bind to cytosolic receptor
3. Ligand receptor interaction causes shape change, activates receptor
4. Lingand-hormone-receptor enters nucleus
5. Dinerization of steroid receptor in specific binding cites (response element) on DNA promoter
6. Transcription
7. Synthesis of new protien

Question 31

What is pathophysiology?

Answer 31

study of basis of disease where reproduction is compromised

Question 32

What are some anatomical problems in pathophysiology?

Answer 32

embryogenesis problems, sex chromosome abnormalities, bad hormone secretion/recognition

Question 33

What are some endocrine problems in pathophysiology?

Answer 33

excess/inadequate production/secretion, hyper/hypo sensitivity of target, dysfunction of gland

Question 34

What is pseudohermaphroditism/Leydig cell hypoplasia?

Answer 34

poor development of testis and external genitalia, insensitive to LH, lack of properly expressed receptors

Question 35

What is male precocious puberty/testotoxicosis?

Answer 35

onset of puberty