Hormones of the Reproductive Axis

Question 1

does the repro system respond fast or slow to sensory input

Answer 1

slow

Question 2

are any hormones male or female specific

Answer 2

only placental hormones (lactose, chorionic gonadotropin)

only difference is the concentration of hormones

Question 3

hypothalamic pituitary testicular axis

Answer 3

stimulates testosterone production from the testes

1. hypothalamus: GnRH
2. ant. pituitary: LH, FSH
3. testes: testosterone

negative feedback of testosterone on GnRH

Question 4

hypothalamic pituitary gonadal uterine axis

Answer 4

1. hypothalamus: GnRH
   2a. ant. pituitary: LH, FSH
   2b. post. pituitary: oxytocin
   3a. ovaries: estrogen, progesterone
   3b. uterus: prostaglandins

• negative feedback of estrogen and progesterone on GnRH
• feedback of prostaglandins on ovaries to regulate cyclicity (livestock)
• reflexes from uterus stimulate oxytocin release from hypothalamus

Question 5

what repro hormones are produced in the hypothalamus

Answer 5

peptide hormones (GnRH, oxytocin)

Question 6

what repro hormones are produced in the anterior pituitary

Answer 6

glycoprotein gonadotropins (LH, FSH)
polypeptide proteins (prolactin)

Question 7

what repro hormones are produced in the gonads

Answer 7

steroid hormones (testosterone, estrogen, progesterone, estrone sulphate)
glycoproteins (AMH, inhibins)

Question 8

what repro hormones are produced in the uterus

Answer 8

prostaglandin F2a

Question 9

what repro hormones are produced in the placenta

Answer 9

steroid hormones (estrogen, progesterone, estrone sulphate)
glycoproteins (chronic gonadotropin)
placental lactogen

Question 10

what are the species specific hormones

Answer 10

1. glycoproteins (LH, FSH, chorionic gonadotropin, AMH, inhibins)
2. proteins (prolactin, placental lactogen, GH)

Question 11

characteristics of species specific hormones

Answer 11

• unique amino acid sequence across species
• requires species specific assays and drug modifications
• longer half life (esp. glycosylated)
• often have common A subunit and a unique B subunit

Question 12

what are the non-species specific hormones

Answer 12

1. peptides (GnRH, oxytocin)
2. steroids (testosterone, estrogen, progesterone)
3. prostaglandins (F2a, E2)

Question 13

characteristics of non-species specific hormones

Answer 13

• bioidentical sequences across species
• does NOT require species specific assays or drug modifications
• shorter half lives

Question 14

what are the types of clinical diagnostic assays for repro hormones

Answer 14

1. immunoassays
2. protein hormone assays
3. response tests

Question 15

immunoassays

Answer 15

antibody tests

single measures may not always be accurate due to fluctuations in hormone levels

requires species specific assays for species specific hormones

Question 16

protein hormone assays

Answer 16

species specific tests for protein hormones (prolactin, placental lactogen, GH)

Question 17

response tests

Answer 17

inducing the secretion of a specific hormone by administering a substance that stimulates its secretion, then running the assay for that hormone

ex. GnRH response test (admin GnRH to stimulate LH and testosterone, then measure the response of LH to GnRH & testosterone to LH)

Question 18

hormone receptor down regulation

Answer 18

chronic stimulation or administration of exogenous drug will down regulate the receptor and subsequent response

occurs in hormones that are normally secreted in a pulsatile manner (constant secretion results in reduced response)

ex. peptide hormones (GnRH, oxytocin)

Question 19

hormone receptor over-stimulation

Answer 19

prolonged exposure of hormone will over stimulate the target tissues to induce a hyper plastic/pathologic response

occurs in hormones with nuclear receptors (results in overactive response)

ex. steroid hormones

Question 20

what happens if a species specific hormone is administered to the incorrect species

Answer 20

increased risk of hypersensitivity reactions and antibody production