Reproductive Endocrinology I Flashcards
(33 cards)
What are the 3 ways to classify sexually reproducing animals?
(1) Division if individuals according to egg/sperm production.(2) Method of production.(3) Method of fertilization.
Define gonochoristic species. What is this related to?
Separation of gonads into separate-sexed individuals. (Genoypic GSP and environmental ESD).*Related to division of individuals according to egg / sperm production.
Define hermaphroditic species. What is this related to?
Individual has both types of gonads, but cannot self-fertilize.*Related to division of individuals according to egg / sperm production.
Define sequential hermaphrodites. What is this related to?
They undergo sex change. Protogynous ~> female to male, Protandrous ~> male to female.*Related to division of individuals according to egg / sperm production.
Name two examples of sequential hermaphrodites.
(1) Common Reed Frog (hyperolius viridiflavus). Used to DNA seq. / guess about dinosaurs(2) Bluehead Wrasse, 2-6 weeks to sex change. Instigated by an increase in AVT; if there are also behavior changes in harem aka too many females?
Define oviparity and viviparity.
Oviparity = egg layersVivaparity = live bearing*both mammals, fish, and amphibians are examples of these. Birds cannot be vivaparitous.
What is ovoviviparous / ovoviviparity?
When eggs are retained within and hatch in an adult. (Seahorse, sharks, invertebrates, etc.)
What are the two methods of fertilization?
(1) External; amphibians, fishes.(2) Internal; mammals, birds, reptiles, some amphibians / fishes.
Name some environmental cues for the timing of reproductive cycles. (4)
1) Photoperiod (on/off; mammals, birds, reptiles)2) Temperature (amphibians and reptiles)3) Moisture (amphibians and reptiles)4) Lunar cycles (fish) *These establish ‘tides’
Name some examples of ‘photoperiod’ in action.
(1) Long days ~> gonadal recurdescence in European Starlings(2) Endogenous circannual rhythm is entrained [schedulized] by photoperiod in sheep, but ransition to ‘anestrus’ (gonald regression) depends on thyroid hormone.
Names the reproductive hormones in:1) hypothalamus2) pituitary3) gonads
1) GnRH (aka LHRH, LRF; luteinizing releasing factor), GnIH [2007], Kisspeptin ~> + regulator [2007/2008]2) LH, FSH (PRL which suppresses LH and FSH)3) Sex steroid (androgens, estrogens, progestins); gonadal peptides like: inhibin, activin, follistatin
Progestins (C21 steroids), which one is the precursor of all steroid hormones?*Name a receptor blocker.
Progesterone. RU486 (mifepristone) is a Progesterone receptor [essentail for pregnancy] blocker / glucocorticoid antagonist.
1) Name some androgens (C19 steroids).2) Name some androgen receptor blockers.
1) Testosterone (T), 5α-dihydrotestosterone (DHT), androstenedione, dehydroepiandrosterone (DHEA, DHEA-S)2) Cyproterone acetate, Spironolactone (also blocks MR), *5α reductase inhibitors: [Finasteride, Dutaserid, saw palmetto extract] lead to benign prostaphasia.
Where and how is DHT synthesize?
Synthesized from T in target tissues by 5α reductase enzyme.
1) Name some Estrogens (C18 steroids).2) Name an E2 blocker.3) Name an aromatase inhibitor
1) 17β estradiol (most important one); generated from androgens (T, androstenedione, DHEA) by aromatization (aromatase).2) Tamoxifen3) Fadrazole
What do Inhibins do?
Inhibit FSH production by pituitary. Block oocyte maturation, follicular development.
What do Activins do?
Stimulate FSH production.
What does Follistatin do?
It’s an activin binding protein. It inhibits FSH release by binding activin.
Where were activins and inhibins first discovered? What family members are they a part of?
In pigs. They are members of the TGFbeta superfamily.
The Mullerian Duct…
Gives rise to female urogenital tract.
The Wolffian Duct…
Give rise to male urogenital tract.
What does it mean that female is the ‘default sex’?
The mullerian duct will develop if there is no androgen. Androgen stimulates produciton of anti-mullerian hormone (AMH; or Mullerian Inhibitin gSubstance MIS).~> Wolffian duct development.
What is Temperature Dependent Sex Determination (TSD)?
Temperature determines offspring sex in species. An ESD (environmental sex determination).
Describe puberty in females (estrogen, progesterone).
Breast development, enlargement of labia minora an dmajora (estrogens), pubic hair growth (androgens from adrenal and ovary). Uterus and ovaries enlarge.
