Wk3 Male Repro Phys Flashcards
Duration of a full cycle of spermatogenesis; “spermatogenic wave”:
64 days
Inhibin inhibits?
anterior pituitary
FSH and LH
Testosterone inhibits:
Hypothalamus AND Anterior pituitary
FSH/LH and GnRH
LH acts on _______ cells.
Leydig
FSH acts on _______ cells.
Sertoli
Inhibin comes from _________ cells.
Sertoli
Numerical relationship between sperm production and Sertoli cell number:
linear
Numerical relationship between sperm production and Leydig cell number:
Why?
Linear
Testosterone helps stimulate Sertoli cells
What would decreased testosterone levels do to GrRH?
increase
**less negative feedback
Physical musculoskeletal effects of low testosterone:
increased abdominal fat
decreased muscle mass
Finasteride
5-a-reductase inhibitor
Tx for: baldness, prostate CA
What does 5-a-reductase do?
converts testosterone to DHT (more potent form)
Testosterone targets:
Muscle
Seminal Vesicle
Epidydimis
Bone
8 mg of daily testosterone in males produced in which two places?
Leydig cells (Testes) — 95%
adrenals — 5%
Androgen receptor location and site of action:
cytoplasm — binding of androgens
nuclear transcription factors
Anabolic effects of androgens (3):
- muscle building
- bone growth – closure of epiphysis
- Na/H2O retention
Read slide….
20
Testosterone analog
hormone replacement
hepatotoxic
Methyl testosterone
DHT derivative
anabolic steroid
Oxandrolone
What happens to gonads with exogenous testosterone use:
shrink
**inhibits hypothalamic pituitary axis –> no stimulation of androgen receptors
Read slide…
28
Non-steroidal
Pure steroid receptor antagonists
Flutamide
Bicalutamide
Difference between “pulsatile” and “continuous” exposure to GnRH analogs:
“pulsatile” is stimulatory
“continuous” is inhibitory
GnRH analog (recombinant human form)
pulsatile for 3-6 mo for male infertility
Gonadorelin