1.3.3 Male Reproductive Endocrinology Flashcards
(39 cards)
Name three factors that stimulate GnRH release
Leptin, norepinephrine (NE), neuropeptide Y (NPY)
Where is the majority of estradiol produced? How?
Adipose; aromatization of testosterone
What does inhibin level correlate with?
total sperm count and testicular volume
index of spermatogenesis
What is the main function of inhibin B from sertoli cells?
Suppress FSH secretion from pituitary
ABP produced and released?
Produced by sertoli cells and released into the lumen of the seminiferous tubules
What are the three principal hormones produced by the gonads?
Testosterone and Estradiol (Leydig cells)
Inhibin B (Sertoli)
What is andropaus
Along with secondary sex characteristic development, what occurs during puberty?
Growth
What do sertoli cells release in the negative feedback loop on FSH?
Inhibin B
What factors inhibit the release of GnRH? (5)
GABA, dopamine (DA), IL-1, beta-endorphin, prolactin
How does gonadotrophins (LH and FSH) work?
Bind G protein receptors, activate AC, production of cAMP, activation of protein kinase A (PKA)
What does testosterone control?
What is activin?
locally (pituitary) produced peptide that antagonizes inhibin B resulting in the stimulation of FSH release
What are the key steps in testerone synthesis and metabolism?
Draw out the pituitary axis of LH/FSH with the reproductive system
Shortly after birth, what happens to newborn baby boys?
Huge stimulation of LH leading to high levels of testosterone
What receptors are present on sertoli cells? (2)
FSH and androgen receptors
How does testerone act?
Passively diffuses through cells
Inactivate cytosolic androgen receptor
Ultimately, activate gene txn
What type of cells responds to LH?
Leydig cells
What are some of the characteristics of someone with Klinefelter’s syndrome?
What could cause precocious puberty?
What does degradation occur?
Liver
What protein plays a key role in the first step of steriod hormone biosynthesis?
Steriodogenic acute regulatory (StAR) protein
