Leydig cells are _______ the membrane, and Sertoli cells are _____ the membrane
Outside the membrane (Leydig are interstitial cells)
Sertoli are found within the seminiferous tubules
Which cell produces testosterone?
Leydig
What does Sertoli cell do?
Provides protein needed for sperm
T/F: other than LH which stimulates the conversion of cholesterol to pregnenolone, ACTH can do the same thing
True
What is the enzyme that converts testosterone to dihydrotestosterone in target tissues?
5 alpha reductase
Testosterone will turn into ______ with aromatase; testosterone will turn into ______ with 5 alpha reductase
Estradiol
Dihydrotestosterone (DHT)
T/F a small amounts of testosterone and estradiol are produced by the zona reticularis of the adrenal glad
True; most of the synthesis of these are made in testes and ovaries
Most of the adrenal gland synthesized androgen are _____ and ____. Conversion to testosterone and estradiol occurs _______
DHEA
Androstenedione
In peripheral tissues
T/F: Like in the ovaries, testes can convert androstenedione to aldosterone and glucocorticoids
False; testes only have 17 beta hydroxysteroid, they do not have 21 hydroxylase and 11 beta hydroxylase, so production of glucocorticoids or mineralocorticoids is not possible
In males, LH stimulates _______ cells and FSH stimulates ______ cells
Leydig – make testosterone
Sertoli
GnRH is secreted by _____ nuclei in the hypothalamus
Arcuate and preoptic
Factors that can inhibit release of GnRH:
Melatonin
CRH
Dopamine
Endorophin
Prolactin
Factors that can stimulate GnRH:
Norepinephrine
Pheromones
T/F: LH and FSH are much like TSH in terms of structure
True , same alpha subunit, different beta subunit
T/F: unlike ovary, LH receptor could only be found in the Leydig cell, as opposed to in both Leydig and Sertoli, like how LH receptor is found in both granulosa and theca cells
True
Which hormone stimulates spermatogenesis?
FSH (which also stimulates the Sertoli cell)
What is required of the testosterone concentration for spermatogenesis to occur?
High intratesticular concentration
T/F: infertile males who lack GnRH can be treated with programmed pulses of GnRH
True
Long-acting GnRH would have what effect to testosterone and estrogen, and therefore what effect on puberty?
Would suppress testosterone and estrogen, because it desensitize GnRH receptor in the pituitary, therefore puberty would not occur
In Childhood, LH level is ____ than FSH, in adult reproductive period, LH level is ______ than FSH, and when youre really old, your LH level is ____ than FSH
Greater
Greater (and pulsatile)
Less
Testicles get big under the stimulation of _____, and testosterone secretion is under stimulation of _____
FSH
LH
_____ leads to somatic growth and skeletal development. The prorductive organs mature
Testosterone
Testosterone inhibits the hypothalamus and anterior pituitary secretion of _____, and at high doses of testosterone, it would also inhibit _____
LH primarily
FSH at high doses
Inhibin is produced by _____ cells, and its release is stimulated by _____.
Sertoli
FSH
T/F: Activin from gonads can provide positive feedback to the anterior pituitary for FSH release
True
Where can androgen receptors that initiate gene transcription be found?
Inside the cell
T/F: Dihydrotestosterone (DHT) binds less effectively than testosterone receptor
False; DHT binds the testosterone receptor more effectively
T/F: like estrogen, testosterone makes your skin soft and smooth
False; it thickens your skin and causes acne
Differentiation of penis, scrotum, and prostate is mediated by _____
DHT
Male pattern hair loss is mediated by ____
DHT
Increased muscle mass and pubertal growth spurt is mediated by ____
Testosterone
Growth of penis and seminal vesicles, deepening of voice is mediated by ____
Testosterone
____ drives the basal rate of spermatogenesis
Testosterone
How does Sertoli cell support spermatogenesis?
Sertoli cells produce more than 100 proteins in response to FSH and these proteins support spermatogenesis
T/F: testosterone secretion is temperature sensitive, needs to be lower than body temperature
False; spermatogenesis requires a temperature lower than body temperature, not testosterone secretion
A lot of athletes have _____Second finger than their fourth
Second
T/F: testosterone triggers aggression
False; no prove that it triggers aggression directly, but testosterone could relieve inhibition of aggression.
Athletes who abuse steroids would have ____ and ______, and some would thus take ____ to counteract it. But would then have to take _____ this counteract the symptom caused by the former
