Richter- Male Reproductive Function Flashcards
nurse cell that surrounds germ cells
sertoli cells
interstitial cell that makes testosterone
Leydig cell
low testosterone, reduced fertility/infertility (still genetically a male) XXY
Klinefelter syndrome
gonads are indifferent up to _____ weeks of gestation
5
Gene products of the _____ locus drive the development of male gonads
SRY (sex-determiningregion of theYchromosome)
_____ cells begin to secrete Anti-Mullerian Hormone (AMH) leading to regression of the Mullerian duct (the precursor of female reproductive structures)
Sertoli cells
______ weeks, Leydig cells begin to secrete testosterone (+ feedback for wolffian ducts to allow male reproductive structures to develop)
8-9 weeks
______ turned into DHT promotes growth of Wolffian ducts into male reproductive structures
testosterone
after 9 weeks, ____ chromosome is activated and initiates oogenesis
X chromosome
In absence of AMH, ______ ducts develop into female reproductive structures (no hormone required)
Mullerian
_____ ducts regress at 10 weeks due to lack of testosterone
Wolffian ducts
_____ ducts need testosterone to develop
Wolffian
___ chromosome determines sex
Y
primordial germ cells in males
spermatogonia
surround germ cells and make AMH in males
sertoli cells
surround germ cells and do not make AMH in female
granulosa cells
make testosterone in males (androgens)
Leydig cell
make estrogen in females (no androgens)
Theca cell
creates blood-testis barrier
required for sperm growth and maturation
FSH maintains this cell function
Sertoli cell
responsible for testosterone synthesis
Leydig cells
____ stimulates testosterone production
LH
Leydig cells have high expression levels of _____, one of the rate-limiting enzymes in testosterone synthesis
17-beta-HSD
steroid hormone synthesized from cholesterol
testosterone
cholesterol of side-chain cleavage enzyme located where
inner mitochondrial membrane
enzyme used for the 3 steps going down before testosterone is made
3-beta-HSD
enzyme used for estrogen production
aromatase
outside of Leydig cell, ____ binds to androgen binding protein synthesized by sertoli cells
testosterone
what allows for high accumulation of testosterone in testis
testosterone binding to ABP from sertoli cells
how is testosterone transported throughout body
blood bound
how does testosterone act on target cells
binding to androgen receptor which is a nuclear receptor that regulates gene expression
testosterone can be converted in target tissues to ______
dihydrotestosterone (DHT)
testosterone into DHT by what enzyme
5-alpha reductase
testosterone into estradiol by what enzyme
aromatase
FSH and LH are released from ____ pituitary
anterior
characteristics of LH receptor on Leydig cells
Gs (increasing cAMP production to stimulate testosterone synthesis)
______ signaling induces StAR
cAMP/PKA
_____ promotes transport of cholesterol to the side-chain-cleavage enzyme located in the inner mitochondrial membrane
StAR
characteristics of FSH receptor on sertoli cells
Gs which increases cAMP
_____ stimulates the expression of aromatase, ABP (androgen binding protein) and growth factors necessary for spermatogenesis and Sertoli cell function.
FSH binding
_____ moves through the basal lamina into sertoli cells
testosterone
2 fates of testosterone once it goes into sertoli cells:
- exit into seminiferous tubule lumen and binds ABP and regulates spermatogenesis
- testosterone can be converted to estradiol 17 beta by aromatase
Pulsatile release of _____ from hypothalamic neurons promotes LH and FSH expression and release in the anterior pituitary
GnRH
characteristics of GnRH receptor
Gq/PLC (Ca2+)
activator of PKC
DAG
what promotes synthesis of FSH and LH
PKC
____ produces IP3 and releases Ca2+
PLC
signals vesicles to fuse with cell membrane and release LH and FSH
Ca2+
if sertoli cells receive enough of FSH, what is released
inhibin
suppresses anterior pituitary from expressing/secreting FSH
inhibin
circulating testosterone blocks _____ release from hypothalamus as well as LH expression in pituitary
GnRH
Because the Sertoli cells produce ________ the testis can have high local testosterone without contributing to the NEGATIVE FEEDBACK LOOP.
ABP (androgen binding protein)
The effect of _____ on LH expression is mediated primarily upon its conversion to estradiol by the action of aromatase.
testosterone
binding ____ to ABP keeps testosterone in blood low and more FSH and LH signaling
testosterone
peripheral testosterone suppresses LH and GnRH and FSH; suppress endogenous production of testosterone from Leydig cells; suppress Sertoli cells; suppress spermatogenesis
shrivel the balls and suppress fertility
testosterone injections
both testosterone and ____ bind same androgen receptor
DHT
Growth and development of male genitalia and reproductive structures (vas deferens, epididymis, glands, etc.)
Sperm production
Libido
testosterone and DHT
Growth of penis and scrotum
Growth of facial hair
Increase prostate growth (prostate hyperplasia)
Male pattern baldness
DHT only
In utero development of male reproductive tract
Increases muscle mass at puberty
Regulates liver lipoprotein profiles
Promotes male fat distribution
Thickens vocal chords
testosterone only
testosterone can be converted to ______ in periphery (adipose tissue, bone, brain) by aromatase
estradiol
GnRH secretion is low; testes are quiescent; androgen levels low
ages?
1-10
pulsatile GnRH secretion begins; LH and FSH are released in higher concentrations
age?
10-12
puberty begins; testosterone levels rise and secondary sex characteristics begin to develop
age?
12-14
testosterone levels reach maximum
age?
18-20
reduction in fertility in males after age 40
andropause
low or high pH and low or high temp does what to sperm motility
low pH and high temp