Male reproductive endocrinology

Question 1

what are the requirements for normal function

Answer 1

gonadal and reproductive system development
intact reproductive hormone production
puberty
spermatogenesis
normal spermatozoa
erectile function
non-obstructive anatomy

Question 2

what are hormones key for

Answer 2

during development of the testicular reproductive system
during puberty and spermatogenesis
during sperm production and erectile function

Question 3

what key changes occur in foetal life

Answer 3

process of sex determination (XY karyotype)
formation of testis (largely independent of hormones)
testosterone is important once testis have formed for activity within them and for masculinisation of the foetus

Question 4

what controls the development of the male reproductive system

Answer 4

under control of the hypothalamic-pituitary-gonadal (HPG) axis
active during foetal development and lasts until around birth

Question 5

what is the function of anti-mullerian hormone

Answer 5

induces regression of mullerian ducts (oviducts, uterus, vagina)
produced by testicular sertoli cells

Question 6

what is the function of testosterone in foetal life

Answer 6

maintains the male reproductive structures

Question 7

what occurs during infancy

Answer 7

HPG axis is reactivated (lasts ~3-6months)
called ‘mini-puberty’

Question 8

what is ‘mini-puberty’ important for

Answer 8

development of external genitalia
window for investigating reproductive function

Question 9

what occurs during childhood

Answer 9

HPG axis is inactive
no testosterone
no sperm
prepubertal testis do have germ stem cells (sperm), sertoli cells (fertility) and leydig cells (puberty and testosterone)

Question 10

what occurs during puberty

Answer 10

HPG axis is activated
responsible for initiation of spermatogenesis and secondary sex characteristics
normally occurs around 9-14

Question 11

what is pubertal staging

Answer 11

assessment of pubertal development
focuses on development of axillary and pubic hair, development of external genitalia and testicular volumes

Question 12

when is the GnRH stimulation test used

Answer 12

when there are concerns about puberty or delay in testicular function

Question 13

what occurs throughout adulthood

Answer 13

maintenance of secondary sex characteristics and of testosterone production
continuous spermatogenesis and sperm production is the goal
HPG axis is super important for this

Question 14

what are environmental disorders

Answer 14

cryptorchidism (undescended testes)
hypospadias (abnormality of the urethral opening)
infertility
testicular cancer
hypogonadism
collectively known as testicular dysgenesis syndrome

Question 15

what are genetic disorders

Answer 15

ambiguous genitalia
gonadal tumours
hypogonadism
infertility
collectively referred to as disorders of sex development

Question 16

what is a karyotype used for

Answer 16

determine if the patient is an undervirilised XY or a virilised XX, or any other type

Question 17

what is an ultrasound/MRI used for

Answer 17

determine what the ambiguous structures are
location (if gonads in inguinal/scrotum region indicates testes, if in abdomen indicated ovaries)
determine what hormones are being produced from the structures
if uterus is absent, indicates testes
can do a laparoscopic surgery for further investigation

Question 18

what is the function of testosterone

Answer 18

testosterone activates androgen receptors leading to gonadal descent
5alpha-reductase converts testosterone to dihydrotestosterone (DHT) which leads to development of external genitalia

Question 19

what can abnormalities of hormone pathways lead to

Answer 19

all types of disorders, particularly cryptorchidism and ambiguous genitalia

Question 20

how is genetics tested

Answer 20

sequence the androgen receptor gene on the X-chromosome,
if mutation is identified in the AR diagnosis is (partial) androgen insensitivity syndrome (PAIS)

Question 21

what are the stages of puberty

Answer 21

stage 1 is completely pre-pubertal
stage 5 is normal adult male development

Question 22

what are some final diagnostic tests

Answer 22

GnRH stimulation test, also production of LH, FSH and testosterone
scrotal ultrasound - testicular masses, epididymal cysts, varicocele
tumour markers - hCG, AFP, LDH

Question 23

what can cancer treatment as a boy cause

Answer 23

chemo and radiotherapy can lead to delayed puberty and eventual hypogonadism
can also cause infertility

Question 24

what can be done for cancer

Answer 24

surgery - orchidectomy (removal of a testis)
pathology - seminoma vs non-seminoma
staging of cancer

Question 25

where does the risk of infertility come from in cancer treatment

Answer 25

TDS or treatment
can do sperm banking before treatment

Question 26

what is hypogonadotropic hypogonadism

Answer 26

decreased LH, FSH and testosterone
something in brain has been affected

Question 27

what are the diagnoses for hypogonadotropic hypogonadism

Answer 27

delayed puberty
congenital hypog hypog
brain tumour
radiotherapy
kallmann’s syndrome (if they cant smell)

Question 28

what is the treatment for hypog hypog

Answer 28

testosterone and gonadotrophins to induce puberty and fertility

Question 29

what is hypergonadotrophic hypogonadism

Answer 29

increased LH and FSH but decreased testosterone

Question 30

what are the diagnoses for hyper hypog

Answer 30

Klinefelter syndrome
DSD/gonadal dysgenesis
chemo/radiotherapy