Flashcards in Male endocrinology Deck (35):
Explain the male HPA axis?
GnRH is released from the hypothalamus > LH & FSH release from the AP > act on the testes.
What cell does LH act on?
Leydig cells > release of testosterone.
What cell does FSH act on?
Sertoli cells > release of ABG & inhibin.
What is the function of ABG?
Keeps testosterone in the seminiferous tubules.
What is the function of inhibin?
Supports spermatogenesis & negative feedback.
What is male hypogonadism?
Dysfunctioning gonads > low serum testosterone.
What is primary hypogonadism?
Dysfunction within the gonads (i.e. failure of leydig cells).
What would primary hypogonadism show on blood investigations?
Elevated FSH & LH.
What causes primary hypogonadism?
Chronic liver & kidney disease.
Drugs & alcohol.
Radiotherapy & chemotherapy.
What is the treatment for primary hypogonadism?
Decanoate (synthetic testosterone).
PDE inhibitor - for erectile dysfunction.
What is secondary hypogonadism?
Low testosterone due to failure to secrete or insufficient GnRH.
What would secondary hypogonadism show on blood investigations?
Low FSH & LH.
What are the causes of secondary hypogonadism?
Hypopituitarism - low FSH & LH secretion.
What is the treatment for secondary hypogonadism?
HCG & FSH.
What is Kallmanns syndrome?
Genetic disorder > failure of GnRH neurones to migrate to the hypothalamus > absent/low GnRH release.
What is Klinefelters syndrome?
What are the symptoms of adult hypogonadism?
Small or absent testes.
Infertility & sexual dysfunction.
Reduced hair growth.
What are the symptoms of pubertal hypogonadism?
> lack secondary sexual characteristics.
> infantile genitalia.
What are the symptoms of foetal hypogonadism?
Development of a female.
What is male infertility?
Inability to fertilise a fertile woman.
What are the causes of male infertility?
Drugs & alcohol.
What are the signs of male infertility?
What is the treatment for male infertility?
Intracytoplasmic sperm injections.
GnRH therapy - if infertility is due to secondary hypogonadism.
What is androgen insensitivity syndrome?
X-linked autosomal recessive disorder.
What are the main causes of AIS?
Mutations in the androgen receptor.
Mutations in the 5a reductase gene.
What does 5a reductase do?
Converts testosterone in DHT which is required for masculinsation of the foetus.
What are the signs of AIS?
Males born with ambigious genitalia:
> blind ended vaginas.
> small clitoris.
> small testes present.
> Bilateral inguinal hernias.
What is the treatment for AIS?
Oestrogen replacement therapy.
What is precocious puberty?
Puberty occurring at an unusually early age:
> puberty before 7-8 years in females.
> puberty before 9-10 years in males.
What are the types of precocious puberty?
> Gonadotropin dependant (i.e. increased release of gonadotropins from the HPG axis).
> Gonadotropin independent (not due to increased release of gonadotropins from the HPG axis).
What are the causes of central precocious puberty?
Hypothalamic hamartoma - benign tumour that produces GnRH.
Pineal gland tumour.
What are the causes of precocious pseudopuberty?
Congenital adrenal hyperplasia.
Adrenal or gonadal tumours.
HCG secreting tumours - HCG is a analog of LH.
What are the signs of precocious puberty?
What is the treatment for central precocious puberty?