Endocrine Regulation of Male Infertility Flashcards
(27 cards)
Which cells produce testosterone?
Leydig cells
Testosterone in the blood circulates bound to which proteins?
Sex hormone binding globulin (SHBG)
Albumin
What are the effects of testosterone in the body?
Growth of the sex organs, skeletal muscle, epiphyseal plates, larynx, secondary sex characteristics Erythropoiesis Behavioural changes Libido Erectile function Spermatogenesis
How does hypogonadism affect a child or young adult?
Slow growth in teens
No pubertal growth spurt
What can be used to measure the size of the testes?
Orchidometer
When should testosterone levels by tested for in suspected hypogonadism?
Early morning testosterone
Why is it useful to know the LH and FSH levels in suspected hypogonadism?
Helps to determine if there is a possible pituitary cause
What is the term for hypogonadism caused by a pituitary problem?
Hypogonadotrophic hypogonadism
In hypogonadotrophic hypogonadism there is a low testosterone and low LH/FSH. What other hormones might be affected?
Increased prolactin Decreased cortisol Decreased IGF-1/GH Decreased TSH Increased sodium
What are the possible causes of hypogonadotrophic hypogonadism?
Pituitary tumours Pituitary surgery/radiotherapy Genetic syndromes Cerebellar ataxia Kallmann's syndrome Head injury
What is the most common cause of isolated gonadotrophin deficiency?
Kallmann’s syndrome
What is Kallmann’s syndrome?
A failure of cell migration of GnRH cells to the hypothalamus from the olfactory placode.
Kallmann’s syndrome is associated with aplasia/hypoplasia or the olfactory lobes. What is the result of this?
Anosmia or hyposmia
As well as hypogonadism, what is Kallmann’s syndrome associated with?
Aplasia/hypoplasia of the olfactory lobes leading to anosmia/hyposmia Deafness Renal agenesis Cleft lip/palate Micropenis +/- cryptorchidism
Kallmann’s syndrome is familial. What are the three possible modes of inheritance in this syndrome?
X-linked due to absence of KAL gene (KAL1) Autosomal dominant (KAL2) Autosomal recessive (KAL3)
Other than Kallman’s syndrome what are the possible causes of inherited hypogonadotrophic hypogaondism?
Kisspeptin mutations
GPR54 mutations
What are the clinical features of Kallmann’s in childhood, adolescence and adults?
Childhood - poor growth and undescended testes
Adolesence - poor growth, small testes, micropenis, delayed/absent puberty
Adults - slow, but adequate growth, small testes, small phallus, hypogonadal features
What are the biochemical features of primary gonadal failure?
Low testosterone
Normal/high LH and FSH
Normal prolactin
What are the possible causes of seminiferous tubule failure and adult leydig cell failure?
Trauma
Chemotherapy
Radiotherapy
Multi-system disorders
What is the most common cause of male hypogonadism?
Klinefelter’s syndrome
What chromosomal abnormality is seen in Klinefelter’s syndrome?
47XXY
At what stage of development does Klinefelter’s syndrome manifest clinically?
Puberty
What are the clinical features of Klinefelter’s syndrome?
Delayed puberty Suboptimal genital development Reduced secondary male sexual characteristics Persistent gynaecomastia Azoospermia Behavioural issues Learning difficulties
How is Klinefelter’s syndrome treated?
Androgen replacement possibly alongside psychological support and fertility counselling
