Endocrine Regulation of Male Fertility Flashcards
What are the cells of the male reproductive system and what do they do? [3]
- spermatocytes
- develop into sperm
- Leydig cells
- secrete testosterone to promote sperm development
- Sertoli cells
- blood-testis barrier
- remove damaged spermatocytes
- secrete androgen binding protein
What are the 2 molecules that most circulating testosterone is bound to? [2]
- sex-hormone binding globulin (SHBG)
- albumin
List the effects of testosterone on the body under the following headings:
- growth [5]
- adults [5]
- fertility [3]
- other effects [2]
- Growth
- Sex organs
- Skeletal muscle
- Epiphyseal plates
- Larynx growth
- Secondary characteristics
- Adult
- Muscle mass
- Mood
- Bone mass
- Libido
- Body shape
- Fertility
- Libido
- Erectile function
- Spermatogenesis
- Other effects
- Erythropoiesis
- Behaviour
How is male gonadal function controlled? [8]
What are the clinical features of hypogonadism in children/young adults? [4]
- Slow growth in teens
- No puberty growth spurt
- Small testes & phallus
- Lack of secondary sexual development
What are the clinical features of hypogonadism in adults? [11]
- Depression/low mood
- Poor libido
- Erectile problems
- Poor muscle bulk/power
- Poor energy
- Sparse body/facial hair
- Gynaecomastia
- Gynoid weight gain
- Great head hair
- Short phallus
- Small testes - abnormal consistency
What are the tests used to investigate hypogonadism? [5]
- Sex steroid deficiency
- Testosterone
- LH & FSH
- Fertility
- Semen analysis
When is a semen analysis usually done and what are the normal figures? [5]
- 1-3 days after last ejaculation
- 2-5ml volume
- 20 x 106 sperm/ml
- 50% progressive motility
- ≥30% normal morphology
What are the general biochemical abnormalities associated with hypogonadotrophic hypogonadism? [7]
- Low testosterone
- Low LH +/- FSH
- +/- Increased prolactin
- +/- Decreased cortisol
- +/- Decreased IGF-1/GH
- +/- Decreased TSH
- +/- Increased Na+
What are the causes of hypopituitarism? [6]
- Pituitary tumour
- Pituitary surgery/radiotherapy
- Head injury
- Kallmann’s syndrome
- Isolated LH & FSH deficiency
- Cerebellar ataxia
- Genetic syndromes
Describe the pathogenesis of Kallmann’s Syndrome and what conditions is it associated with? [4]
- Failure of cell migration of GnRH cells to hypothalamus from olfactory placode
- Associated with aplasia/hypoplasia of olfactory lobes — giving anosmia or hyposmia
- Also may be associated with deafness, renal agenesis, cleft lip/palate
- May have micropenis ± cryptorchidism
Describe the genetic basis of Kallmann’s Syndrome [5]
- Familial with variable penetration
- X-linked - absence of KAL gene (KAL1)
- Autosomal dominant (KAL2)
- Autosomal recessive (KAL3)
- Other genetic causes of IHH exist (e.g. Kisspeptin/GPR54 mutations)
What are the signs and symptoms of Kallmann’s Syndrome in…
- childhood? [2]
- adolescence? [4]
- adults? [4]
- Signs & Symptoms in Childhood:
- Poor growth
- Undescended testes
- Signs & Symptoms in Adolescence:
- Poor growth
- Small testes
- Micropenis
- Delayed/absent puberty features
- Signs & Symptoms in Adults:
- Slow, but adequate growth
- Small testes
- Small phallus
- Hypogonadal features
What are the causes of primary gonadal failure? [5]
- Klinefelter’s syndrome
- Due to chromosome defects
- Complex genetic syndromes
- Cryptorchidism
- Adult Leydig Cell Failure & Seminiferous Tubule Failure
- Can be caused by:
- Trauma
- Chemotherapy
- Radiotherapy
- Multisystem disorders
- Can be caused by:
Describe the clinical pathogenesis of Klinefelter’s Syndrome [4]
- XXY (but other sex chromosome variations exist)
- Clinically manifests at puberty
- Increased ↑LH & FSH
- but seminiferous tubules regress & Leydig cells don’t function normally
The clinical presentation of Klinefelter’s Syndrome is widely variable. What are the typical presenting features? [6]
- Delayed puberty
- Suboptimal genital development
- Reduced secondary male sexual characteristics
- Persistent gynaecomastia
- Azoospermia
- Behavioural issues/learning difficulties
What are the management options for Klinefelter’s syndrome? [3]
- Androgen replacement +/-
- Psychological support +/-
- Fertility counselling
What are the treatment options for hypogonadism? [5]
- Androgen replacement therapy
- can be administered orally, IM or topical
- Fertility treatment
- hCG
- Recombinant LH & FSH
- GnRH pumps
What are the side effects of androgen replacement treatment? [6]
- Mood issues (aggression/behaviour change)
- Libido issues
- Increased haematocrit
- Possible prostate effects
- Acne, sweating
- Gynecomastia
