LC 3.7 Male Sexual Function and Ageing Flashcards
What are the two functions of the testis? What cells does each involve?
- Produce sperm (leydig cells)
* Produce hormones (sertoli cells)
Outline the hormones in the sex steroid axis
GnRH
LH
Testosterone
Why does anabolic steroid use lead to infertility?
Negative feedback caused by steroid use suppresses endogenous testosterone production. High concentrations needed in the seminiferous tubules for sperm to develop properly.
What is free testosterone responsible for regulating?
- Haematopoesis
- Muscle development
- Fat redistribution
- Hair growth
How do testosterone levels change over a lifetime?
Peaks in early twenties, then slowly declines (andropause)
What causes the decreased production of testosterone with age? (andropause)
- Apoptosis of Leydig cells
- Lack of response to LH
- Obesity
Why does obesity reduce testosterone levels?
Fat produces oestrogen, which negatively feeds back to the sex steroid axis, inhibiting it.
What are the effects of andropause
- Decreased sexual function
- Mood changes and Fatigue
- Decreased muscle and Increased fat
- Decreased bone mineral density
- Decreased haemoglobin
What are the potential benefits of HRT for men?
Decreases fat and increases muscle, which helps mobility.
What are the cons of HRT for men?
- Exercise programmes have the same effect on mobility
* There is a risk of prostate cancer and CVS impact
In what ways is male fertility affected by ageing?
- There is a reduced Sertoli cell function and so reduced sperm quality
- Increased developmental problem risk
- Inconsistent effects on fertility; can be preserved but there is a decline
What changes occur to the prostate with age?
- Reduced secretion of seminal plasma
* Prostatic neoplasia occurs
What types of prostatic neoplasia occur, and what is the prevalence of each in 70 year old men?
- Benign prostatic hyperplasia - 70%
* Prostate cancer - 3%
What does reduced secretion of seminal plasma with age cause?
- Reduced ejaculate volume
- Thicker semen
- Reduced force of ejaculation
What changes in sexual function occur with age?
- Decreased libido
- Prolonged arousal and decreased sensitivity
- Reduced erectile rigidity
- Decreased intensity of orgasm
- Increased refractory period
What are the causes of erectile dysfunction?
Failure of cavernosal smooth muscle relaxation:
• Loss of desire
• Nerve damage
• Failure of smooth muscle to relax (fibrosis?)
• Blocked or narrowed arteries
How does an erection occur?
- Stimulus occurs
- NO released
- cGMP formed
- Vascular smooth muscle relaxes
- Sinusoids of corpora cavernosa swell with blood
- Swollen sinusoids impinge upon emissary veins, trapping blood inside
- Smooth muscle in sinusoids relaxes
What are the risk factors of erectile dysfunction?
- Age
- Diabetes and hyperlipidaemia
- Depression
- Peripheral vascular disease
- IHD
- Hypertension
What can cause smooth muscle dysfunction?
- Toxins
* Diabetes
What is indicative of erectile dysfunction being of a psychological cause?
- Sudden onset
- Relationship issue
- Morning wood present
- Young patient
- Intermittent problem
How is erectile dysfunction diagnosed?
Check for risk factors • Check BP • Check size of testes (small =hypogonadism) • Check blood sugar for diabetes • Check lipid profile • Check testosterone level
When must testosterone levels be checked and why?
In the morning due to diurnal variation
What is the treatment for ED?
- Change lifestyle/situation to reduce stress, lose weight, stop smoking, etc.
- Drugs to combat underlying causes (e.g. ACE inhibitors for hypertension or antidepressants)
- Psychosexual therapy
- Direct pharmacological
What pharmacological options are available for the treatment of ED?
Centrally acting (uncommon) • Apomorphine (dopamine antagonist)
Smooth muscle relaxants: phosphodiesterase 5 inhibitors (PDE5Is)
• Sildenafil (Viagra)
• Tadalafil (Cialis)
• Vardenafil (Levitra)
Intra-cavernosal injections
• Prostaglandin E1
