Hormonal control of ageing Flashcards
What 2 major interventions have a whole systemic effect on ageing?
Insulin interventions and calorie deficit.
What happens to ageing when you remove the pituitary gland?
Helps maintain collagen integrity in animals, didn’t make them live longer but seems they lived healthier.
What happens when you remove the pituitary gland and supplement an animal with stress hormones?
The animal lives longer.
What is the relationship between ageing and hormones?
Ageing is typically associated with a decline in hormone level.
What happens to the levels of growth hormone with age?
Decrease drastically after 50.
Can growth hormones reverse ageing?
In the study done in humans muscle performance improved but no evidence for overall ageing but successful in dwarf mice.
What is Laron syndrome?
Mutant GH receptor resulting in high GH and very low IGF-1.
What are the advantages with laron syndrome?
Don’t live longer but have lower levels of cancer and low diabetes.
What is the effect of reducing IGF on ageing?
Reduces it.
What happen when you reduce IFG too far?
Diabetes
What mechanisms are involved with growth hormone signalling?
Inflammation
Growth
Defence
Metabolic adjustments.
What happens with woman’s hormones during menopause?
FSH up
LH up
Estradiol low
Inhibin low
Progesterone low.
Ovulation is no longer possible.
Why does ovulation no longer occur during menopause?
Because the negative feedback loop is no longer possible.
What happens during perimenopause (approaching full menopause)?
FSH up
LH surge low and more erratic
Inhibin low.
Results in shortened follicular phase.
More twins
Why does the body produce twins during perimenopause?
This is because the body releases more eggs, the body’s last push in reproduction.
What is the function of Calorie Restriction?
Calorie Restriction preserves ovaries and on refeeding can reproduce at late ages.
What happened in mice when they gave an old mouse, young mouse ovaries?
Extended life span and healthier profile.
What is the advantage of oestrogen for life span?
Upregulates antioxidants, less ROS.
What happens in the body when you reduce FSH?
Increases bone mass, and increases survival and mobility.
How is reducing LH beneficial?
Improves cognitive function, reduces chances of dementia.
What happens to testosterone with ageing?
Declines with age.
What would the advantage restoration of testosterone be for ageing?
Sexual function, bone and muscle strength.
What would the disadvantage of restoration of testosterone be for ageing?
Increases risk of prostate cancer
What is the idea of the reproductive/survival trade off?
Women who have more kids live less because they spend more energy on having children.
What is the effect of chronic stress on ageing?
Not associated with long life.
What is DHEA?
Produced in adrenal glands and it is a steroid normone.
What is the effect of high levels of DHEA on ageing?
Higher survival.
What is the effect of melatonin on ageing?
Increases both life span but more likely to develop tumours.
