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203: The endocrine system > Endocrinology of ageing > Flashcards

Flashcards in Endocrinology of ageing Deck (27)
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1

Weight and lean body mass changes with age

Weight increases from mid-30s
- Stays stable 50-70

Lean body mass decreases
- 6-8%, from mid-30s

2

Diet trend with age

Decrease in intake of total energy

Protein intake increases

3

Insulin and glucose changes with age

Insulin and glucose increase
- Increase in insulin resistance
- Decrease in peripheral glucose uptake
- Increased prevalence of metabolic syndrome

4

Metabolic syndrome

Closely related conditions that increase the risk of CVD..

- Visceral obesity
- Dyslipidaemia
- Hypertension
- Hyperglycaemia

Increased prevalence as age increases due to an increase in insulin resistance.
- Generally more prevalent in males

5

Menopause
- Definition
- Symptoms
- Morbidities

Ovarian failure
- Drop in oestrogen
- Rise in FSH and LH
- Age 50 +/- 2 years

Symptoms
- Hot flushes
- Night sweats

Morbidities
- Osteoporosis
- Coronary heart disease
- Sexual dysfunction

6

Post-menopausal replacement therapy
- Benefits

Relieves the symptoms
- Decreases risk of osteoporosis and fractures

7

Post-menopausal replacement therapy
- Risks
- How to resolve it

Venous thrombolism

Breast cancer
- esp. used for >5 years

Endometrial cancer
- Unopposed E2 [only e2]

Resolved by only treating symptoms instead of preventing disorders
- Short term
- Low dose
- Started earlier.

8

Male gonadal axis with age

Gradual decrease in testosterone but with a wide range of normality.

Poor association with libido/ erectile dysfunction and testosterones.

- Decreased sexual function and muscle strength
- Increase risk of osteoporosis

9

Effects of testosterone treatment on bones

Increases bone mineral density
- But not their mechanical strength
- Fracture risk decreased by bisphosphanates.

10

Effects of testosterone treatment on body composition.

Increases lean body mass

Decreases fat mass

Increases muscle strength only in very high doses

11

Risks of testosterone treatment

Benign prostatic hypertrophy

Prostatic cancer

Erythropoiesis
- Increased RBC/ haemocrit

12

Changes in GH-IGF-1 axis with age

Decrease in GH and IGF-1

13

GH treatment
- Effects on body composition

Increases lean body mass [2kg]

Decreases fat mass [2kg]

Still not functional benefits.

No change for bone density or lipids

14

Risks and side effects of GH therapy

Risks:
Cancers- Breast, colon, prostate
- T2 DM

Side effects:
- Soft tissue oedema
- Arthralgia
- Carpel tunnel

15

Changes of cortisol levels and age.

Trough and average cortisol levels rise

Earlier time for trough and peak

16

Mechanism behind increased cortisol levels with age?

Sapolsky's glucocorticoid cascade hypothesis
- Decrease in hippocampal glucocorticoid and mineralocorticoid receptors [less negative feeback]

Affects hippocampal neurones= increase vulnerability to damage
- Decline in functions associated with hippocampus [memory, learning]

17

DHEAS and age

Declines.
- 5-10% of peak by 70-80

Not as important and as potent as androgens from testes in men

Non-specific marker
- Associations may not be causal [etc with cancer, T2 DM, CVD]

18

Thyroid function and age
- TSH
- T4, T3

Become slightly hypothyroid with age:

Slight TSH increase

Decreased peripheral conversion of T4 into T3.
= Decreased T3

19

Potential harms of T4 therapy

Osteoporosis

A Fib

Atherosclerotic coronaries

20

Effects of starvation
- Insulin
- Glucose
- Leptin

Decrease insulin
- Increased insulin sensitivity= decreased glucose.

Decreased levels of leptin
- Inhibits satiety, triggers starvation.

21

Leptin and starvation

Levels decrease to signal starvation
- Due to low body fat

Increases food intake and decreases energy expenditure

Decreases fertility

22

Starvation and androgens

Decreases fertility so
- Decreases FSH, LH, oestrogen, testosterone.

Amenorrhoea

Oestoporosis

23

Leptin and reproduction

When used to treat obesity, also:
- Increases gonadotrophin secretion
- Improvement reproductive organ maturation
- Induce puberty and fertility

24

Kisspeptin

Peptide that promotes release of GnRH from hypothalamus
- Especially at puberty

Can be inhibited or stimulated by oestrogen.

Reproduction and puberty modulated by leptin levels
- Leptin triggers stimulates
- So starvation inhibits Kisspeptin action

25

Starvation and GH

GH increased= GH resistance
- Decrease in IGF-1

Reversed with re-feeding

26

Starvation and cortisol

Increased levels

Many peaks

27

Starvation and thyroid function

Becomes hypothyroid
- Lowers basal metabolic rate to conserve energy

TSH and T4 low

Decreased T4 conversion to FT3

Increased T4 conversion to RT3