T1 L12 :EFFECTS OF AGE AND DIETON ENDOCRINE FUNCTION Flashcards

1
Q

what are the phenotypic effects of ageing

5marks

A
  • Increase fat mass, decreased visceral fat
  • Sarcopaenia
  • Decreased Bone mineral density
  • Decreased QOL / mood
  • increased risk cardiovascular disease
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2
Q

what are the 2 main features of ageing

A

Hypogonadism / growth hormone deficiency / aging

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3
Q

what are the nutritional stats with age ( Weight, lean body mass and Diet )

A

1- Increase from mid-30s
stabalise 50 – 70

2-Decrease by 6-8% / decade from mid-30s

3-Diet - Trend towards decrease in the intake total energy & protein with increasing age

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4
Q

what occurs to your insulin and glucose levels with age

A

increased insulin and glucose conc with age.

More insulin resistance and so less peripheral glucose uptake

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5
Q

What happens to metabolic syndrome with age

A

Prevalence Increases

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6
Q

what are the 2 main areas of gonadal axis research

A

Menopause

Testosterone

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7
Q

what is menopause

A

Ovarian failure

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8
Q

what occurs to estrogen levels during menopause

pre and post

and what happens to E2 LH and FSH

A

Pre-menopausal: cycling

Post-menopausal: very low constant levels:

-decreased E2, but increased LH and FSH

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9
Q

what are the symptoms of menopause

and what is the mean duration

A

Hot flushes, night sweats

Median duration of menopausal symptoms 7 years

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10
Q

what causes morbidity in menopause

A

increased osteoporosis

increased CHD

increased sexual dysfunction

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11
Q

what is HRT

A

Hormone replacement therapy - used as a treatment of symptoms of disorders associated with oestrogen deficiency like osteoporosis )

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12
Q

what are the benefits of POST-MENOPAUSAL HRT

A

decreased osteoporosis and therefore fracture risk

Decreases menopausal symptoms

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13
Q

what are the risks of POST-MENOPAUSAL HRT

A

-increase in venous thrombo-embolism

-Increase in breast Ca (small)
esp > 5 years

  • Increase in endometrial Ca
  • –if use unopposed E2
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14
Q

what occurs in the male gonadal axis

and give a rough statistic of what happens at 75 years compared with 25

A

a gradual decrease in testosterone associated with increasing age

at 75 years 2/3rds that of @ 25 years

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15
Q

what are the effects of low testosterone in men

A

poor libido

increase in osteoporosis

decrease in muscle strength

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16
Q

what are the effects of testosterone treatment on bone

A

increase in bone mineral density of hypogonadal but bisphosphonates work independent of the androgen status

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17
Q

what happens to the body composition with the male gonadal axis with testosterone treatment

advantages

A

decrease fat mass

increase in lean mass

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18
Q

what is there little to no evidence of testosterone treatment improving

A

Atherosclerosis

sexual function

cognitive function

Mood/quality of life

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19
Q

what does weight loss improve

A

levels of testosterone

20
Q

what happens to the GH-IGF-I axis as you age

A

GH and IGF-I decreases with age

but still wide variation

21
Q

what does GH treatment do to body composition

A
  • increases  lean body mass

- decreases fat mass

22
Q

what doesn’t change significantly with GH treatment

A
  • Bone mineral density

- Lipids

23
Q

what are the risks with GH treatment

A
  • Cancer I increased IGF-I assoc with non-smoking cancers-prostate, coon, breast
  • Increase in T2 DM
24
Q

what are the side effects of GH treatment

A
  • Soft tissue oedema
  • Arthralgias
  • Carpal tunnel syndrome
25
Q

what happens with cortisol as you age

A

there is an increase in the levels- trough levels also increase

phase advance of diurnal rhythm (Troughs and peaks occur earlier)

26
Q

what is the Sapolsky’s glucocorticoid cascade hypothesis

A
  • decrease in hippocampal glucocorticoid & mineralocorticoid receptors
  • decrease sensitivity to glucocorticoid negative feedback
  • increase in glucocorticoids

leading to hippo campal neurons vulnerable to damage
‘feed forward cascade’

27
Q

what happens to DHEAs with age

A

they decrease with age

(helps to protect against CHD)

therefore a low DHEA: low]:cortisol ratio found in cancer, inflammatory diseases, T2DM, CV disease

28
Q

what does DHEA have no evidence of effect on

A
  • body comp
  • physical performance
  • Insulin sensitivity
29
Q

what does increasing age do to thyroid hormone biomarkers

A

increase in TSH
T4 same
decrease in T3
decrease in peripheral T4-T3 conversion

30
Q

what does starvation do to gluc-insulin levels

A

It decreases them and increases insulin sensitivity

31
Q

what is Leptin produced by

A

It’s produced by white adipose tissue

32
Q

what does starvation signal do to leptin and to hypothalamus

A

It signals energy availability

Decrease leptin- Increase food uptake and decreased energy expenditure

decreased leptin leads to decrease fertility

33
Q

what does starvation do to oestrogen and testosterone

A

It decreases LH and FSH and oestrogen and testosterone

it decreases fertility an increases hypothalamic amenorrhoea

34
Q

what is the evidence of metabolism and reproduction

A

OB Ob mouse was hyperphagic and obese

  • had low gonads
  • infertile
  • didn’t mature sexually
35
Q

what happened to gonads and weight when obob mouse was given Leptin

(+puberty and fertility)

A

Reduced obesity

restore GN secretion

induce puberty

restore fertility

36
Q

what is amenorrhoea

A

an abnormal absence of menstruation.

37
Q

is amenorrhoea due to the hypothalamus

if so why

A

yes

Sometimes the hypothalamus stops producing GnRH, which, in turn, will reduce the amount of other hormones produced (FSH, LH, and estrogen). Ovulation and menstruation stop, resulting in infertility.

38
Q

what is kisspeptin

A

A GnRH secretagogue

39
Q

what does kisspeptin neurons do

A

KISS1 neurons highly responsive to oestrogen, implicated in both + and – central feedback of sex steroids on GnRH production
Metabolic influences on reproduction mediated by leptin via the kisspeptin system
Puberty
Reproduction

40
Q

what does leptin do to kisspeptin

A

Leptin promotes GnRH function via an indirect action on forebrain neurons. We tested whether leptin deficiency or leptin resistance due to a high-fat diet (HFD) can regulate the potent reproductive neuropeptide kisspeptin.

41
Q

what does starvation do to the GH/IGF axis

A

GH resistance

increased GH and a decrease in IGF-I
due to

downregulation of hepatic GH receptor

42
Q

is the effect of GH/IGF axis reversible

A

yes with re-feeding

43
Q

what does starvation do to cortisol levels

A

Pulsatile Rhythm

44
Q

what does starvation do to thyroid biomarker levels

A

It decreases TSH and T4

leading to less conversion to T3 but more to rT3 (inactive form)

45
Q

consequences of starvation on thyroid gland

A
  • Lower basal metabolic rate

- Conserve energy