Endocrine signalling 3 + 4 Flashcards

1
Q

define and give examples

  1. autocrine
  2. paracrine
  3. endocrine
  4. neurohormone
  5. neurotransmitter
  6. pheromone
A
  1. cell - same cell type eg TFGb
  2. cell - different cell type eg oestradiol
  3. endocrine - blood eg LH
  4. hormone from neurone eg GnRH
  5. neurone to neurone eg serotonin
  6. via environment
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2
Q

human pheromone? 4 molecules

A

androsterone
androstenol
androstadienone
estratetraenol

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3
Q

hormones in TGFb family

A

inhibin A and B
activin
follistatin

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4
Q

most potent oestrogen in humans

A

17b-oestradiol E2

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5
Q

ways to module hormone action/half life

A
sulphation, glycosylation 
excretion 
biotransformation 
binding proteins eg SHBG
activetransport
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6
Q

negative feedback

A

inhibition of change

keeps homeostasis

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7
Q

positive feedback

A

stimulation of further change

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8
Q

example of positive feedback

A

oxytocin in childbirth

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9
Q

3 types of feedback loops

A

ultrashort - autocrine eg CRH
short - GNRH - GH
long via blood supply

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10
Q

photoperiodic control

A

light on RGC
retinohypothalamic tract
melanopsin +, pineal gland
SCN - reproduction, circadian

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11
Q

hormone levels peak in humans

A

early am = testosterone, cortisol
late day = insulin
night = melatonin, leptin, GH

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12
Q

circadian cycles and hormones

A

melatonin peaks at night
cortisol low at night, high in morning
GH high in sleep and TSH

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13
Q

seasonal fecundability

A

peaks in may and novemeber

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14
Q

humans vs sheep light

A

sheep - clear durational responses to photperiod

humans confused by artificial light

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15
Q

3 types of sex

A

genetic
gonadal
phenotypic

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16
Q

sex determinign region of Y chromosome

A

SRY

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17
Q

what hormone causes external appearance of penis and scrotum?

A

dihydrotestosterone

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18
Q

when is fetus bipotential?

A

<6 weeks

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19
Q

Guevedoces

A

Dominican republic - boys look like girls, only grow penis at puberty
deficient in SRD5A1 convert testosterone to DHT

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20
Q

guevedoces - prostate

A

small, led to development of 5alpha reductaseinhibitor finasteride - mimic lack of DHT

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21
Q

wolffian duct and mullerian duct - male and female

A

female - mullerian

male - wolffian

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22
Q

what hormone do sertoli cells secrete?

A

AMH

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23
Q

what does AMH do?

A

leydig cells differentiate and produce testosterone

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24
Q

paramesonephric ducts - males of females?

A

females

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25
Q

hypospadias by what week?

A

14

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26
Q

what is required to support leydig cells?

A

hCG and LH

27
Q

masculinisation programming window in humans

A

week 7-14

28
Q

cryptochordism

A

testes fail to descend

uncorrected = infertility

29
Q

fetal hormones for female germ cell humbers

A

E2, FSG, inhibin/activin

30
Q

primordial follicles formed by when?

A

28 weeks

31
Q

what % ovarian reserve at 35 years?

A

5

32
Q

surge centre - what is it?

A

inducing LH surge for ovulation

33
Q

surge centre - males and females

A

females - oestrogen and alpha FP no allowed into BBB

male - no development as testosterone makes E2 in brain

34
Q

3 parts which make seminal fluid

A

bulbourethral glands
prostate
seminal vesicle

35
Q

how long spermatozoa in epididymis?

A

15 days

36
Q

feedback control in men

A

GnRH pulsatile
LH pulsatile
T pulsatile

37
Q

androgen targets in men

A

CNS, penis, muscle, prostate, testis, hair, voice

38
Q

hypogonadism - features and causes

A
low sex drive and sperm count
loss of body hair 
diminished muscle mass
primary = testis
secondary = pituitary gland
39
Q

inhibin B in men

A

secreted by sertoli cells

40
Q

briefly explain reproduction in women

A

ovarian phase - follicular and luteal - LH peak ovulation
progesterone high luteal
uterus - proliferative and secretory

41
Q

LH function women

A

maintain dominant follcile

42
Q

FSH function women

A

follicular recruitment

43
Q

what do granulosa cells secrete?

A

oestradiol and inhibin B

44
Q

oestradiol and inhibin B female

A

oestradiol - support 2 sexual characteristics, negative feedback except late follicular phase
inhibin B - negative feedback FSH

45
Q

2 things CL secretes

A

inhibin A

progesterone

46
Q

inhibin A and progesterone function

A
A = negative feedback HPO
pro = maintain endometrium
47
Q

oestradiol production - cells needed and what happens?

A

theca cells and granulosa cells
theca cells convert cholesterol to androgen
through BM to granulosa cells
CYP19A1 turn andorgen into oestradiol

48
Q

when do theca cells appear?

A

secondary follicle

49
Q

when does FSH become essential?

A

day 2-16

2mm

50
Q

oestrogen targets women

A

breast, fat, CNS, bone

51
Q

what hormones rise with menopause?

A

LH and FSH

52
Q

3 types of androgen insensitivity syndrome

A

CAIS, PAIS, MAIS

complete, partial, mild

53
Q

AIS in males XY

A

inactivating mutation of androgen receptor
sertoli cells synthesise AMH
no uterus, open ended vagina

54
Q

Kleinfelters syndrome

A

XXY

long legs, gynaecomastia, testosterone deficiency, small testes, sparse facial hair

55
Q

congenital adrenal hyperplasia

A

enzyme deficiencies steroidogenesis

21OH deficiency

56
Q

21OH deficiency

A

elevated androgens
salt wasting
simple viriling
excess male hormones

57
Q

mutations of gonadotrophin receptors

A

activating - increase activity of LH/FSH
inactivating - decrease activity
polymorphisms

58
Q

why are gonadotrophin receptors important?

A

functional importance of hormone and its receptor

59
Q

Human FSHR mutations

A

activating - male
inactivating - various forms, mild to severe impairment of spermatogenesis
1 polymorphism

60
Q

FSHR mutations women

A

ovarian failure with amenorrhoea and infertility

61
Q

Human LHCGR mutations

A

activating - premature activation leydig cell
inactivating - mild undervirilisaion, lack of masculinisation
females - FSH more important

62
Q

LuRKO mouse - females

A

follicular maturation til antral
never ovulate
LH also needed for final follicular maturation

63
Q

LuRKO mouse - male

A

similar until 2 weeks PN
devoid of mature leydig cells
thin seminiferous tubules