Endocrinology of pregnancy Flashcards
hCG
function + structure
- α & β subunits
- α subunit identical to LH, FSH and TSH
Function
- Acts on LH receptors on corpus luteum
- Maintains corpus luteum
- Stimulates DHEA production in fetal adrenal
In males – stimulates testosterone → masculinisation
When can hCG be dected and when does it stop
in early pregnancy doubles every 48 hrs
detected days 8-12 + stops around 12 weeks
- clinically used to measure if there’s problem
- if it doesn’t rise by 60% in 48 hours their can be problems
- progesterone may be given early pregnancy
What synthesises hCG
synctitrophoblast
What happens if you block hCG via antibodies
block pregnancy
how?
hormone keeps progesterone levels good, no progesterone no endometrium to implant into
Progestrone
function, where produced
Initially produced from corpus luteum
Produced from cholesterol by syncytiotrophoblast – the placenta takes over from corpus luteum ~6-8 weeks
Function
-maintains pregnancy
-affects myometrium: how -> decreses syntheise of contractile protiens, via progestrone b recpetor
-inhibits expression of oxytoxin receptors on myometrium during pregnancy
-Decidual transformation/maintenance (you know viilli, spiral arteries, Immune suppressive effect)
How can oestrogen be made
- cholesterol taken and converted in placenta to from pregnalalone to progesterone
- progesterone can be processed by fetal adrenal or liver, to make 17, OH then converted to DHEA
- DHEA can go back to the mother that is a conjugated sulfate
- so mum can take in DHEA, and convert it into oestrogen which makes de conjugated
What are the three oestrogens and their roles
- Oestrone, E1: Predominates after menopause
- Oestradiol, E2: Regulates menstruation
- Oestriol, E3: Pregnancy-specific
What happens to oestrogen during pregnancy
rises throughout pregnancy
Oestriol production predominates (oestriol»_space; oestrone & oestradiol)
Produced co-operatively by the placenta and fetus
What form is oestrogen in
- hormones bound to carrier proteins
- and are sulfated means they are inactive
- and then they are deconjugated in placenta
What is the role of oestrogen after implanation
**Vascular changes
**
- Vasodilation – increase uterine blood flow
- Increase in prothrombotic mechanisms
- Activated Protein C resistance increases
- Antithrombin III and Protein S decrease
- slight increase in risk of thrombosis in pregnancy
**Increase contractile-associated proteins
**– Gap junctions (e.g. Connexin 43), Oxytocin & its receptors, Myometrial glycogen stores, Breast development (for lactation)
**Metabolism
**
- reduces peripheral glucose uptake
- increases cholesterol & triglycerides – decreases HDL
Breast development
When does placental growth hormone (PGH) secretion start
Secretion starts from 15-20 weeks from syncytiotrophoblast & EVTs
What is PGH role
- Stimulates maternal gluconeogenesis & lipolysis
- aids nutrition across placenta
What do PGH levels correlate with
Non pulsatile
So Levels correlate with placental size
- big fetus big placneta
- levels correlate with placenta size
What hormones are related to human placental lactogen
GH & PRL
Where is human placental lactogen produced and what is its function
-Produced by the syncytiotrophoblast
Stimulates gluconeogenis and lipolysis
What happens to HPL levels
Rises as hCG falls
What is the role of HPL
-Development of acinar cells in mammary glands
- ready for milk production
- Aids fetal nutrition
Suppresses action of insulin in mother – “acts as metabolic screwdriver”
- increases blood glucose levels – more available to the fetus
- glucose goes across on a gradient
- hormone allows gradient to be maintained
- stops peripheral uptake of glucose
- which can lead to insulin sensitivity
- mobilises maternal FAs to meet fetal demand
Increases risk of GD
Large amounts in maternal blood – little reaches fetus
- IGF -1 produced by the liver which leads to insulin resistance and break down of fats
- so you get an increase of glucose to the fetus, and steroids synthesis happens on placenta
What is the structure of relaxin and where is it produced
Structure
Peptide hormone ~6 kDa related to insulin
Proudced by
produced by corpus luteum
-can be made during menustration