Lecture 14 - Endocrinology of Pregnancy, Labor, and Lactation Flashcards
Effect of hCG on male fetus?
Stimulates testosterone production by the testes of male fetus (development and decent of testes)
How do hCG and LH differ?
Few extra AAs on beta subunit of hCG
Is there a specific receptor for hCG?
NOPE, it binds to the LH receptor
Purpose of progesterone secretion by CP being stimulated by hCG?
Progesterone favors the maintenance of pregnancy because it maintains a non-contractile quiescent uterine myometrium (suppresses smooth muscle contractions of the uterus)
Why do hCG levels decrease back to 0 at week 10-12?
Because progesterone production shift from CP to placenta
Estrogen produced by placenta?
Estriol
Changes involving estrogen/progesterone in the last week of pregnancy?
- Progesterone levels start decreasing and # of myometrial receptors decreases
- Estrogen increases so larger effect than progesterone => favors uterine contractions
How does estrogen contribute to myometrium contractility during parturition?
CRH produced by placenta => fetal pituitary produces ACTH => fetal adrenal gland produces DHEA => DHEA diffuses through the placenta => placenta aromatase converts DHEA to local estrogen => increase in local estrogen/progesterone ratio => stimulation of prostaglandin synthase => production of prostaglandins PGF2-alpha => uterine contractions
What does DHEA stand for? What is it?
Dehydroepiandrosterone: androgen steroid hormone
What 4 factors stimulate uterine contractions?
- Oxytocin from mother’s posterior pituitary
- Catecholamines (NE and EPI) released by mother in response to pain/stress
- PGF2-alpha
- High local estrogen/progesterone ratio
Describe the feedforward regulation during parturition?
Uterine contractions => cervical stretch => stretch sensory receptors communicate through spinal cord synaptic relays to the oxytocin secreting centers of the hypo => increased oxytocin secretion by post pit + prostaglandins => uterine contractions => cycle
What is the functional unit of the breast allowing for milk production? Describe it.
Alveolus at the end of duct system
- Lumen: space into which breast milk is deposited
- Secretory columnar epithelial cells with prolactin receptors
- Layers of smooth muscle cells (myoepithelial cells) surrounding secretory cells with oxytocin receptors
How is milk secreted into the lactiferous ducts of the breast? What is this called?
Prolactin stimulates secretory cells to produce milk => milk is deposited into lumen => oxytocin stimules myoepithelial cells to contract => milk ejected into lactiferous ducts
= milk let-down reflex
Is there milk production during pregnancy? Why? What happens after delivery?
NOPE
Although estrogen stimulates prolactin, both estrogen and progesterone block the ability of prolactin to stimulate milk synthesis by the breast lobules
Delivery of placenta => decrease in estrogen/progesterone => ability of prolactin to stimulate milk production
Effect of estrogen on breasts during pregnancy?
Growth of ductile system