Luteal Phase Flashcards
What are the two subphases of the luteal phase?
metestrus and diestrus
What are the concentration trends of the major hormones (P4, E2, LH, and FSH) during metestrus?
P4 concentrations begin to rise, E2, LH, and FSH have reached their lowest concentrations
What are the concentration trends of the major hormones (P4, E2, LH, and FSH) during diestrus?
P4 concentrations reach their peak, E2, LH, and FSH have are at their lowest concentrations
What type of luteal cells do theca cells become and how?
when the follicle ruptures, they undergo hyperplasia, and turn into small luteal cells
What type of luteal cells do granulosa cells become and how?
when the follicle ruptures, they undergo hypertrophy and fill up with cholestoral to become large luteal cells
What are the two general facets of luteolysis?
the finite lifespan of the LLCs and SLCs and a hormone that kills the LLCs and SLCs
What is CA?
corpus albicans - degenerated corpus luteum
Which cells are the major source of progesterone during the luteal phase, and why are they the major source?
Granulosa cells that become LLCs because LH levels, which also synthesize P4, are low during the luteal phase
What is the function of oxytocin in luteolysis?
Oxytocin acts locally on the uterus via the vascular counter-current exchange and stimulates the synthesis of PGF 2 alpha
What is the function of PGF 2 alpha in luteolysis?
PGF2 alpha directly activates apoptosis by activating is cognate GPCR that subsequently facilitates a calcium influx - this activity speeds the degeneration of the CL and a return to the follicular phase
What are the five feedback mechanisms of the luteal phase?
1) P4 prevents GnRH release at the hypothalamus
2) P4 prevents GnRH activity at the AP
3) P4 stimulates oxytocin-R synthesis in the endometrium
4) Oxytocin stimulates PGF 2 alpha synthesis in the endometrium
5) PGF 2 alpha stimulates oxytocin release from the CL
