Animal Science 434Animal Science 434
Lecture 11: The Luteal Phase of the Estrous Cycle and the Menstrual Cycle in Primates
Lecture 11: The Luteal Phase of the Estrous Cycle and the Menstrual Cycle in Primates
0
2
4
6
8
10
12
14
0 2 4 6 8 10 12 14 16 18 20 22
Day of the Estrous Cycle
Relative Progesterone Level (Blood)
Lu
teo
lysi
s
P4
Production(Diestrus)
P4
Production(Diestrus)
CLFormation(Metestrus)
Rel
ativ
e P
rog
este
ron
e L
evel
s (B
loo
d)
Fo
llicu
lar
Ph
ase
Luteal Phase
Ovulation Ovulation
• steroid synthesis– progesterone
• collagenase– theca interna
• present 1-3 days following ovulation
• blood vessels in follicle wall rupture
• walls collapse
• cells intermix
• old basement membrane becomes connective tissue of CL
• increases in size– papilla forms
• composed of cells from the granulosa and theca interna
• progesterone production increases
• a small cavity may be present where the folliclular antrum was present
Luteal TissueLuteal Tissue
• Large cells from granulosa
• Small cells from the theca interna
• Large cells from granulosa
• Small cells from the theca interna
Mitochondria
SecretoryGranules
- Oxytocin- Relaxin
Functional Capability of CLFunctional Capability of CL• the number of luteal cells
– large cells undergo hypertrophy (3 fold)– small cells undergo hyperplasia (5 fold)
• vascularization of CL– Initiated by angiogenic factors from
follicle– Vascularity effects CL steroid synthesis
and delivery of hormones
• Insufficient CL function– Failure to maintain pregnancy– Important in domestic animals
• the number of luteal cells– large cells undergo hypertrophy (3 fold)– small cells undergo hyperplasia (5 fold)
• vascularization of CL– Initiated by angiogenic factors from
follicle– Vascularity effects CL steroid synthesis
and delivery of hormones
• Insufficient CL function– Failure to maintain pregnancy– Important in domestic animals
Progesterone Targets
Aveolar Development
Blocks EstrusNegative Feedback
Progesterone Production by Luteal Cells
LuteolysisLuteolysis
• Uterus
• PGF2
• Oxytocin
• Uterus
• PGF2
• Oxytocin
Luteolysis in Cows,
Ewes, Sows
LuteolysisLuteolysis
• Uterus
• PGF2
• Oxytocin
• Uterus
• PGF2
• Oxytocin
Prostaglandin F2Control of Luteolysis
Progesterone fromCL stimulatesproduction of uterine PGF2afterday 15 in cow
Uterine Horn
UterineVein
Prostaglandin synthesisby uterine endometriumis released into the uterine vein.
Oviduct
Ovary
CorpusLuteum
PGF2 is picked up by ovarian artery through counter current exchangeand delivered back to theovary where it causeslysis of the CL
Uterine ArteryUterine Artery
Ovarian Pedicle
PGF
PGF into Artery
Luteolysis in Mares
50% of CL’s maintained
CL regresses on day 17
%50 of CL’s maintained
CL maintained >30 days
Blood Supply to Uterus and Ovary in the Mare
PGF Not Effective (Cow, Ewe, Mare)PGF Not Effective (Cow, Ewe, Mare)
PGF Not Effective (Sow)PGF Not Effective (Sow)
LuteolysisLuteolysis
• Uterus
• PGF2
• Oxytocin
• Uterus
• PGF2
• Oxytocin
Relationship of Oxytocin and PGF2
Uterus
Ovary
CL
PGF2
Anterior Pituitary
Posterior Pituitary
Oxytocin
LuteolysisLuteolysis
• decreased blood flow
• cellular response– apoptosis– progesterone synthesis
• Immune response– Lymphocytes– Macrophages
• decreased blood flow
• cellular response– apoptosis– progesterone synthesis
• Immune response– Lymphocytes– Macrophages
ER
IP3
Ca++
LuteolysisLuteolysis
• decreased blood flow
• cellular response– apoptosis– progesterone synthesis
• Immune response– Lymphocytes– Macrophages
• decreased blood flow
• cellular response– apoptosis– progesterone synthesis
• Immune response– Lymphocytes– Macrophages
Menstrual CycleMenstrual Cycle
FSHLHLH
EstradiolEstradiol
ProgesteroneProgesterone
FollicleOvulation
Corpus LuteumCorpus
Albicans
2 4 6 8 10 14 16 18 20 22 24 26 28 212
Anterior Pituitary
Hormones
Ovarian Hormones
Ovary
UterineEndo-
metrium
RecruitmentSelectionDominance
Recruitment
Luteolysis in the Primate
• Does not require the uterus
• CL lifespan in the human is 12-14 days unless pregnancy occurs– In the absence of pregnancy, CL self
destructs
FSHLHLH
EstradiolEstradiol
ProgesteroneProgesterone
FollicleOvulation
Corpus Luteum
2 4 6 8 10 14 16 18 20 22 24 26 28 212
Anterior Pituitary
Hormones
Ovarian Hormones
Ovary
UterineEndo-
metrium
Men
ses
Men
ses
Men
ses
Men
ses
5days
5days
5 days
5 days
Fo
llicu
lar
Ph
ase
Fo
llicu
lar
Ph
ase
9 days9 days
Lu
teal
Ph
ase
Lu
teal
Ph
ase
14 days14 days
Variation in Menstrual Cycle Length
35-daycycle
Ovulation
14 days14 days
Menses Foll. Phase Luteal Phase Menses
28-daycycle Menses Luteal Phase MensesFoll. Phase
25-daycycle Menses Foll. Phase MensesLuteal Phase
14 days14 days
5 days5 days
5 days5 days
5 days5 days
6 days6 days
9 days9 days
16 days16 days 14 days14 days
BreastTenderness
BreastTenderness
Menstural Cycle Length
• AGELength
15 - 19 year olds 35 days 30 year olds 30 days 35 year olds 28 days
Variation More in teenagers Less in women in peak reproductive years
HypothalamusHypothalamus
GnRHGnRH
AnteriorPituitary
AnteriorPituitary
CL FollicleOvary
LH, FSH
LH LH, FSH
Inhibin (-)
EstradiolEstradiol (-)
(-)
ProgesteroneProgesterone
HypothalamusHypothalamus
GnRHGnRH
AnteriorPituitary
AnteriorPituitary
FollicleOvary
LH, FSH
LH, FSH
Inhibin (-)
EstradiolEstradiol (+)
Est
rad
iol
pg
/ml
LH
m
IU/m
l FS
H m
IU/m
lP
rog
. ng
/ml