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* In addition, pathological structures like ovarian cysts can be seen.
 
* In addition, pathological structures like ovarian cysts can be seen.
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== Headline text ==
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=== Endocrine Changes during the Oestrous Cycle ===
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* Hormones are secreted in a pulsatile manner and fluctuate considerably.
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* Just before onset of behavioural oestrus, there is a sharp rise in plasma oestrogens, particularly oestradiol.
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** Peak values occur at the beginning of oestrus
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** Levels decline to basal concentrations at ovulation
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* During the rest of the cycle, there are fluctuations but there is a discrete peak around day 6 of the cycle. 
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** Related to the first wave of follicular growth
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* Pre-oestrus rise in oestrogens stimulates the LH surge from the anterior pituitary.
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** This is necessary for follicular maturation, ovulation and maturation of the corpus luteum.
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* A second, less discrete peak occurs 24 hours after the LH surge.
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* Changes in progesterone concentrations mimic changes in the corpus luteum.
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* Progesterone levels peak 7-8 days after ovulation and decline quickly from day 18.
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* When progesterone levels fall to low basal levels, the negative feedback on the pituitary gland is removed.  This allows a sudden release of gonadotrophins.
    
= Links =
 
= Links =
    
[[Oestrous_Cycle_-Pharmacological_Manipulation_of_Oestrous_Cycles_-_Anatomy_%26_Physiology|Pharmacological Manipulation of Oestrous Cycles]]
 
[[Oestrous_Cycle_-Pharmacological_Manipulation_of_Oestrous_Cycles_-_Anatomy_%26_Physiology|Pharmacological Manipulation of Oestrous Cycles]]
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