|
Hypothalamic-Pituitary-Ovary
Axis
In the presence of a GnRH pulse, the
pituitary and ovarian hormones exert mutual control over the
circulating levels of one another. The complex interactions between
pituitary and ovarian hormones involve forward control, positive
feedback, and negative feedback mechanisms, and serve to sustain
a self-perpetuating monthly endocrine cycle. The diagram below
outlines the causal relationships between the relative amounts
of key hormones of the menstrual cycle. Day one of the menstrual
cycle begins with menstruation, which occurs at the beginning
of the follicular phase. The menstrual cycle continues to ovulation,
which is followed by the luteal phase.
Click on any hormone in a rectangle
in the diagram below to learn more about its specific immediate
effects on the circulating levels of other hormones.
|
