From: A phase plane graph based model of the ovulatory cycle lacking the "positive feedback" phenomenon
Phases of growth & aging | GnRH rhythm and GnRHR availability | |||
---|---|---|---|---|
Leptin | GnRH | Female | Male | |
Children | low | secretion | minimal secretion | |
receptors | normal or increased pituitary receptors | |||
Early pubertal | normal | secretion | intermediate secretion | |
receptors | normal pituitary receptors | |||
Healthy adult | normal | secretion | low secretion from lutheolysis through follicular phase till the preovuatory days | stable |
high secretion from preovulatory days till lutheolysis | ||||
receptors | slowly up-regulated pituitary receptors during preovulatory days due to low GnRH exposure | stable | ||
rapid downregulation of pituitary receptors during the ovulatory surge due to GnRH overexposure | ||||
Healthy postmenopausal women | normal | secretion | low secretion due to estrogen deprivation | not applicable |
receptors | increased pituitary receptors due to low GnRH exposure leading to high FSH and LH secretion | |||
Anorexia nervosa | low | secretion | minimal secretion | |
receptors | normal or increased pituitary receptors |