Sunday, June 26, 2011
Endocrine Aspects of Menstrual Cycle
9:12 AM | 
Posted by
Arif Siregar
Now note that in the process of ovulation there must be cooperation between the cerebral cortex, hypothalamus, pituitary, ovaries, thyroid gland, gland suprarenalis, and other endocrine glands. Which play an important role in the process is the relationship the hypothalamus, pituitary, and ovary (hypothalamic-pituitary-ovarian axis). According to the neurohumoral theory adopted today, the hypothalamus control the secretion of gonadotropin hormone secretion by adenohipofisis through neurohormon delivered to cells adenohipofisis through a special portal circulation. The hypothalamus produces factors that had to be isolated and called Gonadotropin Releasing Hormone (GnRH) because it can stimulate the release of luteinizing hormone (LH) and Follicle Stimulating Hormone (FSH) from the pituitary. Does the hypothalamus to produce FSH-Releasing Hormone (FSH-RH), separated from LH-Releasing Hormone (LH-RH), not to mention must be because FSH-RH can not be isolated.
Normal menstrual cycle can be properly understood by dividing it into 2 phases and 1 point, namely the follicular phase, during ovulation, and luteal phase. Changes in hormone levels throughout the menstrual cycle caused by the feedback mechanism between steroid hormone and gonadotropin. Estrogen causes negative feedback on FSH, while LH estrogen to cause negative feedback if the levels are low, and positive feedback if the levels are high.
Not long after menstruation began, in early follicular phase, several follicles to grow by increasing the influence of FSH. The increase in FSH is due to corpus luteum regression, so that the steroid hormone is reduced. With the development of follicles, estrogen production increases, and these suppress FSH production. Follicles that will ovulate protect themselves against the atresia, whereas other follicles atresia. At this time of LH also increased, but its role at this level only helps estrogen production in the follicle. Rapid follicle development in the late follicular phase when FSH begins to decline, indicating that the follicle end after estrogen levels in plasma clearly rising. Estrogen initially rising gradually, then rapidly reached a peak. This provides positive feedback terhada cyclic center, and with the LH surge (LH-surge) in mid-cycle, resulting in ovulation. LH rises was settled for approximately 24 hours and decreased at the luteal phase. The mechanism is not yet clear decrease in LH. Within a few hours after the LH increases, decreases estrogen and perhaps this is the cause of LH was decreased.
Not long after menstruation began, in early follicular phase, several follicles to grow by increasing the influence of FSH. The increase in FSH is due to corpus luteum regression, so that the steroid hormone is reduced. With the development of follicles, estrogen production increases, and these suppress FSH production. Follicles that will ovulate protect themselves against the atresia, whereas other follicles atresia. At this time of LH also increased, but its role at this level only helps estrogen production in the follicle. Rapid follicle development in the late follicular phase when FSH begins to decline, indicating that the follicle end after estrogen levels in plasma clearly rising. Estrogen initially rising gradually, then rapidly reached a peak. This provides positive feedback terhada cyclic center, and with the LH surge (LH-surge) in mid-cycle, resulting in ovulation. LH rises was settled for approximately 24 hours and decreased at the luteal phase. The mechanism is not yet clear decrease in LH. Within a few hours after the LH increases, decreases estrogen and perhaps this is the cause of LH was decreased.
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