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High levels of FSH indicate that the normal restricting feedback from the gonad is absent, leading to an unrestricted pituitary FSH production. FSH may contribute to postmenopausal osteoporosis and cardiovascular disease. [19] If high FSH levels occur during the reproductive years, it is abnormal. Conditions with high FSH levels include:
Many endocrinologists believe that the estrogen secretion of the dominant follicle has increased to a level that GnRH production is suppressed, which lowers the levels of LH and FSH. This slowdown in LH and FSH production leads to the atresia (death) of most of the recruited follicles, though the dominant follicle continues to mature. Estrogen ...
Reference ranges for estradiol, progesterone, luteinizing hormone and follicle-stimulating hormone during the menstrual cycle. Wikiversity, peer review verified 2013. Author: Mikael Häggström: Other versions: Derivative works of this file: Hormones estradiol, progesterone, LH and FSH during menstrual cycle pt.svg.png-format
The diagrams below take inter-cycle and inter-woman variability into account in displaying reference ranges for estradiol, progesterone, FSH and LH. Levels of estradiol (the main estrogen), progesterone, luteinizing hormone and follicle-stimulating hormone during the menstrual cycle. [88]
Estrogen levels peak towards the end of the follicular phase, around 12 and 24 hours. This, by positive feedback, causes a surge in levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This lasts from 24 to 36 hours, and results in the rupture of the ovarian follicles, causing the oocyte to be released from the ovary. [17]
This positive feedback loop causes LH to spike sharply, and it is this spike that causes ovulation. Following ovulation, LH stimulates the formation of the corpus luteum. Estrogen has since dropped to negative stimulatory levels after ovulation and therefore serves to maintain the concentration of FSH and LH.
The gonadotropins FSH and LH regulate the development of follicles, also known as folliculogenesis, in females, and the development of sperm in males. More specifically, the released FSH acts on ovarian granulosa and testicular Sertoli cells , while LH acts on ovarian theca and testicular Leydig cells .
This test can recognize the LH surge about 1-1.5 days prior to ovulation. Additionally, some ovulation prediction kits detect estrone-3-glucuronide. This is a breakdown product of estrogen and will have increased levels in the urine around the time of ovulation. This test is able to detect luteinizing hormone and estrone-3-glucuronide 90% of ...