Although first described in the 1980 s,FSH was found to stimulate the ovarian production of an uncharacterized hormone known by its specific effect of reducing pituitary responsiveness to GnRH,named as gonadotropin su...Although first described in the 1980 s,FSH was found to stimulate the ovarian production of an uncharacterized hormone known by its specific effect of reducing pituitary responsiveness to GnRH,named as gonadotropin surge-attenuating factor(GnSAF).People has been proposing that the main role of GnSAF is probably the negative regulation of pulsatile LH secretion as an antagonist of estrogen,mainly elevate during the first half of the follicular phase,and decline before ovulation,indicating a critical role in the regulation of folliculogenesis and oestradiol secretion.Previous studies have revealed that GnSAF only exist in granulose cells of small follicle,stimulated by FSH.The bioactivity of GnSAF is consistent with the diameter of follicle,the highest in 11 mm follicle in stimulating cycles and 6-8 mm follicle in nature cycles.Though to date there have been five main published attempts to characterize GnSAF,yielding amino acid sequences on four occasions,it has still not been convincingly characterized and no published candidate amino acid sequences conclusively relate to GnSAF bioactivity.Because premature luteinization occurs more frequently in older or poor responder patients,defective production of GnSAF may be involved.Our study was to test this phenomenon by adding estrogen in luteal transition phase ahead of IVF/ICSI stimulating cycle,to observe the hormone profile,clinic outcome and probably premature luteinization.The results indicate when FSH level was repressed by estrogen application during the luteal transition phase,more gonadotropin,longer stimulation may be needed,and progesterone rise may result from the premature releasing of LH,that could be a negative affect on GnSAF bioactivity on ovulation.展开更多
The neurotransmitter theory of the hypothalamicpituitary was first introduced in 1949.These nuclei located in the hypothalamic area secret factors such as GnRH,amino-acids,neuropiptides,growth factors,and oncogenes,wh...The neurotransmitter theory of the hypothalamicpituitary was first introduced in 1949.These nuclei located in the hypothalamic area secret factors such as GnRH,amino-acids,neuropiptides,growth factors,and oncogenes,which play important roles as messengers affecting target cells in the pituitary gland as well as the entire body through the endocrine,para-endocrine,self-endocrine,and neural endocrine systems.The release rhythm of the neural hormones is essential for their function.Human GnRH was identified as being 18.9 kb in length.Its receptor belongs to the G protein-coupled receptor family,which initiates the signal transduction pathway and reproductive function in pituitary and other cells.Dysfunction of the system may result in a group of disorders in reproductive endocrinology or infertility.There are still many unknown mechanisms regarding GnRH and ovulation induction.We need to understand more about them.展开更多
文摘Although first described in the 1980 s,FSH was found to stimulate the ovarian production of an uncharacterized hormone known by its specific effect of reducing pituitary responsiveness to GnRH,named as gonadotropin surge-attenuating factor(GnSAF).People has been proposing that the main role of GnSAF is probably the negative regulation of pulsatile LH secretion as an antagonist of estrogen,mainly elevate during the first half of the follicular phase,and decline before ovulation,indicating a critical role in the regulation of folliculogenesis and oestradiol secretion.Previous studies have revealed that GnSAF only exist in granulose cells of small follicle,stimulated by FSH.The bioactivity of GnSAF is consistent with the diameter of follicle,the highest in 11 mm follicle in stimulating cycles and 6-8 mm follicle in nature cycles.Though to date there have been five main published attempts to characterize GnSAF,yielding amino acid sequences on four occasions,it has still not been convincingly characterized and no published candidate amino acid sequences conclusively relate to GnSAF bioactivity.Because premature luteinization occurs more frequently in older or poor responder patients,defective production of GnSAF may be involved.Our study was to test this phenomenon by adding estrogen in luteal transition phase ahead of IVF/ICSI stimulating cycle,to observe the hormone profile,clinic outcome and probably premature luteinization.The results indicate when FSH level was repressed by estrogen application during the luteal transition phase,more gonadotropin,longer stimulation may be needed,and progesterone rise may result from the premature releasing of LH,that could be a negative affect on GnSAF bioactivity on ovulation.
文摘The neurotransmitter theory of the hypothalamicpituitary was first introduced in 1949.These nuclei located in the hypothalamic area secret factors such as GnRH,amino-acids,neuropiptides,growth factors,and oncogenes,which play important roles as messengers affecting target cells in the pituitary gland as well as the entire body through the endocrine,para-endocrine,self-endocrine,and neural endocrine systems.The release rhythm of the neural hormones is essential for their function.Human GnRH was identified as being 18.9 kb in length.Its receptor belongs to the G protein-coupled receptor family,which initiates the signal transduction pathway and reproductive function in pituitary and other cells.Dysfunction of the system may result in a group of disorders in reproductive endocrinology or infertility.There are still many unknown mechanisms regarding GnRH and ovulation induction.We need to understand more about them.
