Activity of gonadotrophin surge-attenuating factor during the luteal phase in superovulated women

MacTavish, A.; Templeton, Allan

doi:10.1530/jrf.0.0970271

Cited by 13 publications

(12 citation statements)

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“…Several studies in vivo have provided evidence that the ovaries of superovulated women produce a nonsteroidal substance, named gonadotrophin-surge-attenuating factor (GnSAF), that attenuates the endogenous LH surge by reducing the response of LH to LHRH (Messinis and Templeton, 1989, 1991a. In these studies, the change in the response of LH to LHRH as a bioassay for GnSAF in vivo has shown that this factor is active during the follicular and the luteal phase of the human menstrual cycle (Messinis and Templeton, 1990;Messinis et al, 1993a). Although GnSAF has not yet been purified, studies in vitro have shown that GnSAF activity is present in steroidfree human follicular fluid and is different from that of inhibin (Busbridge et al, 1990;Fowler et al, 1990;Knight et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

Effect of an increase in FSH on the production of gonadotrophin-surge-attenuating factor in women

Messinis¹,

Lolis²,

Zikopoulos³

et al. 1994

Reproduction

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Gonadotrophin-surge-attenuating factor (GnSAF) is a putative nonsteroidal ovarian factor that is produced by FSH and that attenuates the LH surge in superovulated women. To study further the role of FSH in the production of GnSAF, 12 normally ovulating women were divided into two groups and investigated during two cycles: a cycle treated with placebo (control) and a cycle treated with FSH. In group 1 (n = 6), placebo (2 ml 0.9% normal saline) or FSH (450 iu) was injected i.m. on day 2 of the cycle (09:00 h). In group 2 (n = 6), placebo (2 ml 0.9% normal saline) or FSH (225 iu) was injected on the day (09:00 h) on which the dominant follicle was 14-15 mm in diameter, as measured by ultrasound (i.e. after the pituitary had been primed by endogenous oestrogen for several days). The response of LH over 30 min (delta LH) to an injection of 10 micrograms LHRH i.v. (bioassay for GnSAF in vivo) was investigated once a day in group 1, and 4, 8, 12 and 24 h after the injection of placebo or FSH in group 2. In group 1, delta LH was significantly attenuated 12 h after treatment with FSH compared with the control cycles, while serum oestradiol concentrations increased 24 h after the injection of FSH. The decrease in delta LH lasted for the period when the FSH concentration was increased (3 days). A significant decrease in the basal concentration of LH was correlated with the increase in the oestradiol concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Introductionmentioning

confidence: 99%

Effect of an increase in FSH on the production of gonadotrophin-surge-attenuating factor in women

Messinis¹,

Lolis²,

Zikopoulos³

et al. 1994

Reproduction

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“…Messinis’ group coined the term for this unknown factor as gonadotropin surge‐attenuating factor (GnSAF), and stated that it may affect the capacity of the pituitary to produce both FSH and LH in the presence of GnRH (Messinis and Templeton, ). The Messinis’ group also identified GnSIF/AF activity during the luteal phase of women undergoing controlled ovarian hyperstimulation and naturally cycling women (Messinis et al, ; Messinis et al, ). Indeed, they reported that GnSIF/AF levels were markedly decreased less than 2 hr after surgery in women undergoing hysterectomy and oophorectomy after four days of stimulation with FSH (225 IU/day), thus demonstrating its transient effect (Messinis et al, ).…”

Section: Evidence For Gnsif/afmentioning

confidence: 99%

Gonadotropin surge‐inhibiting/attenuating factors: A review of current evidence, potential applications, and future directions for research

Vega

Zarek

Bhagwat

et al. 2015

Molecular Reproduction Devel

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SUMMARY Animal studies in the 1980s suggested the existence of an ovarian hormone, termed gonadotropin surge-inhibiting/attenuating factor (GnSIF/AF), that modulates pituitary secretion of luteinizing hormone (LH). Given the importance of identifying regulatory factors of the hypothalamic-pituitary-ovarian axis and the accumulating data suggesting its existence, we conducted a comprehensive literature search using PubMed, Web of Science, Scopus, and Embase to identify articles related to GnSIF/AF. The search generated 161 publications, of which 97 were included in this study. Several attempts have been made to identify and characterize this hormone and several candidates have been identified, but the protein sequences of these putative GnSIF/AF factors differ widely from one study to another. In addition, while the RF-amide RFRP-3 is known foremost as a neuropeptide, some research supports an ovarian origin for this non-steroidal hormone, thereby suggesting a role for RFRP-3 either as a co-modulator of GnSIF/AF or as a gonadotropin-inhibiting factor in the hypothalamus (GnIH). Discovery of the KNDy neurons that modulate GnRH secretion, on the other hand, further encourages the search for substance(s) that modulate their activity and that indirectly affect LH secretion and the hypothalamic-pituitary-ovarian axis. While it has remained an elusive hormone, GnSIF/AF holds many potential applications for contraception, in vitro fertilization, and/or cancer as well as for understanding polycystic ovary syndrome, metabolic diseases, and/or pubertal development. In this review, we rigorously examine the available evidence regarding the existence of GnSIF/AF, previous attempts at its identification, limitations to its discovery, future directions of research, and potential clinical applications.

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“…This effect has been attributed to the putative ovarian hormone gonadotropin surge-attenuating/inhibiting factor (GnSAF/IF) [9] and is supported by data indicating that GnSAF/IF reduces GnRH self-priming, an important component of the LH surge, both in vivo [10] and in vitro [11,12]. Treatment with FSH stimulates the production of GnSAF/IF bioactivity in vivo in humans, monkeys, and rats [13][14][15][16][17][18][19][20]. However, GnSAF/IF bioactivity is not caused by elevated circulating FSH concentrations, because FSH administration to postmenopausal women does not reduce pituitary sensitivity to GnRH [21].…”

Section: Introductionmentioning

confidence: 99%

Follicle-Stimulating Hormone Stimulates Circulating Gonadotropin Surge-Attenuating/Inhibiting Factor Bioactivity in Cows1

Fowler¹,

Price²

1997

Biology of Reproduction

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This study aimed to determine whether superovulation in cattle stimulates gonadotropin surge-attenuating/inhibiting factor (GnSAF/IF) bioactivity, as it does in humans. Blood samples were collected from cows (n = 7 per treatment) at -4, 8, 20, 32, 44, 56, and 68 h after injections of saline, eCG, or FSH. Equal volumes of plasma at each treatment and time point were pooled, and GnSAF/IF and inhibin bioactivities were measured using an established rat pituitary cell culture bioassay. Plasma from saline- and eCG-treated cows had little effect on GnRH-induced LH secretion (116.3 +/- 8.3%-81.6 +/- 6.0% of control), while plasma from FSH-treated cows produced a time-dependent suppression of GnRH-induced LH secretion, falling to 64.6 +/- 4.0% of the control value at 56 h after first FSH injection (p < 0.001). The GnSAF/IF bioactivity from the 56-h plasma eluted at pH 5.73 by pseudochromatofocusing-similar to the GnSAF/IF isoelectric point value of 5.81 determined using serum from superovulated women. Plasma from FSH-treated cows reduced basal FSH secretion more than plasma from eCG-treated cows (to 55.5 +/- 5.7% and 63.2 +/- 6.6% of the control value, respectively, p < 0.01) although immunoreactive inhibin concentrations were similar between the two groups. We conclude that FSH, but not eCG, treatment causes a time-dependent production of circulating GnSAF/IF bioactivity in cattle.

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Activity of gonadotrophin surge-attenuating factor during the luteal phase in superovulated women

Cited by 13 publications

References 3 publications

Effect of an increase in FSH on the production of gonadotrophin-surge-attenuating factor in women

Effect of an increase in FSH on the production of gonadotrophin-surge-attenuating factor in women

Gonadotropin surge‐inhibiting/attenuating factors: A review of current evidence, potential applications, and future directions for research

Follicle-Stimulating Hormone Stimulates Circulating Gonadotropin Surge-Attenuating/Inhibiting Factor Bioactivity in Cows1

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