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Updated: Feb 13, 2026

Dual Somatic Recordings from Gonadotropin-Releasing Hormone GnRH Neurons Identified by Green Fluorescent Protein GFP in Hypothalamic Slices
Published on: February 23, 2010
Gonadotropin Surge-Attenuating Factor: A Nonsteroidal Ovarian Hormone Controlling GnRH-Induced LH Secretion in the
Ioannis E Messinis1, Christina I Messini1, George Anifandis1
1Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece.
Abstract:
Gonadotropin surge-attenuating factor (GnSAF) is a nonsteroidal ovarian substance, which attenuates the endogenous LH surge in superovulated women. Different molecular sequences have been found, but only one of them has shown substantial homology to a known substance of the human genome. A molecular mass of 12.5kDa showing identity to the carboxyl-terminal fragment of human serum albumin and expressing GnSAF bioactivity in vitro has been identified. It has been suggested that in the normal menstrual cycle the in vivo bioactivity of GnSAF increases under the influence of the intercycle rise of FSH. GnSAF is considered the "missing link" between the ovaries and the hypothalamo-pituitary system, maintaining the pituitary in a state of low responsiveness to GnRH in the early- to midfollicular phase of the cycle. A marked decline in GnSAF bioactivity in the late follicular phase facilitates the onset and the full expression of the midcycle LH surge.
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