Ah. Balen et al., IN-VITRO BIOACTIVITY OF GONADOTROPIN SURGE ATTENUATING FACTOR IS NOT AFFECTED BY AN ANTIBODY TO HUMAN INHIBIN, Journal of Reproduction and Fertility, 104(2), 1995, pp. 285-289
The effect of anti-inhibin antibodies on gonadotrophin surge attenuati
ng/inhibiting factor (GnSAF/GnSIF) and its effect on gonadotrophin sec
retion in a pituitary cell bioassay were determined by culturing rat p
ituitary cells in a serum-free medium to which inhibin and a partially
purified preparation of gonadotrophin surge inhibiting factor (GnSIF)
were added. The samples were treated with an anti-inhibin antiserum a
nd basal and GnRH-stimulated FSH and LH secretion were measured by rad
ioimmunoassay of the culture supernatant. Inhibin had a dose-dependent
inhibitory effect on both basal and GnRH-stimulated FSH secretion and
also on GnRH-stimulated LH secretion. Anti-inhibin antibody blocked t
he inhibition of FSH secretion, except at the highest two doses of hum
an inhibin (1.25 ng ml(-1), P=0.04; 2.5 ng ml(-1), P=0.0004). The GnSI
F preparation inhibited basal and GnRH-stimulated FSH and GnRH-stimula
ted LH secretion and was not affected by the anti-inhibin antibody. Th
e novel hormone, GnSIF, is different from inhibin.