title: In vitro bioactivity of gonadotrophin surge attenuating factor is not affected by an antibody to human inhibin.
abstract: The effect of anti-inhibin antibodies on gonadotrophin surge attenuating/inhibiting factor (GnSAF/GnSIF) and its effect on gonadotrophin secretion in a pituitary cell bioassay were determined by culturing rat pituitary 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 and basal and GnRH-stimulated FSH and LH secretion were measured by radioimmunoassay 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 the inhibition of FSH secretion, except at the highest two doses of human inhibin (1.25 ng ml-1, P = 0.04; 2.5 ng ml-1, P = 0.0004). The GnSIF preparation inhibited basal and GnRH-stimulated FSH and GnRH-stimulated LH secretion and was not affected by the anti-inhibin antibody. The novel hormone, GnSIF, is different from inhibin.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D001681:Biological Assay; D002478:Cells, Cultured; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D042341:Gonadal Hormones; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007265:Inhibins / Q000276:immunology* / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism; D011506:Proteins / Q000378:metabolism* / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000911:Antibodies, Monoclonal; D042341:Gonadal Hormones; D011506:Proteins; C080538:attenuin; D007987:Gonadotropin-Releasing Hormone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone