Inhibition of multiple ovulation in hypophysectomized hens treated with gonadotrophins

Administration of PMSG or FSH to hypophysectomized hens prevented the multiple ovulation (2-3 ova) induced by an OIH. Inhibition of multiple ovulation did not occur when FSH was injected 1/2-2 hr before the OIH injection. The results are believed to support the theory that withdrawal of FSH stimulation sensitizes a follicle to the OIH in the normal hen.