Immobilization Does not Inhibit the Post-Coital Ovulatory Surge of Luteinizing Hormone in the Rabbit

Heparinized blood samples were obtained through an indwelling catheter in the central ear artery from sexually mature female New Zealand white rabbits after copulation. Immediately after 1 or 2 matings the female was transferred to a restraining cage; blood samples were taken at intervals while the animal was completely immobilized for 3-5 h or was only immobilized for blood withdrawal. Ovulation was detected by the presence of corpora lutea at laparotomy the following day. Plasma was analyzed for LH by established radioimmunoassay procedures. Immobilization did not inhibit ovulation or the pre-ovulatory surge of LH in either group. These data suggest that immobilization cannot inhibit the reflex release of LH in the female rabbit.