The Effect of Synthetic Oxytocin Upon Seminal Characteristics and Sexual Behaviour in Male Rabbits

In male rabbits the composition of the ejaculate changes, and the willingness to copulate increases upon intravenous injection of purified extract of the posterior lobe of the pituitary (Kihlström & Melin, 1963; Melin & Kihlström, 1963). These effects were ascribed to the oxytocic activity of the extract which, however, may contain small amounts of other hormones as impurities. For this reason the experiments have been repeated, using synthetic oxytocin (Syntocinon, Sandoz). Eight sexually mature rabbits of the Bourgogne breed, none of them more than 2 years old, were studied from 10th February to 27th May. The bucks were kept in individual cages throughout the experimental period and were all given the same kind of food once a day at a given time. The temperature in the animal house varied between + 16 and +18 ° C. Before the start of the