Haemolysis following copulation in male rats.

In the course of a study on the effects of mating on plasma lh concentrations in the rat, a serendipitous finding was that plasma samples collected from male rats shortly after copulation often showed obvious evidence of haemolysis. These observations prompted a more detailed investigation. Adult Wistar rats were maintained under reversed lighting (lights on from 21.00 to 11.00 hours). Mating tests were carried out under observation in subdued lighting between 14.00 and 18.00 hours. Females were made highly receptive by the subcutaneous injection of 100 \g=m\gof oestradiol benzoate in oil 48 hr before tests were begun. Under these conditions, a normal ejaculatory series in the male rat consists of some ten to fifteen mounts with brief penile intromissions, separated by short intercopulatory intervals, over a period of 5 to 10 min. The series terminates with an ejaculation which is followed by a postejaculatory interval of several minutes during which no interest in the female is exhibited. In some tests, males were allowed to mate for 15 or 30 min, during which time