Enhanced frequency of chromosome aberrations in lymphocytes of male compared with female muntjacs after X-ray irradiation in vitro.

Recently, there has been considerable interest in the study of radiation-induced dicentrics and other chromosome aberrations in phytohaemagglutinin (PHA)-stimulated blood lymphocytes of various mammals, including man, with the aim of establishing a proper biological dosimetry for the assessment of genetic radiation hazards in human. These studies have revealed that the radiosensitivity of lymphocytes differs between species and even between individuals of the same species, but the cause(s) of these variations still remains unclear. The life-shortening response to whole-body X-ray irradiation is influenced by both age and sex of the individuals, but although age has been shown to have effects on chromosome aberration yields, in vitro, the influence of sex on the sensitivity of lymphocyte chromosomes to radiation-induced damage has not been reported. It is generally thought that sex does not influence the aberration yield within the limitation of measurements used in such studies. However, we report here a study of X-ray induced chromosome aberration in lymphocytes of Indian muntjac, in which the yield of dicentrics was found to be consistently greater in male than in female lymphocytes.