title: An analytical approach to the induction of translocations in the spermatogonia of the mouse.
abstract: An analysis of a series of data providing a comprehensive impression of the effect of radiation on the induction of translocations in the spermatogonia of the mouse is presented. It is assumed that the spermatogonial stem-cell population is made up of a sensitive and resistant compartment, that the same type of basic lesion can lead to either translocation induction or cell inactivation, and that the basic lesion has a linear-quadratic dose relationship. The same set of parameter values is used to provide a quantitative description of the acute dose--response relationship and the effects of dose-rate and short-term, 24-h and long-term fractionation. The unusual effect of 24-h fractionation can be explained by proposing that the first dose blocks the progression of sensitive cells into the resistant compartment whilst the progression of the resistant cells into the sensitive compartment is unaffected. The analysis indicates that (1) the majority of the spermatogonial stem cells in the mouse are in the sensitive compartment; (2) that the yield of translocations is proportional to accumulated dose for chronic radiation schedules; (3) the biology of spermatogenesis should be taken into account when extrapolations are made from one animal species to another.
mesh_terms: D000818:Animals; D002875:Chromosomes / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D008297:Male; D008433:Mathematics; D051379:Mice; D008957:Models, Genetic; D013093:Spermatogonia / Q000648:ultrastructure*; D013094:Spermatozoa / Q000648:ultrastructure*; D014178:Translocation, Genetic