P32Autoradiographs of Mouse Testis: Preliminary Observations of the Timing of Spermatogenic Stages

Abstract

(1) Testis material from mice killed 2, 5, 9 and 12 days after injection of 200 μC of P³² was autoradiographed by the stripping film technique and examined cytologically. (2) Cells at different stages of spermatogenesis were found to take up P³² differently. Some preliminary estimates as to the time taken by various stages of spermatogenesis are (a) from spermatogonial metaphase to early meiotic prophase, between 3 and 9 days; (b) from diakinesis to second metaphase, 4 days or less; (c) from diakinesis to immature sperm, 7 days or more; (d) from spermatogonial metaphase to immature sperm, more than 10 days. (3) Leydig cells were observed to show a strong uptake of P³² within the first 2 days. Some possible explanations for this observation are put forward.