Frequency distribution of cell numbers in the spermatocysts during the annual testicular cycle in the Indian Frog Rana tigerina

Abstract

Annual changes in (1) the frequency distributions of cell numbers in the sectioned cysts of the three consecutive stages of spermatogenesis, the secondary spermatogonia, primary and secondary spermatocytes, (2) the mean numbers of spermatocysts of different stages of spermatogenesis per tubule cross section, and (3) the Leydig cell nuclear diameters were studied in the frog Rana tigerina. The mitotic proliferation of secondary spermatogonia was very slow during July-February and mitotic rate increased between March-June. The meiotic divisions, the formation of secondary spermatocytes and spermatids as well as spermiogenesis were mainly confined to May-June. The total number of spermatocysts per tubule cross section were highest during May-June. Leydig cells showed clear cut seasonal variation in their cytomorphology, being active between May-June and regressed during other months. Thus, there is a good correlation between the Leydig cell activity and proliferation and differentiation of germ cells in the testis of R. tigerina unlike that found in temperate frogs.