STAGES OF THE CYCLE OF THE SEMINIFEROUS EPITHELIUM OF THE VISCACHA (LAGOSTOMUS-MAXIMUS MAXIMUS)

The adult male viscacha (Lagostomus maximus maximus) is a seasonal rod ent. It exhibits a short period of testicular regression with partial arrest of spermatogenesis during winter (July-August). The present stu dy provides the first description of the viscacha spermatogenic cycle during the period of maximum gonadal activity (summer-autumn). The tes tes were processed by using conventional techniques of light and elect ron microscopy. One-micrometer-thick sections stained with toluidine b lue were used to clearly define the different cell associations. Sperm atogenesis in this rodent is well organized and synchronized and has b een divided into nine stages. The present classification is based on t he morphogenesis of the acrosomal system (stages I-V) and the degree o f elongation and condensation of the heads of the differentiating sper matids (stages VI-IX). Stage I is principally defined by round spermat ids with a well-developed, juxtanuclear Golgi complex and without acro somal components that are visible under the light microscope. Sperm re lease from the viscacha seminiferous epithelium occurs either in late stage III or in early stage IV. Stage IX is characterized by diplotene spermatocytes, figures of meiosis I or II, and secondary spermatocyte s. (C) 1998 Wiley-Liss, Inc.