In males collected after late-May, spermatozoa were already evacuated, and the presence of spermatogonia or spermatocytes in the posterior parts of the testes indicated the initiation of the next spermatogenetic
Seasonal changes in the functional activity of the interstitial and spermatogenetic
tissues of the green frog, Rana esculenta.
In order to understand variation in reproductive activity of tropical lizards, Sherbrooke (1975) grouped the reproductive strategies into three possible types: (1) continuous, without variation in reproductive activity, (2) continuous, with variation in reproductive activity, noted by seasonal variation either in testis size and/or spermatogenetic
activity or the percentage of fertile or ovigerous females, and (3) non-continuous, with periods when all individuals are reproductively inactive, males lack mature spermatozoa in their testes and epididymis and females lack large yoked ova and/or oviductal eggs.
In contrast, the spermatocyte-II stage is thought to be the shortest spermatogenetic
step, because, as occurs in teleosts in general, it is the least frequent in histological samples.
24) If prolonged exposure to high temperature were the only cause of spermatogenetic
lesion in human cryptorchidism, as occurs in experimental cryptorchidism, the lesions should be diffuse and should be equally severe in all of the seminiferous tubules.
Microdeletions in these three regions are associated with various spermatogenetic
alterations including Sertoli cell-only syndrome (SCOS), maturation arrest, and hypospermatogenesis.
Seminiferous tubules were labeled as type A, B, C according to the spermatogenetic
activity variations between tubules; A: Tubule consisting of sertoli cells and spermatogonia, no spermatocytes or spermatids; B: Tubule consisting of sertoli cells, spermatogonia and spermatocytes, no spermatids; C: Tubule consisting of sertoli cells, spermatogonia, spermatocytes and spermatids.