spematogenesis in some of Australian marsupials

Abstract

Eight stages of spermatogenesis, based on cellular association, have been found in four species of Australian marsupials: Macvopus eugenii, M. rufogriseus, Trichosurus vulpecula, and Perameles nasuta. The cellular association are similar to those in eutherian mammals, and the frequency with which these stages occur in these marsupials are also similar. Following [3H]thymidine injections directly into the testis or into a testicular artery, the length of one cycle of the spermatogenic epithelium was estimated by autoradiography to be 17, 16, and 15 days for M. rufogriseus, M. eugenii, and T, vulpecula respectively; labelled spermatozoa first appeared in the urine 61 and 56 days after injection in M. eugenii and T. vulpecula respectively. From these data the minimum transit time through the epididymis can be calculated to be 13 and 11 days respectively. From the number of cells labelled in tubular cross-sections at different stages of spermatogenesis 1 hr after an intra-arterial injection of [3H]thymidine, it was concluded that at least four synchronized peaks of mitosis occurred in the spermatogonia of M. rufogriseus.