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F. NAGY

Summary.

Using [3H]leucine and autoradiography, protein synthesis was studied in the post-natal and mature Sertoli cell nuclei of rat testes. It was shown that all nuclei were labelled in all age groups and that the amount of amino acid incorporation was greatest in newborn animals and thereafter declined until about 21 days after birth when adult levels of incorporation were realized. The realization of the adult level of protein synthetic activity coincides with the cessation of mitotic activity in Sertoli cells as well as the quickening of spermatogenic activity in the germinal cells.

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F. NAGY

Summary.

Using [3H]thymidine and autoradiography, the kinetics of cell division were studied in the immature Sertoli cells of the newborn rat testis. The average durations of the cell cycle and its components were: generation time, 16·4 hr; DNA synthesis, 10·1 hr; mitosis, 0·75 hr; G2 plus prophase, 3·6 hr.

It was also shown that the mitotic activity of the immature Sertoli cells continues until 2 weeks after birth, whereas a decreasing percentage of these cells continues to incorporate [3H]thymidine until the 7th postnatal week. Mitotic and labelling patterns determined at various stages in the maturation of the Sertoli cells were correlated with events in the seminiferous epithelium.

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F. NAGY and R. H. EDMONDS

In the present report, we present certain facets of the fine structure of the epididymal spermatozoa of an edentate, the nine-banded armadillo, Dasypus novemcinctus mexicanus. Although numerous investigators have devoted considerable attention to the morphology of spermatozoa using both transmission (Cleland & Rothschild, 1959; Bedford, 1965; Blom & Birch-Andersen, 1965; Nicander & Bane, 1966; Fawcett & Ito, 1965; Phillips, 1970; Pedersen, 1970; Phillips, 1972) and scanning (Koehler, 1970) electron microscopes, the armadillo represents a mammalian species in which the fine structure of the spermatozoa has not been investigated. While numerous features common to most mammalian spermatozoa have been observed in the armadillo, we report here some of the more distinctive features.

Sexually mature, male, nine-banded armadillos were examined during April and May. The animals were maintained for brief periods in the laboratory

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R. H. EDMONDS and F. NAGY

Electron microscope studies of the vasa deferentia and epididymides of various animals have emphasized the endoplasmic reticulum of the epithelial cell to a greater or lesser degree (Nicander & Schantz, 1961; Horstmann, 1962; Leeson & Leeson, 1964; Schmidt, 1964; Holstein, 1964). Recent studies (Hamilton, Jones & Fawcett, 1969; Hamilton, 1971a, b) have stressed the morphological arrangement and the functional rôle played by the smooth endoplasmic reticulum. These studies have pointed out an abundant and characteristic accumulation of smooth reticulum in the mouse and rat. We would like to report an apparently unique accumulation of rough endoplasmic reticulum in the initial segment of the epididymis of an edentate, the nine-banded armadillo, Dasypus novemcinctus mexicanus.

Adult, sexually mature armadillos were anaesthetized with an intraperitoneal dose of Nembutal. The intra-abdominal testis, epididymis and

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Jane N. Scott, H. Ira Fritz and F. Nagy

Summary. Adult male opossums, Didelphis virginiana, were rendered hemicryptorchid for 35 days. The cryptorchid testis exhibited a significant reduction in weight, while the contralateral testis had a compensatory weight gain compared with testes of untreated animals. Histological changes in the cryptorchid testis included fibrosis of the tunica propria, involution of the seminiferous tubules and an apparent increase in the interstitial tissue. Many seminiferous tubules were empty and germinal cells were absent. Some Sertoli cells persisted, but the cytoplasm was vacuolated. Cryptorchid testes were characterized by mononuclear leucocytic invasion around the tubules, and some eosinophils were observed. Cryptorchidism in the opossum may induce a reaction similar to experimental orchitis.