Differential sensitivities of spermatogonial and postspermatogonial cell stages of the mouse to induction of unscheduled DNA synthesis by ethyl- and methyl-nitrosourea.

An autoradiographic procedure was used to measure unscheduled DNA synthesis (UDS, DNA repair synthesis) in spermatogonial and postspermatogonial cell stages of mice after treatment with two doses of N-ethyl-N-nitrosourea (ENU) and N-methyl-N-nitrosourea (MNU). Significant levels of UDS were measured in type A spermatogonia, meiotic spermatocytes, round spermatids, and early elongating spermatids but not in mature spermatids. The extent of UDS varied according to the germ cell stage and the dose. At equimolar concentrations, MNU was more efficient than ENU in eliciting a UDS response in all germ cells. After ENU treatment, type A spermatogonia showed the highest UDS response, while round and elongating spermatids showed the lowest. After MNU treatment, pachytene spermatocytes exhibited the highest UDS response while type A spermatogonia showed the lowest. The high UDS response of type A spermatogonia to ENU parallels the well-known high mutational sensitivity of spermatogonia to this chemical. Similarly, the high UDS response observed in meiotic spermatocytes and early spermatid stages after MNU treatment correlates with the high mutational sensitivity of postspermatogonial stages to MNU. Thus, the present results, like the specific locus mutation studies, indicate that ENU and MNU each has a unique effect on the spermatogenic cells. This effect is likely due to the different mechanism of action of ENU and MNU at the level of DNA and also to the physiological differences between different germ-cell stages. Teratogenesis Carcinog. Mutagen. 19:339-351, 1999. Published 1999 Wiley-Liss, Inc.

[1]  R. Sotomayor,et al.  A procedure to study unscheduled DNA synthesis in rat spermatogenic cells in vivo: strain differences between Fisher-344 and Sprague-Dawley rats. , 1996, Toxicology letters.

[2]  A R Bellvé,et al.  Purification, culture, and fractionation of spermatogenic cells. , 1993, Methods in enzymology.

[3]  A. Neuhäuser-Klaus,et al.  Induction of specific-locus and dominant lethal mutations in male mice by 1-methyl-1-nitrosourea (MNU). , 1991, Mutation research.

[4]  D. Beranek.  Distribution of methyl and ethyl adducts following alkylation with monofunctional alkylating agents. , 1990, Mutation research.

[5]  P. Working,et al.  Activity of germ-cell mutagens and nonmutagens in the rat spermatocyte UDS assay. , 1988, Mutation research.

[6]  M. Meistrich,et al.  Isolation and biochemical studies of enriched populations of spermatogonia and early primary spermatocytes from rat testes. , 1986, Biology of reproduction.

[7]  P. Working,et al.  An assay to detect chemically induced DNA repair in rat spermatocytes. , 1984, Environmental mutagenesis.

[8]  E. Oakberg,et al.  The effect of ethyl-, methyl- and hydroxyethyl-nitrosourea on the mouse testis. , 1983, Mutation research.

[9]  J. Favor,et al.  Dominant cataract mutations and specific-locus mutations in mice induced by radiation or ethylnitrosourea. , 1982, Mutation research.

[10]  R. Sotomayor,et al.  Unscheduled DNA Synthesis in Mammalian Germ Cells—Its Potential Use in Mutagenicity Testing , 1982 .

[11]  G. Sega,et al.  A comparison of the molecular action of an SN1-type methylating agent, methyl nitrosourea and an SN2-type methylating agent, methyl methanesulfonate, in the germ cells of male mice. , 1981, Chemico-biological interactions.

[12]  G. Sega.  Relationship between unscheduled DNA synthesis and mutation induction in male mice. , 1980, Basic life sciences.

[13]  P. Hunsicker,et al.  Specific-locus test shows ethylnitrosourea to be the most potent mutagen in the mouse. , 1979, Proceedings of the National Academy of Sciences of the United States of America.

[14]  R. Sotomayor,et al.  An autoradiographic study of unscheduled DNA synthesis in the germ cells of male mice treated with X-rays and methyl methanesulfonate. , 1979, Mutation research.

[15]  C. Huckins,et al.  Morphological and quantitative analysis of spermatogonia in mouse testes using whole mounted seminiferous tubules. I. The normal testes , 1978, The Anatomical record.

[16]  P. D. Lawley,et al.  Alkylation of deoxyribonucleic acid by carcinogens dimethyl sulphate, ethyl methanesulphonate, N-ethyl-N-nitrosourea and N-methyl-N-nitrosourea. Relative reactivity of the phosphodiester site thymidylyl(3'-5')thymidine. , 1978, The Biochemical journal.

[17]  K. V. Shooter,et al.  The stability of methyl and ethyl phosphotriesters in DNA in vivo. , 1977, Chemico-biological interactions.

[18]  G. M. Connell,et al.  CHAPTER 10 – The Interstitial Tissue of the Testis , 1977 .

[19]  A. Steinberger,et al.  CHAPTER 11 – The Sertoli Cells , 1977 .

[20]  B. Singer,et al.  All oxygens in nucleic acids react with carcinogenic ethylating agents , 1976, Nature.

[21]  L. Sun,et al.  The specificity of different classes of ethylating agents toward various sites of HeLa cell DNA in vitro and in vivo. , 1975, Biochemistry.

[22]  R. Sotomayor,et al.  Induction of translocations by cyclophosphamide in different germ cell stages of male mice: cytological characterization and transmission. , 1975, Mutation research.

[23]  W. R. Bruce,et al.  Cellular composition of fractions of mouse testis cells following velocity sedimentation separation. , 1973, Experimental eye research.

[24]  Z. Darżynkiewicz,et al.  Unscheduled synthesis of DNA during mammalian spermatogenesis in response to UV irradiation. , 1973, The Journal of experimental zoology.

[25]  A. Léonard.  Observations on Meiotic Chromosomes of the Male Mouse as a Test of the Potential Mutagenicity of Chemicals in Mammals , 1973 .

[26]  W. Verly,et al.  Alkylation of phosphates and stability of phosphate triesters in DNA. , 1972, European journal of biochemistry.

[27]  A. Chandley,et al.  Radiation-initiated DNA synthesis in spermatogenic cells of the mouse. , 1971, Experimental cell research.

[28]  E. Oakberg.  Spermatogonial stem‐cell renewal in the mouse , 1971, The Anatomical record.

[29]  J. Roberts,et al.  Quantitative aspects of the repair of alkylated DNA in cultured mammalian cells. II. Non-semiconservative DNA synthesis ('repair synthesis') in HeLa and Chinese hamster cells following treatment with alkylating agents. , 1971, Chemico-biological interactions.

[30]  H. Seidler.  D. Gude: Autographic Techniques. – Localization of Radioisotopes in Biological Material. Prentice Hall Biological Techniques Series, 113 Seiten, Prentice Hall, Englewood Cliffs, N. J., 1968. Preis: 60 s , 1971 .

[31]  C. E. Ford,et al.  AN AIR-DRYING METHOD FOR MEIOTIC PREPARATIONS FROM MAMMALIAN TESTES. , 1964, Cytogenetics.

[32]  C. P. Leblond,et al.  Renewal of spermatogonia in the rat. , 1953, The American journal of anatomy.