| First Author | Russell LB | Year | 1992 |
| Journal | Mutat Res | Volume | 282 |
| Issue | 3 | Pages | 151-8 |
| PubMed ID | 1378547 | Mgi Jnum | J:73421 |
| Mgi Id | MGI:2155241 | Doi | 10.1016/0165-7992(92)90089-z |
| Citation | Russell LB, et al. (1992) Melphalan, a second chemical for which specific-locus mutation induction in the mouse is maximum in early spermatids. Mutat Res 282(3):151-8 |
| abstractText | Melphalan (MLP), a bifunctional alkylating agent structurally related to the highly mutagenic chemical chlorambucil (CHL), was found to induce high frequencies of specific-locus mutations in postspermatogonial germ cells of the mouse, and to be one of only a few chemicals that is also mutagenic in spermatogonial stem cells. Productivity patterns following MLP exposures resembled those that had been found for CHL. Mutation rates in successive male germ-cell stages were measured at three MLP-exposure levels in a total of 95,375 offspring. While the induced (experimental minus historical-control) mutation rate is relatively low in stem-cell spermatogonia (1.2 x 10(-5) per locus at a weighted-mean exposure of 7.3 mg/kg), it is about 5 times higher in poststem-cell stages overall, and peaks at 26.7 x 10(-5) per locus in early spermatids at a weighted-mean exposure of only 5.7 mg/kg. This 'type-2 pattern' of mutation yield (Russell et al., 1990), i.e., peak sensitivity in early spermatids, has heretofore been found for only one other chemical, CHL. Mutation-rate data earlier reported for CHL (Russell et al., 1989) were augmented in the present study for comparison with MLP-induced rates. Because of the greater toxicity of MLP, average exposures used for this chemical were only about one-half of those for CHL. When MLP and CHL mutation rates are extrapolated to equimolar doses, they appear very similar for poststem-cell stages overall. However, in the case of CHL, a somewhat higher proportion of the mutations is induced in early spermatids than in the case of MLP. |
