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The effect of 90Sr given to pregnant mice on spermatogenesis in the male offspring: a comparison with the effect on the ovaries in the female offspring.

In previous studies in which the effect of intra-uterine exposure to 90Sr on the mouse was ascertained, the foetal ovary was found to be very sensitive. This paper reports the effects of the administration of 90Sr on spermatogenesis in the male littermates of these female mice. Doses of 370 and 740 kBq 90Sr administered to the dam at day 19 of gestation were found to cause a transient retardation in the appearance of more advanced types of germ cells in the testis. In comparison with the control testes, in the 90Sr treated mice less tubular cross-sections showed spermatocytes or round spermatids at days 14 and 2i p.p., respectively. After 56 days, spermatogenesis in the 90Sr treated mice was similar to that in control mice. Doses of 92.5 and 185 kBq 90Sr had no visible effect. It is concluded that the foetal testis is much less vulnerable to the damaging effects of 90Sr administration than the ovary, in which a dose of 92.5 kBq permanently decreased germ cell numbers to 40 per cent of the control numbers. Nevertheless, presumably also in the foetal testis, many germ cell will be killed by the radiation from the 90Sr. However, in the testis the surviving stem cells apparently quickly restore their numbers at the cost of a delay in the production of differentiating cells.