Long-Term Effects of Irradiation Before Adulthood: DISCUSSION(5)

The results of the analysis of spermatocytes for translocation induction in spermatogonial stem cells further confirm previous, preliminary data suggesting an insensitivity of the rhesus monkey to this type of genetic change. The earlier data obtained on prepubertally irradiated monkeys were rather limited (i.e., seven individuals in total), but the present, more extensive results point…

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Long-Term Effects of Irradiation Before Adulthood: DISCUSSION(4)

Intriguingly, effects of irradiation on the morphology of Sertoli cells were found in eight monkeys. Possibly, irradiation at the time these cells were not yet terminally differentiated and still proliferating, and/or the abnormal hormone levels induced by the disappearance of most of the germ cells, altered some of the Sertoli cells. The appearance of these…

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Long-Term Effects of Irradiation Before Adulthood: DISCUSSION(3)

The discrepancy between these two weights can be explained by radiation-induced cell death of Sertoli cells in the young monkeys. In the adult testis, the Sertoli cells are terminally differentiated, nondividing cells, but at the time of irradiation, these cells were still proliferating and, hence, radiosensitive. In recent years, it has become clear that the…

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Long-Term Effects of Irradiation Before Adulthood: DISCUSSION(2)

In most of the irradiated monkeys at the time they were killed, full spermatogenesis was present in at least some tubules, indicating that these animals were potentially fertile. However, with the lowest dose given (4 Gy), in none of the monkeys was the repopulation complete. Apparently, with doses of 4 Gy and higher, all stem…

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Long-Term Effects of Irradiation Before Adulthood: DISCUSSION(1)

The termination of the TBI experiments 3-8 yr after irradiation rendered unique material to study the long-term effects of such treatment on various organs, including the testis. Despite the material gathered from different experiments being directed to study quite different consequences of irradiation, important and long-lasting effects of TBI before adulthood within the monkey testis…

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Long-Term Effects of Irradiation Before Adulthood: RESULTS(4)

Hormone Levels The levels of FSH, testosterone, estradiol, and inhibin B were measured in each monkey. Comparing the irradiated monkeys to the control monkeys, the average levels of FSH were significantly higher (6.1 ± 1.2 vs. 2.1 ± 0.1 ng/ml; P = 0.002) and of inhibin B significantly lower (691 ± 72 vs. 1227 ±…

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Long-Term Effects of Irradiation Before Adulthood: RESULTS(3)

Effect of the Interval after Irradiation on Spermatogenic Recovery In the interval group, which received a dose of 5 Gy, whether the percentage of tubular cross-sections showing repopulation kept increasing between 38 and 79 mo after irradiation was tested. However, when the interval after irradiation was correlated to the RI (Fig. 3), no significant correlation was…

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