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 found.
Relationship Between Spermatogenic Recovery and Testicular Weight
Testicular weights of irradiated monkeys in all groups were correlated to the RI (Fig. 4). A highly significant correlation was found (P = 1.3 X 10 6). By extrapolation of the graph to a full recovery of spermatogenesis (RI = 100%), it was calculated that the weight of a fully recovered testis would be approximately 13.1 g. However, the average testicular weight of the five control monkeys, which had normal spermatogenesis, was much higher (23.3 ± 1.9 g).
Radiation Effects on Epididymis
Epididymal sections did not reveal any apparent radiation effects (Fig. 1F). A highly significant correlation was found between testis and epididymal weight (P = 1.8 X 10-15) (Fig. 5).
FIG. 3. Repopulation of the seminiferous epithelium as determined by counting the percentage of repopulated seminiferous tubular cross-sections (RI) in testes of adult rhesus monkeys of varying ages after a prepubertal dose of 5 Gy of x-irradiation. No significant progression of the repopulation after more than 3 yr postirradiation was observed (n = 26 testes [13 animals], P > 0.05).
FIG. 4. The relationship between adult testicular weight and extent of the repopulation of the seminiferous epithelium in adult rhesus monkeys after prepubertal irradiation (diamonds; n = 29 [average testicular weights and average RI values of 29 monkeys], P = 1.3 X 10~7. The square indicates the average testicular weight of unirradiated adult rhesus monkeys (n = 5).