109Cd Distribution in the Testis and Control Tissues (Fig. 3; Table 1)
By 24 h postinjection, < 1% of the injected dose had accumulated in testis, an amount lower than testicular mass as a percentage of body weight (< 2%); however, the same fraction of administered 109Cd was retained in the testis for at least 7 days postinjection (Table 1). Significantly, intra-testicular 109Cd concentrations were stage dependent, with highest levels in regions with stem cells (GZ) and sper-matogonial-stage cysts (PrM) and progressively lower levels in regions with more mature developmental stages. buy cheap antibiotics
This resulted in a decreasing intratesticular 109Cd gradient (immature > mature). Absolute levels of radiolabeled Cd increased in all testicular regions between 1 and 3 days and between 1 and 7 days postinjection, but the increase was greatest in GZ and PrM regions. Thus, when measured as the fold difference between least mature (GZ) and most mature (PoM) regions at 1, 3, and 7 days postinjection, the 109Cd gradient was 3-, 4.7-, and 3.9-fold at the respective time points. Regardless of position in the gradient, testicular 109Cd levels 3 and 7 days after tracer injection always exceeded those in plasma.
FIG. 3. Stage-related distribution of 109Cd in A) male reproductive organs and B) control tissues. Note scale difference between A and B. 109Cd levels were determined 1, 3, or 7 days after tracer injection. VAS, vas deferens; KID, kidney; LIV liver; HRT, heart; MUS, muscle. Values represent the mean and SEM of 3 animals, each determined in triplicate. Intratesticu-lar values were analyzed by two-way AN-OVA as a function of region (p < 0.001) and time (p < 0.001), and significant differences were determined by the Student-Newman-Keuls post hoc comparison test (p< 0.05). For a given day posttracer, regions with different letters differ significantly: Day 1, a-c; Day 3, k-m; Day 7, x-z. For a given region, significant differences between days are indicated by an asterisk. Values for EO, VAS, and nonre-productive control tissues were analyzed separately as a function of time after tracer (one-way ANOVA).