sdf-1 up-regulation in kidney and skin in response to preconditioning radiation. (A) Quantitative RT-PCR of whole zebrafish kidneys 1 day after fish received Cs¹³⁷ radiation. n = 5 adult fish per group. (B) Quantitative RT-PCR of isolated renal tubule fractions and nontubule fractions 1 day after fish received Cs¹³⁷ radiation. Data represent pooled results from 2 independent biologic experiments, with an ultimate total of 20 to 24 fish per condition. (C) Quantitative RT-PCR of skin 1 day (above) and 2 days (below) after fish received x-ray irradiation; n = skin from 5 fish per condition. (A-C) Experimental primers were normalized to B-actin controls. Error bars show mean RQ and SEM between duplicate quantitative RT-PCR reactions. Each radiation group is compared with the 0-Gy reference. ***P < .001 (analysis of variance with Tukey postanalysis). **.001 < P < .01 (analysis of variance with Tukey postanalysis). *.01 < P < .05 (analysis of variance with Tukey postanalysis).