Northern Blots. Northern blot of the total RNA extracted from the liver of both rat strains. The hybridisation was done with a radioactive probe specific for the luciferase mRNA and then with a probe specific for the β-Actine mRNA. Lane 1–8: Wag/Rij rats, lane 1–2 animals injected with Ad5 Adapt Empty, lane 3–8: animals injected with Ad5 Adapt Luc. Lane 9–16: Brown Norway rats, lane 9–10 animals injected with Ad5 Adapt Empty, lane 11–16: animals injected with Ad5 Adapt Luc. The quantification of the signals with the phosphorimager shows that there is no difference in the quantity of β-actine transcript whereas there is about 10 times more luciferase transcripts in the liver of the Brown Norway rats than in the Wag/Rij rats. Means values +/- sd expressed in arbitrary units are depicted on the gel.