Fig. 2. Plots of plasma [³H]3OMD-glucose and [¹⁴C]L-glucose concentration (mean ± S.E.M.) as a function of time since feeding the probes (gavage). The units for concentration are proportion per gram plasma, because values of d.p.m. g^-1 plasma were normalized to d.p.m. dose for each individual. (A) Measurements made under relatively nonsaturating conditions (200 mmol l^-1 mannitol in the gavage solution, N=7 birds); (B) measurements made under more saturating conditions (i.e. 200 mmol l^-1 3OMD-glucose replaced mannitol in the gavage solution, N=6). Filled symbols and solid lines, [¹⁴C]L-glucose; unfilled symbols and broken lines, [³H]3OMD-glucose.