Fig. 8. Mean number of BrdU-ir cells (per 100 µm lamella length) plotted against sampling date. Data are given as means ± S.E.M. Basal cell counts are indicated by red triangles; mid-apical cell counts are indicated by blue triangles. Data are superimposed on a plot of mean plasma T₄ levels for each sampling date (black squares). Sample sizes for BrdU-ir cell data for each date are shown in parentheses.