Fig. 7. Cytometric analysis of proliferation determined by BrdU incorporation. (A) Pulse BrdU followed by cytometry of whole embryo suspensions after 1 hour. Typical profiles for wild-type (left panel) and Igf2^+m/-p (right panel) litter-matched embryos aged at E9.75 by cell number. Numbers indicate mean cell number above the horizontal line as a percentage of whole embryos (n=16). (B) Pulse-chase BrdU followed by cytometry of whole embryo suspensions after 24 hours in vivo. Typical profiles for wild-type (left panel) and Igf2^+m/-p (right panel) of litter-matched embryos injected at E8.5 and dissected at E9.5 (plugging). The cells above the horizontal line were labelled as after a single BrdU pulse. Numbers indicate mean cell number above the horizontal line as a percentage of whole embryos (n=12). (C) Mean±s.e.m. of percentage of pulse BrdU incorporation as in A at E8.5 (n=8), E9.75 (n=16) and E10.5 (n=13). The only significant differences occurred at E9.75 (P=0.006). (D) Means±s.e.m. of percentage of pulse (E8.5) chase (to E9.5) BrdU incorporation as in B. Fewer cells divided in Igf2^+m/-p, as significantly more retained label as if pulsed at 1 hour (n=12, litter-matched samples).